Tag: Hallucination

What is Paraphrenia?

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Introduction

Paraphrenia is a mental disorder characterised by an organised system of paranoid delusions with or without hallucinations (the positive symptoms of schizophrenia) and without deterioration of intellect or personality (its negative symptom).

This disorder is also distinguished from schizophrenia by a lower hereditary occurrence, less premorbid maladjustment, and a slower rate of progression. Onset of symptoms generally occurs later in life, near the age of 60. The prevalence of the disorder among the elderly is between 0.1% and 4%.

Paraphrenia is not included in the DSM-5; psychiatrists often diagnose patients presenting with paraphrenia as having atypical psychosis, delusional disorder, psychosis not otherwise specified, schizoaffective disorders, and persistent persecutory states of older adults. Recently, mental health professionals have also been classifying paraphrenia as very late-onset schizophrenia-like psychosis.

In the Russian psychiatric manuals, paraphrenia (or paraphrenic syndrome) is the last stage of development of paranoid schizophrenia. “Systematised paraphrenia” (with systematised delusions i. e. delusions with complex logical structure) and “expansive-paranoid paraphrenia” (with expansive/grandiose delusions and persecutory delusions) are the variants of paranoid schizophrenia (F20.0). Sometimes systematised paraphrenia can be seen with delusional disorder (F22.0). The word is from Ancient Greek: παρά – beside, near + φρήν – intellect, mind.

Brief History

The term paraphrenia was originally popularised by Karl Ludwig Kahlbaum in 1863 to describe the tendency of certain psychiatric disorders to occur during certain transitional periods in life (describing paraphrenia hebetica as the insanity of the adolescence and paraphrenia senilis as the insanity of the elders.

The term was also used by Sigmund Freud for a short time starting in 1911 as an alternative to the terms schizophrenia and dementia praecox, which in his estimation did not correctly identify the underlying condition, and by Emil Kraepelin in 1912/1913, who changed its meaning to describe paraphrenia as it is understood today, as a small group of individuals that have many of the symptoms of schizophrenia with a lack of deterioration and thought disorder. Kraepelin’s study was discredited by Wilhelm Mayer in 1921 when he conducted a follow-up study using Kraepelin’s data. His study suggested that there was little to no discrimination between schizophrenia and paraphrenia; given enough time, patients presenting with paraphrenia will merge into the schizophrenic pool. However, Meyer’s data are open to various interpretations. In 1952, Roth and Morrissey conducted a large study in which they surveyed the mental hospital admissions of older patients. They characterised patients as having:

“paraphrenic delusions which… occurred in each case in the setting of a well-preserved intellect and personality, were often ‘primary’ in character, and were usually associated with the passivity failings or other volitional disturbances and hallucinations in clear consciousness pathognomonic of schizophrenia”.

In recent medicine, the term paraphrenia has been replaced by the diagnosis of “very late-onset schizophrenia-like psychosis” and has also been called “atypical psychoses, delusional disorder, psychoses not otherwise specified, schizoaffective disorders, and persistent persecutory states of older adults” by psychotherapists.[4] Current studies, however, recognize the condition as “a viable diagnostic entity that is distinct from schizophrenia, with organic factors playing a role in a significant portion of patients.”[4]

Signs and Symptoms

The main symptoms of paraphrenia are paranoid delusions and hallucinations. The delusions often involve the individual being the subject of persecution, although they can also be erotic, hypochondriacal, or grandiose in nature. The majority of hallucinations associated with paraphrenia are auditory, with 75% of patients reporting such an experience; however, visual, tactile, and olfactory hallucinations have also been reported. The paranoia and hallucinations can combine in the form of “threatening or accusatory voices coming from neighbouring houses [and] are frequently reported by the patients as disturbing and undeserved”. Patients also present with a lack of symptoms commonly found in other mental disorders similar to paraphrenia. There is no significant deterioration of intellect, personality, or habits and patients often remain clean and mostly self-sufficient. Patients also remain oriented well in time and space.

Paraphrenia is different from schizophrenia because, while both disorders result in delusions and hallucinations, individuals with schizophrenia exhibit changes and deterioration of personality whereas individuals with paraphrenia maintain a well-preserved personality and affective response.

Causes

Neurological

Paraphrenia is often associated with a physical change in the brain, such as a tumour, stroke, ventricular enlargement, or neurodegenerative process. Research that reviewed the relationship between organic brain lesions and the development of delusions suggested that “brain lesions which lead to subcortical dysfunction could produce delusions when elaborated by an intact cortex”.

Predisposing Factors

Many patients who present with paraphrenia have significant auditory or visual loss, are socially isolated with a lack of social contact, do not have a permanent home, are unmarried and without children, and have maladaptive personality traits. While these factors do not cause paraphrenia, they do make individuals more likely to develop the disorder later in life.

Diagnosis

While the diagnosis of paraphrenia is absent from recent revisions of the DSM and the ICD, many studies have recognised the condition as “a viable diagnostic entity that is distinct from schizophrenia, with organic factors playing a role in a significant portion of patients.” As such, paraphrenia is seen as being distinct from both schizophrenia and progressive dementia in old age. Ravindran (1999) developed a list of criteria for the diagnosis of paraphrenia, which agrees with much of the research done up to the time it was published.

  1. A delusional disorder of at least six months duration characterized by the following:
    1. Preoccupation with one or more semi-systematised delusions, often accompanied by auditory hallucinations.
    2. Affect notably well-preserved and appropriate. Ability to maintain rapport with others.
    3. None of:
      1. Intellectual deterioration.
      2. Visual hallucinations.
      3. Incoherence.
      4. Flat or grossly inappropriate affect.
      5. Grossly disorganised behaviour at times other than during the acute episode.
    4. Disturbance of behaviour understandable in relation to the content of the delusions and hallucinations.
    5. Only partly meets criterion A for schizophrenia. No significant organic brain disorder.

Management

Research suggests that paraphrenics respond well to antipsychotic drug therapy if doctors can successfully achieve sufficient compliance. Herbert found that Stelazine combined with Disipal was an effective treatment. It promoted the discharging of patients and kept discharged patients from being readmitted later. While behaviour therapy may help patients reduce their preoccupation with delusions, psychotherapy is not currently of primary value.

Prognosis

Individuals who develop paraphrenia have a life expectancy similar to the normal population. Recovery from the psychotic symptoms seems to be rare, and in most cases paraphrenia results in in-patient status for the remainder of the life of the patient. Patients experience a slow deterioration of cognitive functions and the disorder can lead to dementia in some cases, but this development is no greater than the normal population.

Epidemiology

Studies suggest that the prevalence of paraphrenia in the elderly population is around 2-4%.

Sex Differences

While paraphrenia can occur in both men and women, it is more common in women, even after the difference has been adjusted for life expectancies. The ratio of women with paraphrenia to men with paraphrenia is anywhere from 3:1 to 45:2.

