What is a Monoamine Oxidase Inhibitor?

Introduction

Monoamine oxidase inhibitors (MAOIs) are a class of drugs that inhibit the activity of one or both monoamine oxidase enzymes: monoamine oxidase A (MAO-A) and monoamine oxidase B (MAO-B).

They are best known as highly efficacious antidepressants, as well as effective therapeutic agents for panic disorder and social phobia. They are particularly effective in treatment-resistant depression and atypical depression. They are also used in the treatment of Parkinson’s disease and several other disorders.

Reversible inhibitors of monoamine oxidase A (RIMAs) are a subclass of MAOIs that selectively and reversibly inhibit the MAO-A enzyme. RIMAs are used clinically in the treatment of depression and dysthymia. Due to their reversibility, they are safer in single-drug overdose than the older, irreversible MAOIs, and weaker in increasing the monoamines important in depressive disorder. RIMAs have not gained widespread market share in the United States.

New research into MAOIs indicates that much of the concern over their supposed dangerous dietary side effects stems from misconceptions and misinformation, and that they are still underutilised despite demonstrated efficacy. New research also questions the validity of the perceived severity of dietary reactions, which has been based on outdated research. Despite this, many psychiatrists, who have little or no knowledge of and experience with monoamine oxidase inhibitors (and are thus unaware of their significant benefits), still reserve them as a last line of treatment, used only when other classes of antidepressant drugs (for example, selective serotonin reuptake inhibitors (SSRIs) and tricyclic antidepressants) have failed.

Brief History

MAOIs started off due to the serendipitous discovery that iproniazid was a potent MAO inhibitor (MAOI). Originally intended for the treatment of tuberculosis, in 1952, iproniazid’s antidepressant properties were discovered when researchers noted that the depressed patients given iproniazid experienced a relief of their depression. Subsequent in vitro work led to the discovery that it inhibited MAO and eventually to the monoamine theory of depression. MAOIs became widely used as antidepressants in the early 1950s. The discovery of the 2 isoenzymes of MAO has led to the development of selective MAOIs that may have a more favourable side-effect profile.

The older MAOIs’ heyday was mostly between the years 1957 and 1970. The initial popularity of the ‘classic’ non-selective irreversible MAO inhibitors began to wane due to their serious interactions with sympathomimetic drugs and tyramine-containing foods that could lead to dangerous hypertensive emergencies. As a result, the use by medical practitioners of these older MAOIs declined. When scientists discovered that there are two different MAO enzymes (MAO-A and MAO-B), they developed selective compounds for MAO-B, (for example, selegiline, which is used for Parkinson’s disease), to reduce the side-effects and serious interactions. Further improvement occurred with the development of compounds (moclobemide and toloxatone) that not only are selective but cause reversible MAO-A inhibition and a reduction in dietary and drug interactions. Moclobemide, was the first reversible inhibitor of MAO-A to enter widespread clinical practice.

A transdermal patch form of the MAOI selegiline, called Emsam, was approved for use in depression by the US Food and Drug Administration (FDA) on 28 February 2006.

Medical Uses

MAOIs have been found to be effective in the treatment of panic disorder with agoraphobia, social phobia, atypical depression or mixed anxiety disorder and depression, bulimia, and post-traumatic stress disorder, as well as borderline personality disorder, and obsessive compulsive disorder (OCD). MAOIs appear to be particularly effective in the management of bipolar depression according to a retrospective-analysis from 2009. There are reports of MAOI efficacy in OCD, trichotillomania, body dysmorphic disorder, and avoidant personality disorder, but these reports are from uncontrolled case reports.

MAOIs can also be used in the treatment of Parkinson’s disease by targeting MAO-B in particular (therefore affecting dopaminergic neurons), as well as providing an alternative for migraine prophylaxis. Inhibition of both MAO-A and MAO-B is used in the treatment of clinical depression and anxiety.

MAOIs appear to be particularly indicated for outpatients with dysthymia complicated by panic disorder or hysteroid dysphoria.

Newer MAOIs such as selegiline (typically used in the treatment of Parkinson’s disease) and the reversible MAOI moclobemide provide a safer alternative and are now sometimes used as first-line therapy.

Side Effects

Hypertensive Crisis

People taking MAOIs generally need to change their diets to limit or avoid foods and beverages containing tyramine, which is found in products such as cheese, soy sauce, and salami. If large amounts of tyramine are consumed, they may suffer a hypertensive crisis, which can be fatal. Examples of foods and beverages with potentially high levels of tyramine include animal liver and fermented substances, such as alcoholic beverages and aged cheeses. Excessive concentrations of tyramine in blood plasma can lead to hypertensive crisis by increasing the release of norepinephrine (NE), which causes blood vessels to constrict by activating alpha-1 adrenergic receptors. Ordinarily, MAO-A would destroy the excess NE; when MAO-A is inhibited, however, NE levels get too high, leading to dangerous increases in blood pressure.

RIMAs are displaced from MAO-A in the presence of tyramine, rather than inhibiting its breakdown in the liver as general MAOIs do. Additionally, MAO-B remains free and continues to metabolise tyramine in the stomach, although this is less significant than the liver action. Thus, RIMAs are unlikely to elicit tyramine-mediated hypertensive crisis; moreover, dietary modifications are not usually necessary when taking a reversible inhibitor of MAO-A (i.e. moclobemide) or low doses of selective MAO-B inhibitors (e.g. selegiline 6 mg/24 hours transdermal patch).

Drug Interactions

The most significant risk associated with the use of MAOIs is the potential for drug interactions with over-the-counter, prescription, or illegally obtained medications, and some dietary supplements (e.g. St. John’s wort, tryptophan). It is vital that a doctor supervise such combinations to avoid adverse reactions. For this reason, many users carry an MAOI-card, which lets emergency medical personnel know what drugs to avoid (e.g. adrenaline (epinephrine) dosage should be reduced by 75%, and duration is extended).

Tryptophan supplements should not be consumed with MAOIs as the potentially fatal serotonin syndrome may result.

MAOIs should not be combined with other psychoactive substances (antidepressants, painkillers, stimulants, including prescribed, OTC and illegally acquired drugs, etc.) except under expert care. Certain combinations can cause lethal reactions, common examples including SSRIs, tricyclics, MDMA, meperidine, tramadol, and dextromethorphan. Drugs that affect the release or reuptake of epinephrine, norepinephrine, or dopamine typically need to be administered at lower doses due to the resulting potentiated and prolonged effect. MAOIs also interact with tobacco-containing products (e.g. cigarettes) and may potentiate the effects of certain compounds in tobacco. This may be reflected in the difficulty of smoking cessation, as tobacco contains naturally occurring MAOI compounds in addition to the nicotine.

While safer than general MAOIs, RIMAs still possess significant and potentially serious drug interactions with many common drugs; in particular, they can cause serotonin syndrome or hypertensive crisis when combined with almost any antidepressant or stimulant, common migraine medications, certain herbs, or most cold medicines (including decongestants, antihistamines, and cough syrup).

Ocular alpha-2 agonists such as brimonidine and apraclonidine are glaucoma medications which reduce intraocular pressure by decreasing aqueous production. These alpha-2 agonists should not be given with oral MAOIs due to the risk of hypertensive crisis.

Withdrawal

Antidepressants including MAOIs have some dependence-producing effects, the most notable one being a discontinuation syndrome, which may be severe especially if MAOIs are discontinued abruptly or too rapidly. The dependence-producing potential of MAOIs or antidepressants in general is not as significant as benzodiazepines, however. Discontinuation symptoms can be managed by a gradual reduction in dosage over a period of weeks, months or years to minimise or prevent withdrawal symptoms.

MAOIs, as with most antidepressant medication, may not alter the course of the disorder in a significant, permanent way, so it is possible that discontinuation can return the patient to the pre-treatment state. This consideration complicates prescribing between a MAOI and a SSRI, because it is necessary to clear the system completely of one drug before starting another. One physician organisation recommends the dose to be tapered down over a minimum of four weeks, followed by a two week washout period. The result is that a depressed patient will have to bear the depression without chemical help during the drug-free interval. This may be preferable to risking the effects of an interaction between the two drugs.

Interactions

The MAOIs are infamous for their numerous drug interactions, including the following kinds of substances:

  • Substances that are metabolised by monoamine oxidase, as they can be boosted by up to several-fold.
  • Substances that increase serotonin, norepinephrine, or dopamine activity, as too much of any of these neurochemicals can result in severe acute consequences, including serotonin syndrome, hypertensive crisis, and psychosis, respectively.

Such substances that can react with MAOIs include:

  • Phenethylamines: 2C-B, mescaline, phenethylamine (PEA), etc.
    • Amphetamines: amphetamine, MDMA, dextroamphetamine, methamphetamine, DOM, etc.
  • Tryptamines: DMT (MAOIs prevent oxidisation of DMT in the digestive tract, which renders it biologically inert. This allows it to be absorbed in the stomach and small intestine, allowing one to experience the effects of DMT by taking it orally i.e. by Ayahuasca. This anti-oxidation effect can also be observed when administering DMT by inhalation, and it can serve to potentiate the length of the experience.)
  • Norepinephrine, and/or dopamine reuptake inhibitors:
    • Serotonin-norepinephrine reuptake inhibitors (SNRIs): desvenlafaxine, duloxetine, milnacipran, venlafaxine.
    • Norepinephrine-dopamine reuptake inhibitors (NDRIs): amineptine, bupropion, methylphenidate, nomifensine.
    • Norepinephrine reuptake inhibitors (NRIs): atomoxetine, mazindol, reboxetine.
    • Tricyclic antidepressants (TCAs): amitriptyline, butriptyline, clomipramine, desipramine, dosulepin, doxepin, imipramine, lofepramine, nortriptyline, protriptyline, trimipramine.
    • Tetracyclic antidepressants (TeCAs): amoxapine, maprotiline.
    • Phenylpiperidine derivative opioids: meperidine/pethidine, tramadol, methadone, fentanyl, dextropropoxyphene, propoxyphene.
    • Others: brompheniramine, chlorpheniramine, cocaine, cyclobenzaprine, dextromethorphan (DXM), ketamine, MDPV, nefazodone, phencyclidine (PCP), pheniramine, sibutramine, trazodone
  • Serotonin, norepinephrine, and/or dopamine releasers: 4-methylaminorex (4-MAR), amphetamine, benzphetamine, cathine, cathinone, diethylcathinone, ephedrine, levmetamfetamine, lisdexamfetamine, MDMA (“Ecstasy”), methamphetamine, pemoline, phendimetrazine, phenethylamine (PEA), phentermine, propylhexedrine, pseudoephedrine, phenylephrine, tyramine.
  • Local and general anaesthetic in surgery and dentistry, in particular those containing epinephrine. There is no universally taught or accepted practice regarding dentistry and use of MAOIs such as phenelzine, and therefore it is vital to inform all clinicians, especially dentists, of the potential effect of MAOIs and local anaesthesia. In preparation for dental work, withdrawal from phenelzine is specifically advised; since this takes two weeks, however, it is not always a desirable or practical option. Dentists using local anaesthesia are advised to use a non-epinephrine anaesthetic such as mepivacaine at a level of 3%. Specific attention should be paid to blood pressure during the procedure, and the level of the anaesthetic should be regularly and appropriately topped-up, for non-epinephrine anaesthetics take longer to come into effect and wear off faster. Patients taking phenelzine are advised to notify their psychiatrist prior to any dental treatment.
  • Certain other supplements may exhibit below-therapeutic-level MAOI activity: Hypericum perforatum (“St John’s wort”), inositol, Rhodiola rosea, S-adenosyl-L-methionine (SAMe).
  • Antibiotics such as linezolid.
  • Other monoamine oxidase inhibitors.

Mechanism of Action

MAOIs act by inhibiting the activity of monoamine oxidase, thus preventing the breakdown of monoamine neurotransmitters and thereby increasing their availability. There are two isoforms of monoamine oxidase, MAO-A and MAO-B. MAO-A preferentially deaminates serotonin, melatonin, epinephrine, and norepinephrine. MAO-B preferentially deaminates phenethylamine and certain other trace amines; in contrast, MAO-A preferentially deaminates other trace amines, like tyramine, whereas dopamine is equally deaminated by both types.

Reversibility

The early MAOIs covalently bound to the monoamine oxidase enzymes, thus inhibiting them irreversibly; the bound enzyme could not function and thus enzyme activity was blocked until the cell made new enzymes. The enzymes turn over approximately every two weeks. A few newer MAOIs, a notable one being moclobemide, are reversible, meaning that they are able to detach from the enzyme to facilitate usual catabolism of the substrate. The level of inhibition in this way is governed by the concentrations of the substrate and the MAOI.

Harmaline found in Peganum harmala, Banisteriopsis caapi, and Passiflora incarnata is a reversible inhibitor of monoamine oxidase A (RIMA).

Selectivity

In addition to reversibility, MAOIs differ by their selectivity of the MAO enzyme subtype. Some MAOIs inhibit both MAO-A and MAO-B equally, other MAOIs have been developed to target one over the other.

MAO-A inhibition reduces the breakdown of primarily serotonin, norepinephrine, and dopamine; selective inhibition of MAO-A allows for tyramine to be metabolised via MAO-B. Agents that act on serotonin if taken with another serotonin-enhancing agent may result in a potentially fatal interaction called serotonin syndrome or with irreversible and unselective inhibitors (such as older MAOIs), of MAO a hypertensive crisis as a result of tyramine food interactions is particularly problematic with older MAOIs. Tyramine is broken down by MAO-A and MAO-B, therefore inhibiting this action may result in its excessive build-up, so diet must be monitored for tyramine intake.

MAO-B inhibition reduces the breakdown mainly of dopamine and phenethylamine so there are no dietary restrictions associated with this. MAO-B would also metabolize tyramine, as the only differences between dopamine, phenethylamine, and tyramine are two phenylhydroxyl groups on carbons 3 and 4. The 4-OH would not be a steric hindrance to MAO-B on tyramine. Selegiline is selective for MAO-B at low doses, but non-selective at higher doses.

List of MAO Inhibiting Drugs

Marketed MAOIs

  • Nonselective MAO-A/MAO-B inhibitors.
    • Hydrazine (antidepressant).
      • Isocarboxazid (Marplan).
      • Hydracarbazine.
      • Phenelzine (Nardil).
    • Non-hydrazines.
      • Tranylcypromine (Parnate, Jatrosom).
  • Selective MAO-A inhibitors.
    • Bifemelane (Alnert, Celeport) (available in Japan).
    • Moclobemide (Aurorix, Manerix).
    • Pirlindole (Pirazidol) (available in Russia).
  • Selective MAO-B inhibitors.
    • Rasagiline (Azilect).
    • Selegiline (Deprenyl, Eldepryl, Emsam, Zelapar).
    • Safinamide (Xadago).

Linezolid is an antibiotic drug with weak, reversible MAO-inhibiting activity.

Methylene blue, the antidote indicated for drug-induced methemoglobinemia, among a plethora of other off-label uses, is a highly potent, reversible MAO inhibitor.

MAOIs that have been Withdrawn from the Market

  • Nonselective MAO-A/MAO-B inhibitors:
    • Hydrazines.
      • Benmoxin (Nerusil, Neuralex).
      • Iproclozide (Sursum).
      • Iproniazid (Marsilid, Iprozid, Ipronid, Rivivol, Propilniazida) (discontinued worldwide except for France).
      • Mebanazine (Actomol).
      • Nialamide (Niamid).
      • Octamoxin (Ximaol, Nimaol).
      • Pheniprazine (Catron).
      • Phenoxypropazine (Drazine).
      • Pivalylbenzhydrazine (Tersavid).
      • Safrazine (Safra) (discontinued worldwide except for Japan).
    • Non-hydrazines.
      • Caroxazone (Surodil, Timostenil).
  • Selective MAO-A inhibitors:
    • Minaprine (Cantor).
    • Toloxatone (Humoryl).