Age

It is seen mainly in patients over the age of 60, but has been known to occur in patients in their 40s and 50s.

Personality Type and Living Situation

It is suggested that individuals who develop paraphrenia later in life have premorbid personalities, and can be described as “quarrelsome, religious, suspicious or sensitive, unsociable and cold-hearted.” Many patients were also described as being solitary, eccentric, isolated and difficult individuals; these characteristics were also long-standing rather than introduced by the disorder. Most of the traits recognised prior to the onset of paraphrenia in individuals can be grouped as either paranoid or schizoid. Patients presenting with paraphrenia were most often found to be living by themselves (either single, widowed, or divorced). There have also been reports of low marriage rate among paraphrenics and these individuals also have few or no children (possibly because of this premorbid personality).

Physical Factors

The development of paranoia and hallucinations in old age have been related to both auditory and visual impairment, and individuals with paraphrenia often present with one or both of these impairments. Hearing loss in paraphrenics is associated with early age of onset, long duration, and profound auditory loss.

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What is the Paranoia Network?

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Introduction

The Paranoia Network, founded in November 2003, is a self-help user-run organisation in Sheffield, England, for people who have paranoid or delusional beliefs.

Background

In contrast to mainstream psychiatry, that tends to see such beliefs as signs of psychopathology, the Paranoia Network promotes a philosophy of living with unusual and compelling beliefs, without necessarily pathologising them as signs of mental illness. It was partly inspired by the Hearing Voices Network’s approach to auditory hallucinations.

What would otherwise seem to be a relatively minor disagreement over theory is complicated by the fact that people diagnosed as delusional can often be detained under mental health law and treated without their consent. Therefore, many of the criticisms of the diagnosis or definition have important ethical and political implications, which often leads to heated public debate.

This page is based on the copyrighted Wikipedia article < https://en.wikipedia.org/wiki/Paranoia_Network >; it is used under the Creative Commons Attribution-ShareAlike 3.0 Unported License (CC-BY-SA). You may redistribute it, verbatim or modified, providing that you comply with the terms of the CC-BY-SA.

What is the Brief Psychiatric Rating Scale?

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Introduction

The Brief Psychiatric Rating Scale (BPRS) is a rating scale which a clinician or researcher may use to measure psychiatric symptoms such as depression, anxiety, hallucinations and unusual behaviour.

The scale is one of the oldest, most widely used scales to measure psychotic symptoms and was first published in 1962.

Brief History

The BPRS was initially developed by John E. Overall and Donald R. Gorham. It was created for the purpose of being able to quickly assess the patient’s psychiatric symptoms prior, during, or following a treatment. The items of the test were generated from conducting factor analysis on the Multidimensional Scale for Rating Psychiatric Patients and the Inpatient Multidimensional Psychiatric Scale. Sixteen factors were found from the analysis, which served as the building blocks for the BPRS. Later research in 1968 added two more factors to the BPRS, which were excitement and disorientation.

Test Format

The BPRS consists of 18 items measuring the following factors:

  1. Anxiety.
  2. Emotional withdrawal.
  3. Conceptual disorganisation.
  4. Guilt feelings.
  5. Tension.
  6. Mannerisms and posturing.
  7. Grandiosity.
  8. Depressive moods.
  9. Hostility.
  10. Suspiciousness.
  11. Hallucinatory behaviour.
  12. Motor hyperactivity.
  13. Uncooperativeness.
  14. Unusual thought content.
  15. Blunted affect.
  16. Somatic concern.
  17. Excitement.
  18. Disorientation.

It uses a seven-item Likert scale with the following values:

  • 1 = “not present”.
  • 2 = “very mild”.
  • 3 = “mild”.
  • 4 = “moderate”.
  • 5 = “moderately severe”.
  • 6 = “severe”.
  • 7 = “extremely severe”.

The test is administered in tandem with a series of interviews conducted by at least two clinicians to ensure interrater reliability of the assessment.

Usage

The BPRS is intended for use on adult psychiatric patients and has been validated for use in elderly populations. A version designed for children called the Brief Psychiatric Rating Scale Children was also developed by Overall and Betty Pfeifferbaum, with different scale structures and factors.

Further Development

An expanded version of the test was created in 1993 by D. Lukoff, Keith H. Nuechterlein, and Joseph Ventura.

This page is based on the copyrighted Wikipedia article <https://en.wikipedia.org/wiki/Brief_Psychiatric_Rating_Scale&gt;; it is used under the Creative Commons Attribution-ShareAlike 3.0 Unported License (CC-BY-SA). You may redistribute it, verbatim or modified, providing that you comply with the terms of the CC-BY-SA.

What is the Hearing Voices Movement?

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Introduction

The Hearing Voices Movement (HVM) is the name used by organisations and individuals advocating the “hearing voices approach”, an alternative way of understanding the experience of those people who “hear voices”.

In the medical professional literature, ‘voices’ are most often referred to as auditory verbal hallucinations. The movement uses the term ‘hearing voices’, which it feels is a more accurate and ‘user-friendly’ term.

The movement was instigated by Marius Romme, Sandra Escher and Patsy Hage in 1987. It challenges the notion that to hear voices is necessarily a characteristic of mental illness. Instead it regards hearing voices as a meaningful and understandable, although unusual, human variation. It therefore rejects the stigma and pathologisation of hearing voices and advocates human rights, social justice and support for people who hear voices that is empowering and recovery focused. The movement thus challenges the medical model of mental illness, specifically the validity of the schizophrenia construct.

Refer to Hearing Voices Network.

Brief History

The international Hearing Voices Movement is a prominent mental health service-user/survivor movement that promotes the needs and perspectives of experts by experience in the phenomenon of hearing voices (auditory verbal hallucinations). The main tenet of the Hearing Voices Movement is the notion that hearing voices is a meaningful human experience.

The Hearing Voices Movement regards itself and is regarded by others as being a post-psychiatric organisation. It positions itself outside of the mental health world in recognition that voices are an aspect of human difference, rather than a mental health problem. One of the main issues of concern for the Hearing Voices Movement is empowerment and human rights as outlined in its Melbourne Hearing Voices Declaration 2013 and Thessaloniki Declaration 2014.

The Hearing Voices Movement also seeks holistic health solutions to problematic and overwhelming voices that cause mental distress. Based on their research, the movement espouses that many people successfully live with their voices. In themselves voices are not seen as the problem. Rather it is the relationship the person has with their voices that is regarded as the main issue. Research indicates that mindfulness-based interventions can be beneficial for people distressed by hearing voices.

The Hearing Voices Movement has developed interventions for mental health practitioners to support people who hear voices and are overwhelmed by the experience.