List of RIMAs

  • Marketed pharmaceuticals:
    • Moclobemide (Aurorix, Manerix).
  • Other pharmaceuticals.
    • Brofaromine (Consonar).
    • Caroxazone (Surodil, Timostenil).
    • Eprobemide (Befol).
    • Methylene blue.
    • Metralindole (Inkazan).
    • Minaprine (Cantor).
    • Pirlindole (Pirazidol).
  • Naturally occurring RIMAs in plants:
    • Curcumin (selectivity for MAO-A and reliability of research on curcumin are disputed).
    • Harmaline.
    • Harmine.
  • Research compounds:
    • Amiflamine (FLA-336).
    • Befloxatone (MD-370,503).
    • Cimoxatone (MD-780,515).
    • Esuprone.
    • Sercloremine (CGP-4718-A).
    • Tetrindole.
    • CX157 (TriRima).

What is the Management of Depression?

Introduction

Depression is a symptom of some physical diseases; a side effect of some drugs and medical treatments; and a symptom of some mood disorders such as major depressive disorder or dysthymia. Physical causes are ruled out with a clinical assessment of depression that measures vitamins, minerals, electrolytes, and hormones. Management of depression may involve a number of different therapies: medications, behaviour therapy, psychotherapy, and medical devices.

Though psychiatric medication is the most frequently prescribed therapy for major depression, psychotherapy may be effective, either alone or in combination with medication. Combining psychotherapy and antidepressants may provide a “slight advantage”, but antidepressants alone or psychotherapy alone are not significantly different from other treatments, or “active intervention controls”. Given an accurate diagnosis of major depressive disorder, in general the type of treatment (psychotherapy and/or antidepressants, alternate or other treatments, or active intervention) is “less important than getting depressed patients involved in an active therapeutic program.”

Psychotherapy is the treatment of choice in those under the age of 18, with medication offered only in conjunction with the former and generally not as a first line agent. The possibility of depression, substance misuse or other mental health problems in the parents should be considered and, if present and if it may help the child, the parent should be treated in parallel with the child.

Psychotherapy and Behaviour Therapy

There are a number of different psychotherapies for depression which are provided to individuals or groups by psychotherapists, psychiatrists, psychologists, clinical social workers, counsellors or psychiatric nurses. With more chronic forms of depression, the most effective treatment is often considered to be a combination of medication and psychotherapy. Psychotherapy is the treatment of choice in people under 18. A meta-analysis examined the effectiveness of psychotherapy for depression across ages from younger than 13 years to older than 75 years. It summarizes results from 366 trials included 36,702 patients. It found that the best results were for young adults, with an average effect size of g=.98 (95% CI, 0.79-1.16). The effects were smallest for young children (<13 years), g = .35 (95% CI, 0.15-0.55), and second largest in the oldest group, g = .97 (95% CI, 0.42-1.52). The study was not able to compare the different types of therapy to each other. Most of the studies with children used therapies originally developed with adults, which may have reduced the effectiveness. The greater benefits with young adults might be due to a large number of studies including college students, who might have an easier time learning therapy skills and techniques. Most of the studies in children were done in the USA, whereas in older age groups, more balanced numbers of studies came from Europe and other parts of the world as well.

As the most studied form of psychotherapy for depression, cognitive behavioural therapy (CBT) is thought to work by teaching clients to learn a set of cognitive and behavioural skills, which they can employ on their own. Earlier research suggested that cognitive behavioural therapy was not as effective as antidepressant medication in the treatment of depression; however, more recent research suggests that it can perform as well as antidepressants in treating patients with moderate to severe depression. Beck’s treatment manual, Cognitive therapy of depression, has undergone the most research and accumulated the most evidence for its use. However, a number of other CBT manuals also have evidence to support their effectiveness with depression.

The effect of psychotherapy on patient and clinician rated improvement as well as on revision rates have declined steadily from the 1970s.

A systematic review of data comparing low-intensity CBT (such as guided self-help by means of written materials and limited professional support, and website-based interventions) with usual care found that patients who initially had more severe depression benefited from low-intensity interventions at least as much as less-depressed patients.

For the treatment of adolescent depression, one published study found that CBT without medication performed no better than a placebo, and significantly worse than the antidepressant fluoxetine. However, the same article reported that CBT and fluoxetine outperformed treatment with only fluoxetine. Combining fluoxetine with CBT appeared to bring no additional benefit in two different studies or, at the most, only marginal benefit, in a fourth study.

Behaviour therapy for depression is sometimes referred to as behavioural activation. Studies exist showing behavioural activation to be superior to CBT. In addition, behavioural activation appears to take less time and lead to longer lasting change. Two well-researched treatment manuals include Social skills training for depression and Behavioural activation treatment for depression.

Emotionally focused therapy, founded by Sue Johnson and Les Greenberg in 1985, treats depression by identifying and processing underlying emotions. The treatment manual, Facilitating emotional change, outlines treatment techniques.

Acceptance and commitment therapy (ACT), a mindfulness form of CBT, which has its roots in behaviour analysis, also demonstrates that it is effective in treating depression, and can be more helpful than traditional CBT, especially where depression is accompanied by anxiety and where it is resistant to traditional CBT.

A review of four studies on the effectiveness of mindfulness-based cognitive therapy (MBCT), a recently developed class-based program designed to prevent relapse, suggests that MBCT may have an additive effect when provided with the usual care in patients who have had three or more depressive episodes, although the usual care did not include antidepressant treatment or any psychotherapy, and the improvement observed may have reflected non-specific or placebo effects. Of note, although Mindfulness-based cognitive therapy for depression prevented relapse of future depressive episodes, there is no research on whether it can cause the remission of a current depressive episode.

Interpersonal psychotherapy (IPT) focuses on the social and interpersonal triggers that may cause depression. There is evidence that it is an effective treatment for depression. Here, the therapy takes a fairly structured course (often 12 sessions, as in the original research versions) as in the case with CBT; however, the focus is on relationships with others. Unlike family therapy, IPT is an individual format, so it is possible to work on interpersonal themes even if other family members do not come to the session. Therapy can be used to help a person develop or improve interpersonal skills in order to allow him or her to communicate more effectively and reduce stress. In a meta-analysis of 16 studies and 4,356 patients, the average improvement in depressive symptoms was an effect size of d = 0.63 (95% CI, 0.36 to 0.90). IPT combined with pharmacotherapy was more effective in preventing relapse than pharmacotherapy alone, number needed to treat = 7.63.

Psychoanalysis, a school of thought founded by Sigmund Freud that emphasizes the resolution of unconscious mental conflicts, is used by its practitioners to treat clients presenting with major depression. A more widely practiced technique, called psychodynamic psychotherapy, is loosely based on psychoanalysis and has an additional social and interpersonal focus. In a meta-analysis of three controlled trials, psychodynamic psychotherapy was found to be as effective as medication for mild to moderate depression.

Shared Care

Shared decision making is an approach whereby patients and clinicians freely share important evidence when tasked with decision making and where patients are guided to consider the best available options to make an informed decision. The principles are well documented, but there is a gap in that it’s hard to apply them in routine clinical practice. The steps have been simplified into five steps. The first step is seeking patient participation in that the health practitioner is tasked with communicating existing choices and therefore inviting them to the decision making process. The next step involves assisting the patient to explore and compare the treatment options by a critical analysis of the risks and benefits. The third step involves the assessment of the patient’s values and what they prefer taking to account what is of paramount urgency to the patient. Step 4 involves decision making where the patient and the practitioner make a conclusive decision on the best option and arrange for subsequent follow up meetings. Finally, the fifth step involves the analysis of the patient’s decision’. Five steps for you and your patients to work together to make the best possible health care decisions. The step involves monitoring of the degree of implementation, overcoming of barriers of decision implantation consequently the decisions need to be revisited and optimised thus ensuring the decision has a positive impact on health outcomes its success relies on the ability of the health practitioner to create a good interpersonal relationship with the patient.

Depression still remains a major problem in the US whereby statistics have it that 16 million people were affected in the year 2017. The depression is multifactorial and has been on the increase due to societal pressure, genetic association and increase in use of drugs. incorporation of nursing in management of depression may seem important in that nursing holds a pivotal role in health care delivery where they are the health practitioners that have been trained to be versatile from clinical to psychological care. Their incorporation in shared decision making in treating depression may be important as nurses are known to have the best interpersonal relationship with the patients thus a better collaborative model can be achieved due to this fact. With this in mind, the nurses may serve to administer drugs in management, prepare and maintain the patient’s records, interaction with other care staff to achieve optimum care, and organising therapy sessions. In a study another study concerning shared decision-making interventions for people with mental health conditions there were no overt benefits that were discovered and the called for further research in this area. Another study found that it is important to begin the dissemination and implementation of SDM as they proved that it has benefits in healthcare especially in mental health care and has received social and government support and however transitioning to SDM has proven to be an uphill task. It has been suggested that SDM is of importance in demonstrating patient preferences in decision making when there is no clear approach to treatment. In addition, numerous tools can be used to make the decision making the process easier these include the Controlled Preferences Scale that informs clinicians on how to actively involve patients

Commentators suggest that providers need to embrace shared decision making by making sure that patients participate actively in their management thus enabling the success of the model.

Medication

To find the most effective pharmaceutical drug treatment, the dosages of medications must often be adjusted, different combinations of antidepressants tried, or antidepressants changed. Norepinephrine reuptake inhibitor (NRIs) can be used as antidepressants. Selective serotonin reuptake inhibitors (SSRIs), such as sertraline (Zoloft, Lustral), escitalopram (Lexapro, Cipralex), fluoxetine (Prozac), paroxetine (Seroxat), and citalopram, are the primary medications considered, due to their relatively mild side effects and broad effect on the symptoms of depression and anxiety, as well as reduced risk in overdose, compared to their older tricyclic alternatives. Those who do not respond to the first SSRI tried can be switched to another. If sexual dysfunction is present prior to the onset of depression, SSRIs should be avoided. Another popular option is to switch to the atypical antidepressant bupropion (Wellbutrin) or to add bupropion to the existing therapy; this strategy is possibly more effective. It is not uncommon for SSRIs to cause or worsen insomnia; the sedating noradrenergic and specific serotonergic antidepressant (NaSSA) antidepressant mirtazapine (Zispin, Remeron) can be used in such cases. CBT for Insomnia can also help to alleviate the insomnia without additional medication. Venlafaxine (Effexor) from the SNRI class may be moderately more effective than SSRIs; however, it is not recommended as a first-line treatment because of the higher rate of side effects, and its use is specifically discouraged in children and adolescents. Fluoxetine is the only antidepressant recommended for people under the age of 18, though, if a child or adolescent patient is intolerant to fluoxetine, another SSRI may be considered. Evidence of effectiveness of SSRIs in those with depression complicated by dementia is lacking.

Tricyclic antidepressants (TCAs) have more side effects than SSRIs (but less sexual dysfunctions) and are usually reserved for the treatment of inpatients, for whom the tricyclic antidepressant amitriptyline, in particular, appears to be more effective. A different class of antidepressants, the monoamine oxidase inhibitors, have historically been plagued by questionable efficacy (although early studies used dosages now considered too low) and life-threatening adverse effects. They are still used only rarely, although newer agents of this class (RIMA), with a better side effect profile, have been developed.

In older patients TCAs and SSRIs are of the same efficacy. However, there are differences between TCA related antidepressants and classical TCAs in terms of side effect profiles and withdrawal when compared to SSRIs.

There is evidence a prominent side-effect of antidepressants, emotional blunting, is confused with a symptom of depression itself. The cited study, according to Professor Linda Gask was: ‘funded by a pharmaceutical company (Servier) and two of its authors are employees of that company’, which may bias the results. The study authors’ note: “emotional blunting is reported by nearly half of depressed patients on antidepressants and that it appears to be common to all monoaminergic antidepressants not only SSRIs”. Additionally, they note: “The OQuESA scores are highly correlated with the HAD depression score; emotional blunting cannot be described simply as a side-effect of antidepressant, but also as a symptom of depression…More emotional blunting is associated with a poorer quality of remission…”

Acetyl-l-Carnitine

Acetylcarnitine levels were lower in depressed patients than controls and in rats it causes rapid antidepressant effects through epigenetic mechanisms. A systematic review and meta-analysis of 12 randomised controlled trials found “supplementation significantly decreases depressive symptoms compared with placebo/no intervention, while offering a comparable effect with that of established antidepressant agents with fewer adverse effects.”

Zinc

A 2012 cross-sectional study found an association between zinc deficiency and depressive symptoms among women, but not men, and a 2013 meta-analysis of 17 observational studies found that blood zinc concentrations were lower in depressed subjects than in control subjects. A 2012 meta-analysis found that zinc supplementation as an adjunct to antidepressant drug treatment significantly lowered depressive symptom scores of depressed patients. The potential mechanisms underlying the association between low serum zinc and depression remain unclear, but may involve the regulation of neurotransmitter, endocrine and neurogenesis pathways. Zinc supplementation has been reported to improve symptoms of ADHD and depression. A 2013 review found that zinc supplementation may be an effective treatment in major depression.

Magnesium

Many studies have found an association between magnesium intake and depression. Magnesium was lower in serum of depressed patients than controls. One trial found magnesium chloride to be effective for depression in seniors with type 2 diabetes while another trial found magnesium citrate decreased depression in patients with fibromyalgia. One negative trial used magnesium oxide, which is poorly absorbed. A randomised, open-label study found that consumption of magnesium chloride for 6 weeks resulted in a clinically significant net improvement in depression, and that effects were observed within 2 weeks.

Augmentation

Physicians often add a medication with a different mode of action to bolster the effect of an antidepressant in cases of treatment resistance; a 2002 large community study of 244,859 depressed Veterans Administration patients found that 22% had received a second agent, most commonly a second antidepressant. Lithium has been used to augment antidepressant therapy in those who have failed to respond to antidepressants alone. Furthermore, lithium dramatically decreases the suicide risk in recurrent depression. Addition of atypical antipsychotics when the patient has not responded to an antidepressant is also known to increase the effectiveness of antidepressant drugs, albeit at the cost of more frequent and potentially serious side effects. There is some evidence for the addition of a thyroid hormone, triiodothyronine, in patients with normal thyroid function. Stephen M. Stahl, renowned academician in psychopharmacology, has stated resorting to a dynamic psychostimulant, in particular, d-amphetamine is the “classical augmentation strategy for treatment-refractory depression”. However, the use of stimulants in cases of treatment-resistant depression is relatively controversial.

Efficacy of Medication and Psychotherapy

Antidepressants are statistically superior to placebo but their overall effect is low-to-moderate. In that respect they often did not exceed the National Institute for Health and Clinical Excellence (NICE) criteria for a “clinically significant” effect. In particular, the effect size was very small for moderate depression but increased with severity, reaching “clinical significance” for very severe depression. These results were consistent with the earlier clinical studies in which only patients with severe depression benefited from either psychotherapy or treatment with an antidepressant, imipramine, more than from the placebo treatment. Despite obtaining similar results, the authors argued about their interpretation. One author concluded that there “seems little evidence to support the prescription of antidepressant medication to any but the most severely depressed patients, unless alternative treatments have failed to provide benefit.” The other author agreed that “antidepressant ‘glass’ is far from full” but disagreed “that it is completely empty”. He pointed out that the first-line alternative to medication is psychotherapy, which does not have superior efficacy.

Antidepressants in general are as effective as psychotherapy for major depression, and this conclusion holds true for both severe and mild forms of MDD. In contrast, medication gives better results for dysthymia. The subgroup of SSRIs may be slightly more efficacious than psychotherapy. On the other hand, significantly more patients drop off from the antidepressant treatment than from psychotherapy, likely because of the side effects of antidepressants. Successful psychotherapy appears to prevent the recurrence of depression even after it has been terminated or replaced by occasional “booster” sessions. The same degree of prevention can be achieved by continuing antidepressant treatment.

Two studies suggest that the combination of psychotherapy and medication is the most effective way to treat depression in adolescents. Both TADS (Treatment of Adolescents with Depression Study) and TORDIA (Treatment of Resistant Depression in Adolescents) showed very similar results. TADS resulted in 71% of their teen subjects having “much” or “very much” improvement in mood over the 61% with medication alone and 43% with CBT alone. Similarly, TORDIA showed a 55% improvement with CBT and drugs versus a 41% with drug therapy alone. However, a more recent meta-analysis of 34 trials of 14 drugs used with children and adolescents found that only fluoxetine produced significant benefit compared to placebo, with a medium sized effect (standardize mean difference = .5).