Position

The position of the hearing voices movement can be summarised as follows:

  • Hearing voices is not in itself a sign of mental illness.
  • Hearing voices is part of the diversity of being a human, it is a faculty that is common (3-10% of the population will hear a voice or voices in their lifetime) and significant.
  • Hearing voices is experienced by many people who do not have symptoms that would lead to diagnosis of mental illness.
  • Hearing voices is often related to problems in life history.
  • If hearing voices causes distress, the person who hears the voices can learn strategies to cope with the experience.
  • Coping is often achieved by confronting the past problems that lie behind the experience.

Theoretical Overview

The work of Marius Romme, Sandra Escher and other researchers provides a theoretical framework for the movement. They find that:

  • Not everyone who hears voices becomes a patient. Over a third of 400 voice hearers in the Netherlands they studied had not had any contact with psychiatric services. These people either described themselves as being able to cope with their voices and/or described their voices as life enhancing.
  • Demographic (epidemiological) research carried out over the last 120 years provides evidence that there are people who hear voices in the general population (2%-6%) who are not necessarily troubled by them). Only a small minority fulfil the criteria for a psychiatric diagnosis and, of those, only a few seek psychiatric aid indicating that hearing voices in itself is not necessarily a symptom of an illness. Even more (about 8%) have peculiar delusions and do so without being ill.
  • People who cope well with their voices and those who did not, show clear differences in terms of the nature of the relationship they had with their voices.
  • People who live well with their voice experience use different strategies to manage their voices than those voice hearers who are overwhelmed by them.
  • 70% of voice hearers reported that their voices had begun after a severe traumatic or intensely emotional event such as an accident, divorce or bereavement, sexual or physical abuse, love affairs, or pregnancy. Romme and colleagues found that the onset of voice hearing amongst a patient group was preceded by either a traumatic event or an event that activated the memory of an earlier trauma.
  • Specifically, there is a high correlation between voice hearing and abuse. These findings are being substantiated further in on-going studies with voice hearing amongst children.
  • Some people who hear voices have a deep need to construct a personal understanding for their experiences and to talk to others about it without being designated as mad.

Romme, colleagues and other researchers find that people who hear voices can be helped using methods such as voice dialoguing cognitive behaviour therapy (CBT) and self-help methods.

Romme theorises a three phase model of recovery:

StartlingInitial confusion; emotional chaos, fear, helplessness and psychological turmoil.
OrganisationThe need to find meaning, arrive at some understanding and acceptance. The development of ways of coping and accommodating voices in everyday living. This task may take months or years and is marked by the attempt to enter into active negotiation with the voice(s).
StabilisationThe establishment of equilibrium, and accommodation, with the voice(s), and the consequent re-empowerment of the person.

Alternative to Medical Model of Disability

The Hearing Voices Movement disavows the medical model of disability and disapproves of the practises of mental health services through much of the Western world, such as treatment solely with medication. For example, some service users have reported negative experiences of mental health services because they are discouraged from talking about their voices as these are seen solely as symptoms of psychiatric illness. Slade and Bentall conclude that the failure to attend to hallucinatory experiences and/or have the opportunity for dialogue about them is likely to have the effect of helping to maintain them.

In Voices of Reason, Voices of Insanity, Leudar and Thomas review nearly 3,000 years of voice-hearing history. They argue that the Western World has moved the experience of hearing voices from a socially valued context to a pathologised and denigrated one. Foucault has argued that this process can generally arise when a minority perspective is at odds with dominant social norms and beliefs.

Organisation

The Hearing Voices Movement was established in 1987 by Romme and Escher, both from the Netherlands, with the formation of Stichting Weerklank (Foundation Resonance), a peer led support organisation for people who hear voices. In 1988, the Hearing Voices Network was established in England with the active support of Romme. Since then, networks have been established in 35 countries.

INTERVOICE (The International Network for Training, Education and Research into Hearing Voices) is the organisation that provides coordination and support to the Hearing Voices Movement. It is supported by people who hear voices, relatives, friends and mental health professionals including therapists, social workers, nurses, psychiatrists and psychologists.

INTERVOICE was formed in 1997, at a meeting of voice hearers, family members and mental health workers was held in Maastricht, Netherlands to consider how to organise internationally further research and work about the subject of voice hearing. The meeting decided to create a formal organisational structure to provide administrative and coordinating support to the wide variety of initiatives in the different involved countries.

The organisation is structured as a network and was incorporated in 2007 as a non-profit company and charity under UK law. It operates under the name of International Hearing Voices Projects Ltd. The president is Marius Romme and the governing body is made up of people who hear voices and mental health practitioners.

Activities

Hearing Voices Groups

Hearing Voices Groups are based on an ethos of self-help, mutual respect and empathy. They provide a safe space for people to share their experiences and to support one another. They are peer support groups, involving social support and belonging, not necessarily therapy or treatment. Groups offer an opportunity for people to accept and live with their experiences in a way that helps them regain some power over their lives. There are hundreds of hearing voices groups and networks across the world. In 2014 there were more than 180 groups in the UK. These include groups for young people, people in prison, women and people from Black and Minority Ethnic communities.

World Hearing Voices Congress

INTERVOICE hosts the annual World Hearing Voices Congress. In 2015 the 7th Congress was held in Madrid, Spain, the 2016 Congress will be held in Paris, France. Previous conferences have been held in Maastricht, Netherlands, (2009); Nottingham, England (2010), Savona, Italy (2011), Cardiff, Wales (2012); Melbourne, Australia (2013); Thessaloniki, Greece (2014); Madrid, Spain (2015).

Annual World Hearing Voices Day

This is held on 14 September and celebrates hearing voices as part of the diversity of human experience, It seeks to increase awareness of the fact that you can hear voices and be healthy. It also challenges the negative attitudes towards people who hear voices and the assumption that hearing voices, in itself, is a sign of mental illness.

Website and Social Media Platforms

INTERVOICE maintains several forums on Twitter, Facebook and other social media platforms.

Research Committee

INTERVOICE has an international research committee, that commissions research, encourages and supports exchanges and visits between member countries, the translation and publication of books and other literature on the subject of hearing voices and other related extraordinary experiences.

Impact

Appearances in Media

  • Hearing Voices, Horizon Documentary, BBC, UK (1995).
  • Angels and Demons directed by Sonya Pemberton, f2003; produced by ABC Commercial, in Enough Rope, Episode 162.
  • The Doctor Who Hears Voices, Channel 4, UK.
  • The voices in my head TED2013, Filmed February 2013.

Hearing Voices Network Cymru (Wales) maintains a media archive of articles and news items about hearing voices for the last seven years.

A study investigating media reports of the experience of hearing voices found that 84% of the articles in the study contained no suggestion that voice-hearing can be ‘normal’. Half of those that did, put voice-hearing in a religious or spiritual context, for example considering the case of Joan of Arc. Most of the articles (81.8%) connected voice-hearing to mental illness. In some cases, auditory verbal hallucinations were simply equated with insanity.