Treatment Resistance

The risk factors for treatment resistant depression are: the duration of the episode of depression, severity of the episode, if bipolar, lack of improvement in symptoms within the first couple of treatment weeks, anxious or avoidant and borderline comorbidity and old age. Treatment resistant depression is best handled with a combination of conventional antidepressant together with atypical antipsychotics. Another approach is to try different antidepressants. It is inconclusive which approach is superior. Treatment resistant depression can be misdiagnosed if subtherapeutic doses of antidepressants is the case, patient nonadherence, intolerable adverse effects or their thyroid disease or other conditions is misdiagnosed as depression.

Experimental Treatments

Chromium

Clinical and experimental studies have reported antidepressant activity of chromium particularly in atypical depression, characterised by increased appetite and carbohydrate craving.

Essential Fatty Acids

A 2015 Cochrane Collaboration review found insufficient evidence with which to determine if omega-3 fatty acid has any effect on depression. A 2016 review found that if trials with formulations containing mostly eicosapentaenoic acid (EPA) are separated from trials using formulations containing docosahexaenoic acid (DHA), it appeared that EPA may have an effect while DHA may not, but there was insufficient evidence to be sure.

Creatine

The amino acid creatine, commonly used as a supplement to improve the performance of bodybuilders, has been studied for its potential antidepressant properties. A double-blinded, placebo-controlled trial focusing on women with major depressive disorder found that daily creatine supplementation adjunctive to escitalopram was more effective than escitalopram alone. Studies on mice have found that the antidepressant effects of creatine can be blocked by drugs that act against dopamine receptors, suggesting that the drug acts on dopamine pathways.

Dopamine Receptor Agonist

Some research suggests dopamine receptor agonist may be effective in treating depression, however studies are few and results are preliminary.

Inositol

Inositol, an alcohol sugar found in fruits, beans grains and nuts may have antidepressant effects in high doses. Inositol may exert its effects by altering intracellular signalling.

Ketamine

Research on the antidepressant effects of ketamine infusions at subanaesthetic doses has consistently shown rapid (4 to 72 hours) responses from single doses, with substantial improvement in mood in the majority of patients and remission in some. However, these effects are often short-lived, and attempts to prolong the antidepressant effect with repeated doses and extended (“maintenance”) treatment have resulted in only modest success.

N-Acetylcysteine

A systematic review and meta-analysis of 5 studies found that N-Acetylcysteine reduces depressive symptoms more than placebo and has good tolerability. N-Acetylecysteine may exert benefits as a precursor to the antioxidant glutathione, thus modulating glutamatergic, neurotropic, and inflammatory pathways.

St John’s Wort

A 2008 Cochrane Collaboration meta-analysis concluded that:

“The available evidence suggests that the hypericum extracts tested in the included trials a) are superior to placebo in patients with major depression; b) are similarly effective as standard antidepressants; c) and have fewer side effects than standard antidepressants. The association of country of origin and precision with effects sizes complicates the interpretation.”

The United States National Centre for Complementary and Integrative Health advice is that “St. John’s wort may help some types of depression, similar to treatment with standard prescription antidepressants, but the evidence is not definitive.” and warns that “Combining St. John’s wort with certain antidepressants can lead to a potentially life-threatening increase of serotonin, a brain chemical targeted by antidepressants. St. John’s wort can also limit the effectiveness of many prescription medicines.”

Rhodiola Rosea

A 2011 review reported Rhodiola rosea “is an adaptogen plant that can be especially helpful in treating asthenic or lethargic depression, and may be combined with conventional antidepressants to alleviate some of their common side effects.” A 6 week double-blind, placebo-controlled, randomised study with 89 patients with mild to moderate depression found that R. rosea statistically significantly reduced depression symptoms, and no side effects were reported.

Saffron

A 2013 meta-analysis found that saffron supplementation significantly reduced depression symptoms compared to placebo, and both saffron supplementation and the antidepressant groups were similarly effective in reducing depression symptoms. A 2015 meta-analysis supported the “efficacy of saffron as compared to placebo in improving the following conditions: depressive symptoms (compared to anti-depressants and placebo), premenstrual symptoms, and sexual dysfunction. In addition, saffron use was also effective in reducing excessive snacking behavior.” The antidepressant effect of saffron stigma extracts may be mediated via its components safranal and crocin: “crocin may act via the uptake inhibition of dopamine and norepinephrine, and safranal via serotonin.” Therapeutic doses of saffron exhibits no significant toxicity in both clinical and experimental investigations.

SAMe

S-Adenosyl methionine (SAMe) is available as a prescription antidepressant in Europe and an over-the-counter dietary supplement in the US. Evidence from 16 clinical trials with a small number of subjects, reviewed in 1994 and 1996 suggested it to be more effective than placebo and as effective as standard antidepressant medication for the treatment of major depression.

Tryptophan and 5-HTP

The amino acid tryptophan is converted into 5-hydroxytryptophan (5-HTP) which is subsequently converted into the neurotransmitter serotonin. Since serotonin deficiency has been recognized as a possible cause of depression, it has been suggested that consumption of tryptophan or 5-HTP may therefore improve depression symptoms by increasing the level of serotonin in the brain. 5-HTP and tryptophan are sold over the counter in North America, but requires a prescription in Europe. The use of 5-HTP instead of tryptophan bypasses the conversion of tryptophan into 5-HTP by the enzyme tryptophan hydroxylase, which is the rate-limiting step in the synthesis of serotonin, and 5-HTP easily crosses the blood–brain barrier unlike tryptophan, which requires a transporter.

Small studies have been performed using 5-HTP and tryptophan as adjunctive therapy in addition to standard treatment for depression. While some studies had positive results, they were criticised for having methodological flaws, and a more recent study did not find sustained benefit from their use. The safety of these medications has not been well studied. Due to the lack of high quality studies, preliminary nature of studies showing effectiveness, the lack of adequate study on their safety, and reports of Eosinophilia-myalgia syndrome from contaminated tryptophan in 1989 and 1990, the use of tryptophan and 5-HTP is not highly recommended or thought to be clinically useful.

Medical Devices

A variety of medical devices are in use or under consideration for treatment of depression including devices that offer electroconvulsive therapy, vagus nerve stimulation, repetitive transcranial magnetic stimulation, and cranial electrotherapy stimulation. The use of such devices in the United States requires approval by the US Food and Drug Administration (FDA) after field trials. In 2010 an FDA advisory panel considered the question of how such field trials should be managed. Factors considered were whether drugs had been effective, how many different drugs had been tried, and what tolerance for suicides should be in field trials.

Electroconvulsive Therapy

Electroconvulsive therapy (ECT) is a standard psychiatric treatment in which seizures are electrically induced in patients to provide relief from psychiatric illnesses. ECT is used with informed consent as a last line of intervention for major depressive disorder. Among the elderly, who often experience depression, the efficacy of ECT is difficult to determine due to the lack of trials comparing ECT to other treatments.

A round of ECT is effective for about 50% of people with treatment-resistant major depressive disorder, whether it is unipolar or bipolar. Follow-up treatment is still poorly studied, but about half of people who respond, relapse with twelve months.

Aside from effects in the brain, the general physical risks of ECT are similar to those of brief general anaesthesia. Immediately following treatment, the most common adverse effects are confusion and memory loss. ECT is considered one of the least harmful treatment options available for severely depressed pregnant women.

A usual course of ECT involves multiple administrations, typically given two or three times per week until the patient is no longer suffering symptoms ECT is administered under anaesthetic with a muscle relaxant. Electroconvulsive therapy can differ in its application in three ways: electrode placement, frequency of treatments, and the electrical waveform of the stimulus. These three forms of application have significant differences in both adverse side effects and symptom remission. After treatment, drug therapy is usually continued, and some patients receive maintenance ECT.

ECT appears to work in the short term via an anticonvulsant effect mostly in the frontal lobes, and longer term via neurotrophic effects primarily in the medial temporal lobe.

Deep Brain Stimulation

The support for the use of deep brain stimulation in treatment-resistant depression comes from a handful of case studies, and this treatment is still in a very early investigational stage. In this technique electrodes are implanted in a specific region of the brain, which is then continuously stimulated. A March 2010 systematic review found that “about half the patients did show dramatic improvement” and that adverse events were “generally trivial” given the younger psychiatric patient population than with movements disorders. Deep brain stimulation is available on an experimental basis only in the United States; no systems are approved by the FDA for this use. It is available in Australia.

Repetitive Transcranial Magnetic Stimulation

Transcranial magnetic stimulation (TMS) or deep transcranial magnetic stimulation is a non-invasive method used to stimulate small regions of the brain. During a TMS procedure, a magnetic field generator, or “coil” is placed near the head of the person receiving the treatment. The coil produces small electric currents in the region of the brain just under the coil via electromagnetic induction. The coil is connected to a pulse generator, or stimulator, that delivers electric current to the coil.

TMS was approved by the FDA for treatment-resistant major depressive disorder in 2008 and as of 2014 clinical evidence supports this use. The American Psychiatric Association, the Canadian Network for Mood and Anxiety Disorders, and the Royal Australia and New Zealand College of Psychiatrists have endorsed rTMS for trMDD.

Vagus Nerve Stimulation

Vagus nerve stimulation (VNS) uses an implanted electrode and generator to deliver electrical pulses to the vagus nerve, one of the primary nerves emanating from the brain. It is an approved therapy for treatment-resistant depression in the EU and US and is sometimes used as an adjunct to existing antidepressant treatment. The support for this method comes mainly from open-label trials, which indicate that several months may be required to see a benefit. The only large double-blind trial conducted lasted only 10 weeks and yielded inconclusive results; VNS failed to show superiority over a sham treatment on the primary efficacy outcome, but the results were more favourable for one of the secondary outcomes. The authors concluded “This study did not yield definitive evidence of short-term efficacy for adjunctive VNS in treatment-resistant depression.”

Cranial Electrotherapy Stimulation

A 2014 Cochrane review found insufficient evidence to determine whether or not Cranial electrotherapy stimulation with alternating current is safe and effective for treating depression.

Transcranial Direct Current Stimulation

A 2016 meta-analysis of transcranial direct current stimulation (tDCS) reported some efficacy of tDCS in the treatment of acute depressive disorder with moderate effect size, and low efficacy in treatment-resistant depression, and that use of 2 mA current strength over 20 minutes per day over a short time span can be considered safe.

Other Treatments

Bright Light Therapy

A meta-analysis of bright light therapy commissioned by the American Psychiatric Association found a significant reduction in depression symptom severity associated with bright light treatment. Benefit was found for both seasonal affective disorder and for non-seasonal depression, with effect sizes similar to those for conventional antidepressants. For non-seasonal depression, adding light therapy to the standard antidepressant treatment was not effective. A meta-analysis of light therapy for non-seasonal depression conducted by Cochrane Collaboration, studied a different set of trials, where light was used mostly in combination with antidepressants or wake therapy. A moderate statistically significant effect of light therapy was found, with response significantly better than control treatment in high-quality studies, in studies that applied morning light treatment, and with patients who respond to total or partial sleep deprivation. Both analyses noted poor quality of most studies and their small size, and urged caution in the interpretation of their results. The short 1-2 weeks duration of most trials makes it unclear whether the effect of light therapy could be sustained in the longer term.

Exercise

The 2013 Cochrane Collaboration review on physical exercise for depression noted that, based upon limited evidence, it is moderately more effective than a control intervention and comparable to psychological or antidepressant drug therapies. Smaller effects were seen in more methodologically rigorous studies. Three subsequent 2014 systematic reviews that included the Cochrane review in their analysis concluded with similar findings: one indicated that physical exercise is effective as an adjunct treatment with antidepressant medication; the other two indicated that physical exercise has marked antidepressant effects and recommended the inclusion of physical activity as an adjunct treatment for mild-moderate depression and mental illness in general. These studies also found smaller effect sizes in more methodologically rigorous studies. All four systematic reviews called for more research in order to determine the efficacy or optimal exercise intensity, duration, and modality. The evidence for brain-derived neurotrophic factor (BDNF) in mediating some of the neurobiological effects of physical exercise was noted in one review which hypothesized that increased BDNF signalling is responsible for the antidepressant effect.

Meditation

Mindfulness meditation programs may help improve symptoms of depression, but they are no better than active treatments such as medication, exercise, and other behavioural therapies.

Music Therapy

A 2009 review found that 3 to 10 sessions of music therapy resulted in a noticeable improvement in depressive symptoms, with still greater improvement after 16 to 51 sessions.

Sleep

Depression is sometimes associated with insomnia – (difficulty in falling asleep, early waking, or waking in the middle of the night). The combination of these two results, depression and insomnia, will only worsen the situation. Hence, good sleep hygiene is important to help break this vicious circle. It would include measures such as regular sleep routines, avoidance of stimulants such as caffeine and management of sleeping disorders such as sleep apnoea.

Smoking Cessation

Quitting smoking cigarettes is associated with reduced depression and anxiety, with the effect “equal or larger than” those of antidepressant treatments.

Total/Partial Sleep Deprivation

Sleep deprivation (skipping a night’s sleep) has been found to improve symptoms of depression in 40-60% of patients. Partial sleep deprivation in the second half of the night may be as effective as an all night sleep deprivation session. Improvement may last for weeks, though the majority (50-80%) relapse after recovery sleep. Shifting or reduction of sleep time, light therapy, antidepressant drugs, and lithium have been found to potentially stabilise sleep deprivation treatment effects.

Shared Care

Shared care, when primary and specialty physicians have joint management of an individual’s health care, has been shown to alleviate depression outcomes.

What is Treatment-Resistant Depression?

Introduction

Treatment-resistant depression (TRD) is a term used in clinical psychiatry to describe a condition that affects people with major depressive disorder (MDD) who do not respond adequately to a course of appropriate antidepressant medication within a certain time.

Typical definitions of TRD vary, and they do not include a resistance to psychological therapies. Inadequate response has traditionally been defined as no clinical response whatsoever (e.g. no improvement in depressive symptoms). However, many clinicians consider a response inadequate if the person does not achieve full remission of symptoms. People with treatment-resistant depression who do not adequately respond to antidepressant treatment are sometimes referred to as pseudoresistant. Some factors that contribute to inadequate treatment are: early discontinuation of treatment, insufficient dosage of medication, patient noncompliance, misdiagnosis, and concurrent psychiatric disorders. Cases of treatment-resistant depression may also be referred to by which medications people with TRD are resistant to (e.g.: SSRI-resistant). In TRD adding further treatments such as psychotherapy, lithium, or aripiprazole is weakly supported as of 2019.

Refer to Atypical Depression and Masked Depression.

Risk Factors

Comorbid Psychiatric Disorders

Comorbid psychiatric disorders commonly go undetected in the treatment of depression. If left untreated, the symptoms of these disorders can interfere with both evaluation and treatment. Anxiety disorders are one of the most common disorder types associated with treatment-resistant depression. The two disorders commonly co-exist, and have some similar symptoms. Some studies have shown that patients with both MDD and panic disorder are the most likely to be nonresponsive to treatment. Substance abuse may also be a predictor of treatment-resistant depression. It may cause depressed patients to be noncompliant in their treatment, and the effects of certain substances can worsen the effects of depression. Other psychiatric disorders that may predict treatment-resistant depression include attention deficit hyperactivity disorder, personality disorders, obsessive compulsive disorder, and eating disorders.

Comorbid Medical Disorders

Some people who are diagnosed with treatment-resistant depression may have an underlying undiagnosed health condition that is causing or contributing to their depression. Endocrine disorders like hypothyroidism, Cushing’s disease, and Addison’s disease are among the most commonly identified as contributing to depression. Others include diabetes, coronary artery disease, cancer, HIV, and Parkinson’s disease. Another factor is that medications used to treat comorbid medical disorders may lessen the effectiveness of antidepressants or cause depression symptoms.

Features of Depression

People with depression who also display psychotic symptoms such as delusions or hallucinations are more likely to be treatment resistant. Another depressive feature that has been associated with poor response to treatment is longer duration of depressive episodes. Finally, people with more severe depression and those who are suicidal are more likely to be nonresponsive to antidepressant treatment.