Criticism of the Hearing Voices Movement

The Hearing Voices Movement has been criticised for its stance on medication and schizophrenia and for promoting non-medical and non-evidence-based approaches to severe mental illnesses in articles by Susan Inman from the Huffington Post, such as “People Who Hear Voices Need Science-Based Advice” in 2013, and “What You’re not Hearing About the Hearing Voices Movement” in 2015.

Specific criticisms of the hearing voices approach include:

  • Using ideas that do not support science-based ways of understanding illness.
  • Undermines people’s trust in medical help that might be crucial to their wellbeing.
  • Encourages people to focus on their voices when they may be having a hard time differentiating between what is real and what is not real.
  • Does not recognise the very different needs of people with severe mental illnesses.
  • By failing to differentiate between the needs of people who actually have psychotic disorders and those who do not, HVM poses serious risks.
  • Poses real danger for the substantial number of people who lack insight into their psychotic disorder.
  • People struggling with psychotic symptoms should not be advised to emphasize the meaning of auditory hallucinations.

What is the Scale for the Assessment of Positive Symptoms?

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Introduction

Within psychological testing, the Scale for the Assessment of Positive Symptoms (SAPS) is a rating scale to measure positive symptoms in schizophrenia.

The scale was developed by Nancy Andreasen and was first published in 1984. SAPS is split into 4 domains, and within each domain separate symptoms are rated from 0 (absent) to 5 (severe). The scale is closely linked to the Scale for the Assessment of Negative Symptoms (SANS) which was published a few years earlier.

Items

  • Hallucinations:
    • Auditory Hallucinations.
    • Voices Commenting.
    • Voices Conversing.
    • Somatic or Tactile Hallucinations.
    • Olfactory Hallucinations.
    • Visual Hallucinations.
    • Global Rating of Severity of Hallucinations.
  • Delusions:
    • Persecutory Delusions.
    • Delusions of Jealousy.
    • Delusions of Sin or Guilt.
    • Grandiose Delusions.
    • Religious Delusions.
    • Somatic Delusions.
    • Ideas and Delusions of Reference.
    • Delusions of Being Controlled.
    • Delusions of Mind Reading.
    • Thought Broadcasting.
    • Thought Insertion.
    • Thought Withdrawal.
    • Global Rating of Severity of Delusions.
  • Bizarre Behaviour:
    • Clothing and Appearance.
    • Social and Sexual Behaviour.
    • Aggressive and Agitated Behaviour.
    • Repetitive or Stereotyped Behaviour.
    • Global Rating of Severity of Bizarre Behaviour.
  • Positive Formal Thought Disorder:
    • Derailment (loose associations).
    • Tangentiality.
    • Incoherence (Word salad, Schizophasia).
    • Illogicality.
    • Circumstantiality.
    • Pressure of speech.
    • Distractible speech.
    • Clanging.
    • Global Rating of Positive Formal Thought Disorder.

What is Hallucinogen Persisting Perception Disorder?

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Introduction

Hallucinogen persisting perception disorder (HPPD) is a chronic and non-psychotic disorder in which a person experiences apparent lasting or persistent visual hallucinations or perceptual distortions after a previous hallucinogenic drug experience, usually lacking the same feelings of intoxication or mental alteration experienced while on the drug.

The hallucinations and perceptual changes themselves are usually not intense or impairing and consist of visual snow, trails and after images (palinopsia), light fractals on flat surfaces, intensified colours or other psychedelic visuals. People who have never previously taken drugs have also reported some visual anomalies associated with HPPD (such as floaters and visual snow).

To be diagnosed, the disorder must cause distress or impairment in work or everyday life. Symptoms often get worse when focused on.

Brief History

In 1898, the English writer and intellectual Havelock Ellis reported a heightened sensitivity to “the more delicate phenomena of light and shade and colour” for a prolonged period of time after consuming the psychedelic drug mescaline. This may have been one of the first recorded cases of what would later be called “HPPD”. However, mild residual effects or “afterglows” from these types of drugs are not necessarily unusual nor indicative of what can be classified as a disorder like HPPD since distress to the individual is usually a requirement for diagnosis.

HPPD Subtypes

According to a 2016 review, there are two theorized subtypes of the condition. Type 1 HPPD is where people experience random, brief flashbacks. Type 2 HPPD entails experiencing persistent changes to vision, which may vary in intensity. This model has faced scrutiny however due to “flashbacks” often being considered a separate affliction and not always a perceptual one.

Cause

HPPD is not related to psychosis due to the fact those affected by the disorder can easily distinguish their visual disturbances from reality. The only certain cause of HPPD is prior use of hallucinogens. Some evidence points to phenethylamines carrying a slightly greater risk than lysergamides or tryptamines. There are no known risk factors, and what might trigger any specific disturbing hallucination is not known. Some sort of disinhibition of visual processing may be involved. It has been suggested MDMA (ecstasy) use with other drugs is linked to the development of HPPD.

Diagnosis

HPPD is a DSM-5 diagnosis with diagnostic code 292.89 (F16.983). For the diagnosis to be made, other psychological, psychiatric, or neurological conditions must be ruled out and it must cause distress in everyday life.

Treatment

As of September 2021 there is still no good evidence of any specific medicinal treatment as being commonly effective for HPPD.

Avoiding any additional use of psychoactive drugs (including cannabis and alcohol) from an early stage of the disorder seems to be an effective way for many sufferers to achieve recovery, as these substances apparently worsen the condition over time.

Some prescription drugs (lamotrigine, clonazepam, levetiracetam and others) have been known to relieve symptoms for some, but worsen symptoms or create dependencies for others.

Antipsychotic drugs and SSRIs have also been reported to help some people temporarily but worsen symptoms for others.

Some sufferers have reported benefits from prolonged water fasting, medications like acetylcysteine and lithium, and from supplements like tyrosine, ashwagandha and lion’s mane, although some users report lion’s mane and ashwagandha as having potentially negative effects or creating dependencies.

Sunglasses and talk therapy might also help those who are dealing with HPPD, but in general it seems that maintaining sobriety from all psychoactive substances is still the best solution available for this condition.

Prevalence

The prevalence of HPPD was unknown as of 2021. Estimates in the 1960s and 1970s were around 1 in 20 for intermittent HPPD among regular users of hallucinogens. In a 2010 study of psychedelic users, 23.9% reported constant HPPD-like effects, however only 4.2% considered seeking treatment due to the severity. It is not clear how common chronic HPPD may be, but one estimate in the 1990s was that 1 in 50,000 regular users might have chronic hallucinations.

Society and Culture

In the second episode of the first season of the 2014 series True Detective (“Seeing Things”), primary character Rustin Cohle (Matthew McConaughey) is depicted as having symptoms similar to HPPD such as light tracers as a result of “neurological damage” from substance use.

American journalist Andrew Callaghan, former host of the internet series All Gas No Brakes, revealed during a 2021 interview with Vice News that he has a HPPD diagnosis as a result of excessive psilocybin use at a young age. Describing his symptoms, he noted that he experiences persistent visual snow and palinopsia.