Treatment

There are three basic categories of drug treatment that can be used when a medication course is found to be ineffective. One option is to switch the patient to a different medication. Another option is to add a medication to the patient’s current treatment. This can include combination therapy: the combination of two different types of antidepressants, or augmentation therapy: the addition of a non-antidepressant medication that may increase the effectiveness of the antidepressant.

Medication

Antidepressants

Dose Increase

Increasing the dosage of an antidepressant is a common strategy to treat depression that does not respond after adequate treatment duration. Practitioners who use this strategy will usually increase the dose until the person reports intolerable side effects, symptoms are eliminated, or the dose is increased to the limit of what is considered safe.

Switching Antidepressants

Studies have shown a wide variability in the effectiveness of switching antidepressants, with anywhere from 25-70% of people responding to a different antidepressant. There is support for the effectiveness of switching people to a different SSRI; 50% of people that were non-responsive after taking one SSRI were responsive after taking a second type. Switching people with TRD to a different class of antidepressants may also be effective. People who are non-responsive after taking an SSRI may respond to moclobemide or tricyclic antidepressant, bupropion or an MAOI.

However, the more antidepressants an individual had already tried, the less likely they were to benefit from a new antidepressant trial.

Some off label antidepressants are low dose ketamine and highly serotonergic catecholamines (including very controlled use of MDMA in the treatment of PTSD and crippling depression/anxiety). For lethargic syndromes, dysthymia, or caffeine-resistant amotivation, a dopaminergic stimulant such as methlyphenidate, or even 2.5 mg dextroamphetamine can be helpful.

Primarily dopaminergic or norepinephrine releasing stimulants, in low doses, have been used especially in the past, or in conjunction with a multidisciplinary therapy approach, although more targeted and “mild” agents, including modafinil and atomoxetine are considered first line for both childhood and adult lethargy and inattention disorders, due to their virtually non-existent abuse potential (limited to one or two cases per 10,000), and higher selectivity, safety, and thus slightly broader therapeutic index. When depression is related or co-morbid to an inattention disorder, often ADHD, then both can be carefully managed with the same first line stimulant medication, typically both methylphenidate and lisdexamphetamine.

Other Medications

Medications that have been shown to be effective in people with treatment-resistant depression include lithium, triiodothyronine, benzodiazepines, atypical antipsychotics, and stimulants. Adding lithium may be effective for people taking some types of antidepressants; it does not appear to be effective in patients taking SSRIs. Triiodothyroxine (T3) is a type of thyroid hormone and has been associated with improvement in mood and depression symptoms. Benzodiazepines may improve treatment-resistant depression by decreasing the adverse side effects caused by some antidepressants and therefore increasing patient compliance. Since the entry of olanzapine into psychopharmacology, anecdotal evidence suggests that many psychiatrists have been adding low dose olanzapine to antidepressants and other atypical antipsychotics such as aripiprazole and quetiapine. Eli Lilly, the company that sells both olanzapine and fluoxetine individually, has also released a combination formulation which contains olanzapine and fluoxetine in a single capsule. Some low to moderate quality evidence points to success in the short term (8-12 weeks) using mianserin (or antipsychotics cariprazine, olanzapine, quetiapine or ziprasidone) to augment antidepressant medications.

These have shown promise in treating refractory depression but come with serious side effects. Stimulants such as amphetamines and methylphenidate have also been tested with positive results but have potential for abuse. However, stimulants have been shown to be effective for the unyielding depressed combined lacking addictive personality traits or heart problems.

Ketamine has been tested as a rapid-acting antidepressant for treatment-resistant depression in bipolar disorder, and major depressive disorder.

Research

A 2016 placebo randomised controlled trial (RCT) evaluated the rapid antidepressant effects of the psychedelic ayahuasca in treatment-resistant depression with positive outcome.

Physical Psychiatric Treatments

Electroconvulsive Therapy

Electroconvulsive therapy is generally only considered as a treatment option in severe cases of treatment-resistant depression. It is used when medication has repeatedly failed to improve symptoms, and usually when the patient’s symptoms are so severe that they have been hospitalised. Electroconvulsive therapy has been found to reduce thoughts of suicide and relieve depressive symptoms. It is associated with an increase in glial cell line derived neurotrophic factor.

rTMS

rTMS (repetitive transcranial magnetic stimulation) is gradually becoming recognised as a valuable therapeutic option in treatment-resistant depression. A number of randomised placebo-controlled trials have compared real versus sham rTMS. These trials have consistently demonstrated the efficacy of this treatment against major depression. There have also been a number of meta-analyses of RCTs confirming the efficacy of rTMS in treatment-resistant major depression, as well as naturalistic studies showing its effectiveness in “real world” clinical settings.

dTMS

dTMS (deep transcranial magnetic stimulation) is a continuation of the same idea as rTMS, but with the hope that deeper stimulation of subcortical areas of the brain leads to increased effect. A 2015 systematic review and health technology assessment found lacking evidence in order to recommend the method over either ECT or rTMS because so few studies had been published.

Psychotherapy

There is sparse evidence on the effectiveness of psychotherapy in cases of treatment-resistant depression. However, a review of the literature suggests that it may be an effective treatment option. Psychotherapy may be effective in people with TRD because it can help relieve stress that may contribute to depressive symptoms.

A Cochrane systematic review has shown that psychological therapies (including cognitive behavioural therapy, dialectal behavioural therapy, interpersonal therapy and intensive short-term dynamic psychotherapy) added to usual care (with antidepressants) can be beneficial for depressive symptoms and for response and remission rates over the short term (up to six months) for patients with TRD. Medium‐ (7-12 months) and long‐term (longer than 12 months) effects seem similarly beneficial. Psychological therapies added to usual care (antidepressants) seem as acceptable as usual care alone.

Outcomes

Treatment-resistant depression is associated with more instances of relapse than depression that is responsive to treatment. One study showed that as many as 80% of people with TRD who needed more than one course of treatment relapsed within a year. Treatment-resistant depression has also been associated with lower long-term quality of life.

Another study saw just 8 of 124 patients in remission after two years of regular treatment with therapy and medicines.

Epidemiology

Treatment-resistance is relatively common in people with MDD. Rates of total remission following antidepressant treatment are only 50.4%. In cases of depression treated by a primary care physician, 32% of people partially responded to treatment and 45% did not respond at all.

What is Masked Depression?

Introduction

Masked depression (MD) was a proposed form of atypical depression in which somatic symptoms or behavioural disturbances dominate the clinical picture and disguise the underlying affective disorder.

The concept (as of March 2021) is not currently supported by the mental health profession.

Refer to Atypical Depression and Treatment-Resistant Depression.

Clinical Manifestations

Somatic manifestations of MD are distinguished by an extreme diversity and include headaches, back pain, abdominal pain etc. Pathological behaviour masking depression may take the form of compulsive gambling, compulsive work, changes in arousal or orgasmic function, decreased libido or, on the contrary, impulsive sexual behaviour, alcoholism, or drug addiction.

Dispute about the Concept

MD has been variously described as “depression sine (without) depression” (K. Schneider, 1925), “latent” depression (Lange J., 1928), “vegetative depression” (R. Lemke, 1949) “hidden” or “masked” depression (Lopez Ibor J.J. [es], 1972; Kielholz J.J., 1983; Pichot P.; Hasson J., 1973), “larvate” or “somatisation depression” (Gayral L., 1972), “depressive equivalents” etc. Most investigators, especially those in the German-speaking countries, assumed masked depression (German: die larvierte Depression) to be endogenous depression. The term was largely used in the 1970s and 1980s, but at the end of the 20th century there was a decline in interest in the study of masked depression. Today this diagnosis does not play a significant clinical or scientific role.

Epidemiology

MD is supposed to be a common clinical phenomenon. According to some authors, masked depression is as frequent as overt depression. Although masked depression can be found at any age, it has been observed more commonly after mid-life.