What was the Rosenham Experiment?

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Introduction

The Rosenhan experiment or Thud experiment was an experiment conducted to determine the validity of psychiatric diagnosis. The participants feigned hallucinations to enter psychiatric hospitals but acted normally afterwards. They were diagnosed with psychiatric disorders and were given antipsychotic medication. The study was conducted by psychologist David Rosenhan, a Stanford University professor, and published by the journal Science in 1973 under the title “On Being Sane in Insane Places”. It is considered an important and influential criticism of psychiatric diagnosis, and broached the topic of wrongful involuntary commitment.

Rosenhan’s study was done in two parts. The first part involved the use of healthy associates or “pseudopatients” (three women and five men, including Rosenhan himself) who briefly feigned auditory hallucinations in an attempt to gain admission to 12 psychiatric hospitals in five states in the United States. All were admitted and diagnosed with psychiatric disorders. After admission, the pseudopatients acted normally and told staff that they no longer experienced any additional hallucinations. As a condition of their release, all the patients were forced to admit to having a mental illness and had to agree to take antipsychotic medication. The average time that the patients spent in the hospital was 19 days. All but one were diagnosed with schizophrenia “in remission” before their release.

The second part of his study involved a hospital administration challenging Rosenhan to send pseudopatients to its facility, whose staff asserted that they would be able to detect the pseudopatients. Rosenhan agreed, and in the following weeks 41 out of 193 new patients were identified as potential pseudopatients, with 19 of these receiving suspicion from at least one psychiatrist and one other staff member. Rosenhan sent no pseudopatients to the hospital.

While listening to a lecture by R.D. Laing, who was associated with the anti-psychiatry movement, Rosenhan conceived of the experiment as a way to test the reliability of psychiatric diagnoses. The study concluded “it is clear that we cannot distinguish the sane from the insane in psychiatric hospitals” and also illustrated the dangers of dehumanisation and labelling in psychiatric institutions. It suggested that the use of community mental health facilities which concentrated on specific problems and behaviours rather than psychiatric labels might be a solution, and recommended education to make psychiatric workers more aware of the social psychology of their facilities.

Pseudopatient Experiment

Rosenhan himself and seven mentally healthy associates, called “pseudopatients”, attempted to gain admission to psychiatric hospitals by calling for an appointment and feigning auditory hallucinations. The hospital staff were not informed of the experiment. The pseudopatients included a psychology graduate student in his twenties, three psychologists, a pediatrician, a psychiatrist, a painter, and a housewife. None had a history of mental illness. Pseudopatients used pseudonyms, and those who worked in the mental health field were given false jobs in a different sector to avoid invoking any special treatment or scrutiny. Apart from giving false names and employment details, further biographical details were truthfully reported.

During their initial psychiatric assessment, the pseudopatients claimed to be hearing voices of the same sex as the patient which were often unclear, but which seemed to pronounce the words “empty”, “hollow”, or “thud”, and nothing else. These words were chosen as they vaguely suggest some sort of existential crisis and for the lack of any published literature referencing them as psychotic symptoms. No other psychiatric symptoms were claimed. If admitted, the pseudopatients were instructed to “act normally”, reporting that they felt fine and no longer heard voices. Hospital records obtained after the experiment indicate that all pseudopatients were characterized as friendly and cooperative by staff.

All were admitted, to 12 psychiatric hospitals across the United States, including rundown and underfunded public hospitals in rural areas, urban university-run hospitals with excellent reputations, and one expensive private hospital. Though presented with identical symptoms, seven were diagnosed with schizophrenia at public hospitals, and one with manic-depressive psychosis, a more optimistic diagnosis with better clinical outcomes, at the private hospital. Their stays ranged from 7 to 52 days, and the average was 19 days. All but one were discharged with a diagnosis of schizophrenia “in remission”, which Rosenhan considered as evidence that mental illness is perceived as an irreversible condition creating a lifelong stigma rather than a curable illness.

Despite constantly and openly taking extensive notes on the behaviour of the staff and other patients, none of the pseudopatients were identified as impostors by the hospital staff, although many of the other psychiatric patients seemed to be able to correctly identify them as impostors. In the first three hospitalisations, 35 of the total of 118 patients expressed a suspicion that the pseudopatients were sane, with some suggesting that the patients were researchers or journalists investigating the hospital. Hospital notes indicated that staff interpreted much of the pseudopatients’ behaviour in terms of mental illness. For example, one nurse labelled the note-taking of one pseudopatient as “writing behaviour” and considered it pathological. The patients’ normal biographies were recast in hospital records along the lines of what was expected of schizophrenics by the then-dominant theories of its cause.

The experiment required the pseudopatients to get out of the hospital on their own by getting the hospital to release them, though a lawyer was retained to be on call for emergencies when it became clear that the pseudopatients would not ever be voluntarily released on short notice. Once admitted and diagnosed, the pseudopatients were not able to obtain their release until they agreed with the psychiatrists that they were mentally ill and began taking antipsychotic medications, which they flushed down the toilet. No staff member reported that the pseudopatients were flushing their medication down the toilets.

Rosenhan and the other pseudopatients reported an overwhelming sense of dehumanisation, severe invasion of privacy, and boredom while hospitalised. Their possessions were searched randomly, and they were sometimes observed while using the toilet. They reported that though the staff seemed to be well-meaning, they generally objectified and dehumanised the patients, often discussing patients at length in their presence as though they were not there, and avoiding direct interaction with patients except as strictly necessary to perform official duties. Some attendants were prone to verbal and physical abuse of patients when other staff were not present. A group of patients waiting outside the cafeteria half an hour before lunchtime were said by a doctor to his students to be experiencing “oral-acquisitive” psychiatric symptoms. Contact with doctors averaged 6.8 minutes per day.

Non-Existent Impostor Experiment

For this experiment, Rosenhan used a well-known research and teaching hospital, whose staff had heard of the results of the initial study but claimed that similar errors could not be made at their institution. Rosenhan arranged with them that during a three-month period, one or more pseudopatients would attempt to gain admission and the staff would rate every incoming patient as to the likelihood they were an impostor. Out of 193 patients, 41 were considered to be impostors and a further 42 were considered suspect. In reality, Rosenhan had sent no pseudopatients; all patients suspected as impostors by the hospital staff were ordinary patients. This led to a conclusion that “any diagnostic process that lends itself too readily to massive errors of this sort cannot be a very reliable one.”

Impact

Rosenhan published his findings in Science, in which he criticised the reliability of psychiatric diagnosis and the disempowering and demeaning nature of patient care experienced by the associates in the study. In addition, he described his work in a variety of news appearances, including to the BBC:

I told friends, I told my family: “I can get out when I can get out. That’s all. I’ll be there for a couple of days and I’ll get out.” Nobody knew I’d be there for two months … The only way out was to point out that they’re [the psychiatrists are] correct. They had said I was insane, “I am insane; but I am getting better.” That was an affirmation of their view of me.

The experiment is argued to have “accelerated the movement to reform mental institutions and to deinstitutionalize as many mental patients as possible”.

Many respondents to the publication defended psychiatry, arguing that as psychiatric diagnosis relies largely on the patient’s report of their experiences, faking their presence no more demonstrates problems with psychiatric diagnosis than lying about other medical symptoms. In this vein, psychiatrist Robert Spitzer quoted Seymour S. Kety in a 1975 criticism of Rosenhan’s study:

If I were to drink a quart of blood and, concealing what I had done, come to the emergency room of any hospital vomiting blood, the behavior of the staff would be quite predictable. If they labeled and treated me as having a bleeding peptic ulcer, I doubt that I could argue convincingly that medical science does not know how to diagnose that condition.

Kety also argued that psychiatrists should not necessarily be expected to assume that a patient is pretending to have mental illness, thus the study lacked realism. Rosenhan called this the “experimenter effect” or “expectation bias”, something indicative of the problems he uncovered rather than a problem in his methodology.

In The Great Pretender, a 2019 book on Rosenhan, author Susannah Cahalan questions the veracity and validity of the Rosenhan experiment. Examining documents left behind by Rosenhan after his death, Cahalan finds apparent distortion in the Science article: inconsistent data, misleading descriptions, and inaccurate or fabricated quotations from psychiatric records. Moreover, despite an extensive search, she is only able to identify two of the eight pseudopatients: Rosenhan himself, and a graduate student whose testimony is allegedly inconsistent with Rosenhan’s description in the article. In light of Rosenhan’s seeming willingness to bend the truth in other ways regarding the experiment, Cahalan questions whether some or all of the six other pseudopatients might have been simply invented by Rosenhan.

Related Experiments

In 1887 American investigative journalist Nellie Bly feigned symptoms of mental illness to gain admission to a lunatic asylum and report on the terrible conditions therein. The results were published as Ten Days in a Mad-House.]

In 1968 Maurice K. Temerlin split 25 psychiatrists into two groups and had them listen to an actor portraying a character of normal mental health. One group was told that the actor “was a very interesting man because he looked neurotic, but actually was quite psychotic” while the other was told nothing. Sixty percent of the former group diagnosed psychoses, most often schizophrenia, while none of the control group did so.

In 1988, Loring and Powell gave 290 psychiatrists a transcript of a patient interview and told half of them that the patient was black and the other half white; they concluded of the results that “clinicians appear to ascribe violence, suspiciousness, and dangerousness to black clients even though the case studies are the same as the case studies for the white clients.”

In 2004, psychologist Lauren Slater claimed to have conducted an experiment very similar to Rosenhan’s for her book Opening Skinner’s Box. Slater wrote that she had presented herself at 9 psychiatric emergency rooms with auditory hallucinations, resulting in being diagnosed “almost every time” with psychotic depression. However, when challenged to provide evidence of actually conducting her experiment, she could not. The serious methodologic and other concerns regarding Slater’s work appeared as a series of responses to a journal report, in the same journal.

In 2008, the BBC’s Horizon science programme performed a similar experiment over two episodes entitled “How Mad Are You?”. The experiment involved ten subjects, five with previously diagnosed mental health conditions, and five with no such diagnosis. They were observed by three experts in mental health diagnoses and their challenge was to identify the five with mental health problems solely from their behaviour, without speaking to the subjects or learning anything of their histories. The experts correctly diagnosed two of the ten patients, misdiagnosed one patient, and incorrectly identified two healthy patients as having mental health problems. Unlike the other experiments listed here, however, the aim of this journalistic exercise was not to criticise the diagnostic process, but to minimise the stigmatisation of the mentally ill. It aimed to illustrate that people with a previous diagnosis of a mental illness could live normal lives with their health problems not obvious to observers from their behaviour.

What are Hallucinations in Psychosis?

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Introduction

Visual hallucinations in psychosis are hallucinations accompanied by delusions, which are abnormal beliefs that are endorsed by patients as real, that persist in spite of evidence to the contrary, and that are not part of a patient’s culture or subculture.

Presentation

Visual hallucinations in psychoses are reported to have physical properties similar to real perceptions. They are often life-sized, detailed, and solid, and are projected into the external world. They typically appear anchored in external space, just beyond the reach of individuals, or further away. They can have three-dimensional shapes, with depth and shadows, and distinct edges. They can be colourful or in black and white and can be static or have movement.

Simple versus Complex

Visual hallucinations may be simple, or non-formed visual hallucinations, or complex, or formed visual hallucinations.

Simple visual hallucinations are also referred to as non-formed or elementary visual hallucinations. They can take the form of multicoloured lights, colours, geometric shapes, indiscrete objects. Simple visual hallucinations without structure are known as phosphenes and those with geometric structure are known as photopsias. These hallucinations are caused by irritation to the primary visual cortex (Brodmann’s area 17).

Complex visual hallucinations are also referred to as formed visual hallucinations. They tend to be clear, lifelike images or scenes, such as faces of animals or people. Sometimes, hallucinations are ‘Lilliputian’, i.e. patients experience visual hallucinations where there are miniature people, often undertaking unusual actions. Lilliputian hallucinations may be accompanied by wonder, rather than terror.

Content

The frequency of hallucinations varies widely from rare to frequent, as does duration (seconds to minutes). The content of hallucinations varies as well. Complex (formed) visual hallucinations are more common than Simple (non-formed) visual hallucinations. In contrast to hallucinations experienced in organic conditions, hallucinations experienced as symptoms of psychoses tend to be more frightening. An example of this would be hallucinations that have imagery of bugs, dogs, snakes, distorted faces. Visual hallucinations may also be present in those with Parkinson’s, where visions of dead individuals can be present. In psychoses, this is relatively rare, although visions of God, angels, the devil, saints, and fairies are common. Individuals often report being surprised when hallucinations occur and are generally helpless to change or stop them. In general, individuals believe that visions are experienced only by themselves.

Causes

Two neurotransmitters are particularly important in visual hallucinations – serotonin and acetylcholine. They are concentrated in the visual thalamic nuclei and visual cortex.

The similarity of visual hallucinations that stem from diverse conditions suggest a common pathway for visual hallucinations. Three pathophysiologic mechanisms are thought to explain this.

The first mechanism has to do with cortical centres responsible for visual processing. Irritation of visual association cortices (Brodmann’s areas 18 and 19) cause complex visual hallucinations.

The second mechanism is deafferentation, the interruption or destruction of the afferent connections of nerve cells, of the visual system, caused by lesions, leading to the removal of normal inhibitory processes on cortical input to visual association areas, leading to complex hallucinations as a release phenomenon.