Making the diagnosis and the management of MD in clinical practice are complicated by the fact that the individual who has MD is unaware of their mental illness. Patients with MD are reluctant to associate their physical symptoms with an affective disorder and refuse mental health care. As a rule, these patients attribute their disturbances to physical illness, seek medical care for them, and report only somatic complaints to their medical professional, with the consequence that many of such depressions are not recognised or are misdiagnosed and mistreated Estimates of depressed patients who are correctly identified and treated range from 5% to 60%. Recent data show that about 10% of people who consult a medical professional for any reason originally suffer from affective disorders disguised by physical symptoms.

Official Diagnostic Status

Current classifications: ICD-10 and DSM-5 do not contain the term “masked depression”.

Some Ukrainian psychiatrists claim that MD is to be qualified as “depression with somatic symptoms” (F 3x.01), according to ICD-10. This means that those who struggle with masked depression often have more physical symptoms such as back pain, abdominal pain, headaches, and even pain during sexual activity or painful periods.

For those with more clinical depression, while they still may have physical symptoms, their symptoms are usually more mental or emotional. This includes feelings of helplessness, extreme and/or persisting sadness, numbness, tiredness, drowsiness, exhaustion, and even suicidal thoughts or feelings.

Diagnostic Criteria

Affective disorders in patients with MD can only be detected by means of a clinician-administered diagnostic interview. Organic exclusion rules and other criteria are used in making the diagnosis of MD. Some physical symptoms of masked depression include general aches, pains including headache, backache, musculoskeletal aches, and other nonpainful symptoms such as changes in appetite and libido, lack of energy, sleep disturbance, dizziness, palpitations, dyspnoea, and gastrointestinal tract disturbances.

What is Atypical Depression?

Introduction

Atypical depression as it has been known in the DSM IV, is depression that shares many of the typical symptoms of the psychiatric syndromes of major depression or dysthymia but is characterised by improved mood in response to positive events.

In contrast to atypical depression, people with melancholic depression generally do not experience an improved mood in response to normally pleasurable events. Atypical depression also features significant weight gain or an increased appetite, hypersomnia, a heavy sensation in the limbs, and interpersonal rejection sensitivity that results in significant social or occupational impairment.

Despite its name, “atypical” depression does not mean it is uncommon or unusual. The reason for its name is twofold: it was identified with its “unique” symptoms subsequent to the identification of melancholic depression and its responses to the two different classes of antidepressants that were available at the time were different from melancholic depression (i.e. monoamine oxidase inhibitors (MAOIs) had clinically significant benefits for atypical depression, while tricyclics did not).

Atypical depression is four times more common in females than in males. Individuals with atypical features tend to report an earlier age of onset (e.g. while in high school) of their depressive episodes, which also tend to be more chronic and only have partial remission between episodes. Younger individuals may be more likely to have atypical features, whereas older individuals may more often have episodes with melancholic features. Atypical depression has high comorbidity of anxiety disorders, carries more risk of suicidal behaviour, and has distinct personality psychopathology and biological traits.

Atypical depression is more common in individuals with bipolar I, bipolar II, cyclothymia and seasonal affective disorder. Depressive episodes in bipolar disorder tend to have atypical features, as does depression with seasonal patterns.

Refer to Masked Depression and Treatment-Resistant Depression.

Pathophysiology

Significant overlap between atypical and other forms of depression have been observed, though studies suggest there are differentiating factors within the various pathophysiological models of depression. In the endocrine model, evidence suggests the HPA axis is hyperactive in melancholic depression, and hypoactive in atypical depression. Atypical depression can be differentiated from melancholic depression via verbal fluency tests and psychomotor speed tests. Although both show impairment in several areas such as visuospatial memory and verbal fluency, melancholic patients tend to show more impairment than atypical depressed patients.

Furthermore, regarding the inflammatory theory of depression, inflammatory blood markers (cytokines) appear to be more elevated in atypical depression when compared to non-atypical depression.

Diagnosis

The diagnosis of atypical depression is based on the criteria stated in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). The DSM-5 defines atypical depression as a subtype of major depressive disorder that presents with “atypical features”, characterised by:

  • Mood reactivity (i.e., mood brightens in response to actual or potential positive events)
  • At least two of the following:
    • Significant weight gain or increase in appetite (hyperphagia);
    • Hypersomnia (sleeping too much, as opposed to the insomnia present in melancholic depression);
    • Leaden paralysis (i.e., heavy feeling resulting in difficulty moving the arms or legs);
    • Long-standing pattern of interpersonal rejection sensitivity (not limited to episodes of mood disturbance) that results in significant social or occupational impairment.

Criteria are not met for With Melancholic Features or With Catatonic Features during the same episode.

Treatment

Due to the differences in clinical presentation between atypical depression and melancholic depression, studies were conducted in the 1980s and 1990s to assess the therapeutic responsiveness of the available antidepressant pharmacotherapy in this subset of patients. Currently, antidepressants such as SSRIs, SNRIs, NRIs, and mirtazapine are considered the best medications to treat atypical depression due to efficacy and fewer side effects than previous treatments. Bupropion, a norepinephrine reuptake inhibitor, may be uniquely suited to treat the atypical depression symptoms of lethargy and increased appetite in adults. Modafinil is sometimes used successfully as an off-label treatment option.

Before the year 2000, monoamine oxidase inhibitors (MAOIs) were shown to be of superior efficacy compared to other antidepressants for the treatment of atypical depression, and were used as first-line treatment for this clinical presentation. This class of medication fell in popularity with the advent of the aforementioned selective agents, due to concerns of interaction with tyramine-rich foods (such as some aged cheese, certain types of wine, tap beer and fava beans) causing a hypertensive crisis and some – but not all – sympathomimetic drugs, as well as the risk of serotonin syndrome when concomitantly used with serotonin reuptake agents. Despite these concerns, they are still used in treatment-resistant cases, when other options have been exhausted, and usually show greater rates of remission compared to previous pharmacotherapies. They are also generally better tolerated by many patients. There are also newer selective and reversible MAOIs, such as moclobemide, which carry a much lower risk of tyramine potentiation and have fewer interactions with other drugs.

Tricyclic antidepressants (TCAs) were also used prior to the year 2000 for atypical depression, but were not as efficacious as MAOIs, and have fallen out of favour with prescribers due to the less tolerable side effects of TCAs and more adequate therapies being available.

Some evidence supports that psychotherapy such as cognitive behavioural therapy (CBT) has equal efficacy to MAOI. These are talk therapy sessions with psychiatrists to help the individual identify troubling thoughts or experiences that may have affected their mental state, and develop corresponding coping mechanisms for each identified issue.

No robust guidelines for the treatment of atypical depression currently exist.

Epidemiology

True prevalence of atypical depression is difficult to determine. Several studies conducted in patients diagnosed with a depressive disorder show that about 40% exhibit atypical symptoms, with four times more instances found in female patients. Research also supports that atypical depression tends to have an earlier onset, with teenagers and young adults more likely to exhibit atypical depression than older patients. Patients with atypical depression have shown to have higher rates of neglect and abuse in their childhood as well as alcohol and drug disorders in their family. Overall, rejection sensitivity is the most common symptom, and due to some studies forgoing this criterion, there is concern for underestimation of prevalence.

Research

In general, atypical depression tends to cause greater functional impairment than other forms of depression. Atypical depression is a chronic syndrome that tends to begin earlier in life than other forms of depression – usually beginning in the teenage years. Similarly, patients with atypical depression are more likely to suffer from personality disorders and anxiety disorders such as borderline personality disorder, avoidant personality disorder, generalised anxiety disorder, obsessive-compulsive disorder, and bipolar disorder.

Recent research suggests that young people are more likely to suffer from hypersomnia while older people are more likely to suffer from polyphagia.

Medication response differs between chronic atypical depression and acute melancholic depression. Some studies suggest that the older class of antidepressants, MAOIs, may be more effective at treating atypical depression. While the more modern SSRIs and SNRIs are usually quite effective in this illness, the tricyclic antidepressants typically are not. The wakefulness-promoting agent modafinil has shown considerable effect in combating atypical depression, maintaining this effect even after discontinuation of treatment. Antidepressant response can often be enhanced with supplemental medications, such as buspirone, bupropion, or aripiprazole. Psychotherapy, whether alone or in combination with medication, is also an effective treatment in individual and group settings.