The third mechanism has to do with the reticular activating system, which plays a role in the maintenance of arousal. Lesions in the brain stem can cause visual hallucinations. Visual hallucinations are frequent in those with certain sleep disorders, occurring more often when drowsy. This suggests that the reticular activating system plays a part in visual hallucinations, although the precise mechanism has still not fully been established.

Prevalence

Hallucinations in those with psychoses are often experienced in colour, and most often are multi-modal, consisting of visual and auditory components. They frequently accompany paranoia or other thought disorders, and tend to occur during the daytime and are associated with episodes of excess excitability. The DSM-V lists visual hallucinations as a primary diagnostic criterion for several psychotic disorders, including schizophrenia and schizoaffective disorder.

The lifetime prevalence of all psychotic disorders is 3.48% and that of the different diagnostic groups are as follows:

  • 0.87% for schizophrenia.
  • 0.32% for schizoaffective disorder.
  • 0.07% for schizophreniform disorder.
  • 0.18% for delusional disorder.
  • 0.24% for bipolar I disorder.
  • 0.35% for major depressive disorder with psychotic features.
  • 0.42% for substance-induced psychotic disorders.
  • 0.21% for psychotic disorders due to a general medical condition.

Visual hallucinations can occur as a symptom of the above psychotic disorders in 24% to 72% of patients at some point in the course of their illness. Not all individuals who experience hallucinations have a psychotic disorder. Many physical and psychiatric disorders can manifest with hallucinations, and some individuals may have more than one disorder that could cause different types of hallucinations.

What is Hallucination?

Published on by Andrew Marshall17 Comments

Introduction

A hallucination is a perception in the absence of external stimulus that has qualities of real perceptions.

Hallucinations are vivid, substantial, and are perceived to be located in external objective space. They are distinguishable from several related phenomena, such as dreaming, which does not involve wakefulness; pseudohallucination, which does not mimic real perception, and is accurately perceived as unreal; illusion, which involves distorted or misinterpreted real perception; and imagery (imagination), which does not mimic real perception, and is under voluntary control. Hallucinations also differ from “delusional perceptions”, in which a correctly sensed and interpreted stimulus (i.e. a real perception) is given some additional (and typically absurd) significance.

Hallucinations can occur in any sensory modality – visual, auditory, olfactory, gustatory, tactile, proprioceptive, equilibrioceptive, nociceptive, thermoceptive and chronoceptive.

A mild form of hallucination is known as a disturbance, and can occur in most of the senses above. These may be things like seeing movement in peripheral vision, or hearing faint noises or voices. Auditory hallucinations are very common in schizophrenia. They may be benevolent (telling the subject good things about themselves) or malicious, cursing the subject, etc. 55% of auditory hallucinations are malicious in content, for example, people talking about the subject behind their back, etc. Like auditory hallucinations, the source of the visual counterpart can also be behind the subject’s back. This can produce a feeling of being looked or stared at, usually with malicious intent. Frequently, auditory hallucinations and their visual counterpart are experienced by the subject together.

Hypnagogic hallucinations and hypnopompic hallucinations are considered normal phenomena. Hypnagogic hallucinations can occur as one is falling asleep and hypnopompic hallucinations occur when one is waking up. Hallucinations can be associated with drug use (particularly deliriants), sleep deprivation, psychosis, neurological disorders, and delirium tremens.

The word “hallucination” itself was introduced into the English language by the 17th-century physician Sir Thomas Browne in 1646 from the derivation of the Latin word alucinari meaning to wander in the mind. For Browne, hallucination means a sort of vision that is “depraved and receive[s] its objects erroneously”.

Classification

Hallucinations may be manifested in a variety of forms. Various forms of hallucinations affect different senses, sometimes occurring simultaneously, creating multiple sensory hallucinations for those experiencing them.

Visual

A visual hallucination is “the perception of an external visual stimulus where none exists”. A separate but related phenomenon is a visual illusion, which is a distortion of a real external stimulus. Visual hallucinations are classified as simple or complex:

  • Simple visual hallucinations (SVH) are also referred to as non-formed visual hallucinations and elementary visual hallucinations.
    • These terms refer to lights, colours, geometric shapes, and indiscrete objects.
    • These can be further subdivided into phosphenes which are SVH without structure, and photopsias which are SVH with geometric structures.
  • Complex visual hallucinations (CVH) are also referred to as formed visual hallucinations.
    • CVHs are clear, lifelike images or scenes such as people, animals, objects, places, etc.

For example, one may report hallucinating a giraffe. A simple visual hallucination is an amorphous figure that may have a similar shape or colour to a giraffe (looks like a giraffe), while a complex visual hallucination is a discrete, lifelike image that is, unmistakably, a giraffe.

Auditory

Auditory hallucinations (also known as paracusia) are the perception of sound without outside stimulus. These hallucinations are the most common type of hallucination. Auditory hallucinations can be divided into two categories: elementary and complex. Elementary hallucinations are the perception of sounds such as hissing, whistling, an extended tone, and more. In many cases, tinnitus is an elementary auditory hallucination. However, some people who experience certain types of tinnitus, especially pulsatile tinnitus, are actually hearing the blood rushing through vessels near the ear. Because the auditory stimulus is present in this situation, it does not qualify it as a hallucination.

Complex hallucinations are those of voices, music, or other sounds that may or may not be clear, may or may not be familiar, and may be friendly, aggressive, or among other possibilities. A hallucination of a single individual person of one or more talking voices is particularly associated with psychotic disorders such as schizophrenia, and hold special significance in diagnosing these conditions.

Another typical disorder where auditory hallucinations are very common is dissociative identity disorder. In schizophrenia voices are normally perceived coming from outside the person but in dissociative disorders they are perceived as originating from within the person, commenting in their head instead of behind their back. Differential diagnosis between schizophrenia and dissociative disorders is challenging due to many overlapping symptoms, especially Schneiderian first rank symptoms such as hallucinations. However, many people not suffering from diagnosable mental illness may sometimes hear voices as well. One important example to consider when forming a differential diagnosis for a patient with paracusia is lateral temporal lobe epilepsy. Despite the tendency to associate hearing voices, or otherwise hallucinating, and psychosis with schizophrenia or other psychiatric illnesses, it is crucial to take into consideration that, even if a person does exhibit psychotic features, he/she does not necessarily suffer from a psychiatric disorder on its own. Disorders such as Wilson’s disease, various endocrine diseases, numerous metabolic disturbances, multiple sclerosis, systemic lupus erythematosus, porphyria, sarcoidosis, and many others can present with psychosis.

Musical hallucinations are also relatively common in terms of complex auditory hallucinations and may be the result of a wide range of causes ranging from hearing-loss (such as in musical ear syndrome, the auditory version of Charles Bonnet syndrome), lateral temporal lobe epilepsy, arteriovenous malformation, stroke, lesion, abscess, or tumour.

The Hearing Voices Movement is a support and advocacy group for people who hallucinate voices, but do not otherwise show signs of mental illness or impairment.

High caffeine consumption has been linked to an increase in likelihood of one experiencing auditory hallucinations. A study conducted by the La Trobe University School of Psychological Sciences revealed that as few as five cups of coffee a day (approximately 500 mg of caffeine) could trigger the phenomenon.

Command

Command hallucinations are hallucinations in the form of commands; they can be auditory or inside of the person’s mind or consciousness. The contents of the hallucinations can range from the innocuous to commands to cause harm to the self or others. Command hallucinations are often associated with schizophrenia. People experiencing command hallucinations may or may not comply with the hallucinated commands, depending on the circumstances. Compliance is more common for non-violent commands.

Command hallucinations are sometimes used to defend a crime that has been committed, often homicides. In essence, it is a voice that one hears and it tells the listener what to do. Sometimes the commands are quite benign directives such as “Stand up” or “Shut the door.” Whether it is a command for something simple or something that is a threat, it is still considered a “command hallucination.” Some helpful questions that can assist one in figuring out if they may be suffering from this includes: “What are the voices telling you to do?”, “When did your voices first start telling you to do things?”, “Do you recognize the person who is telling you to harm yourself (or others)?”, “Do you think you can resist doing what the voices are telling you to do?”

Olfactory

Phantosmia (olfactory hallucinations), smelling an odour that is not actually there, and parosmia (olfactory illusions), inhaling a real odour but perceiving it as different scent than remembered, are distortions to the sense of smell (olfactory system), and in most cases, are not caused by anything serious and will usually go away on their own in time. It can result from a range of conditions such as nasal infections, nasal polyps, dental problems, migraines, head injuries, seizures, strokes, or brain tumours. Environmental exposures can sometimes cause it as well, such as smoking, exposure to certain types of chemicals (e.g. insecticides or solvents), or radiation treatment for head or neck cancer. It can also be a symptom of certain mental disorders such as depression, bipolar disorder, intoxication or withdrawal from drugs and alcohol, or psychotic disorders (e.g. schizophrenia). The perceived odours are usually unpleasant and commonly described as smelling burned, foul spoiled, or rotten.

Tactile

Tactile hallucinations are the illusion of tactile sensory input, simulating various types of pressure to the skin or other organs. One subtype of tactile hallucination, formication, is the sensation of insects crawling underneath the skin and is frequently associated with prolonged cocaine use. However, formication may also be the result of normal hormonal changes such as menopause, or disorders such as peripheral neuropathy, high fevers, Lyme disease, skin cancer, and more.

Gustatory

This type of hallucination is the perception of taste without a stimulus. These hallucinations, which are typically strange or unpleasant, are relatively common among individuals who have certain types of focal epilepsy, especially temporal lobe epilepsy. The regions of the brain responsible for gustatory hallucination in this case are the insula and the superior bank of the sylvian fissure.

General Somatic Sensations

General somatic sensations of a hallucinatory nature are experienced when an individual feels that their body is being mutilated, i.e. twisted, torn, or disembowelled. Other reported cases are invasion by animals in the person’s internal organs, such as snakes in the stomach or frogs in the rectum. The general feeling that one’s flesh is decomposing is also classified under this type of hallucination.

Cause

Hallucinations can be caused by a number of factors.

Hypnagogic Hallucination

These hallucinations occur just before falling asleep and affect a high proportion of the population: in one survey 37% of the respondents experienced them twice a week. The hallucinations can last from seconds to minutes; all the while, the subject usually remains aware of the true nature of the images. These may be associated with narcolepsy. Hypnagogic hallucinations are sometimes associated with brainstem abnormalities, but this is rare.

Peduncular Hallucinosis

Peduncular means pertaining to the peduncle, which is a neural tract running to and from the pons on the brain stem. These hallucinations usually occur in the evenings, but not during drowsiness, as in the case of hypnagogic hallucination. The subject is usually fully conscious and then can interact with the hallucinatory characters for extended periods of time. As in the case of hypnagogic hallucinations, insight into the nature of the images remains intact. The false images can occur in any part of the visual field, and are rarely polymodal.

Delirium Tremens

One of the more enigmatic forms of visual hallucination is the highly variable, possibly polymodal delirium tremens. Individuals suffering from delirium tremens may be agitated and confused, especially in the later stages of this disease. Insight is gradually reduced with the progression of this disorder. Sleep is disturbed and occurs for a shorter period of time, with rapid eye movement sleep.

Parkinson’s Disease and Lewy Body Dementia

Parkinson’s disease is linked with Lewy body dementia for their similar hallucinatory symptoms. The symptoms strike during the evening in any part of the visual field, and are rarely polymodal. The segue into hallucination may begin with illusions where sensory perception is greatly distorted, but no novel sensory information is present. These typically last for several minutes, during which time the subject may be either conscious and normal or drowsy/inaccessible. Insight into these hallucinations is usually preserved and REM sleep is usually reduced. Parkinson’s disease is usually associated with a degraded substantia nigra pars compacta, but recent evidence suggests that PD affects a number of sites in the brain. Some places of noted degradation include the median raphe nuclei, the noradrenergic parts of the locus coeruleus, and the cholinergic neurons in the parabrachial area and pedunculopontine nuclei of the tegmentum.

Migraine Coma

This type of hallucination is usually experienced during the recovery from a comatose state. The migraine coma can last for up to two days, and a state of depression is sometimes comorbid. The hallucinations occur during states of full consciousness, and insight into the hallucinatory nature of the images is preserved. It has been noted that ataxic lesions accompany the migraine coma.

Charles Bonnet Syndrome

Charles Bonnet syndrome is the name given to visual hallucinations experienced by a partially or severely sight impaired person. The hallucinations can occur at any time and can distress people of any age, as they may not initially be aware that they are hallucinating. They may fear for their own mental health initially, which may delay them sharing with carers until they start to understand it themselves. The hallucinations can frighten and disconcert as to what is real and what is not. The hallucinations can sometimes be dispersed by eye movements, or by reasoned logic such as, “I can see fire but there is no smoke and there is no heat from it” or perhaps, “We have an infestation of rats but they have pink ribbons with a bell tied on their necks.” Over elapsed months and years, the manifestation of the hallucinations may change, becoming more or less frequent with changes in ability to see. The length of time that the sight impaired person can suffer from these hallucinations varies according to the underlying speed of eye deterioration. A differential diagnosis are ophthalmopathic hallucinations.

Focal Epilepsy

Visual hallucinations due to focal seizures differ depending on the region of the brain where the seizure occurs. For example, visual hallucinations during occipital lobe seizures are typically visions of brightly coloured, geometric shapes that may move across the visual field, multiply, or form concentric rings and generally persist from a few seconds to a few minutes. They are usually unilateral and localised to one part of the visual field on the contralateral side of the seizure focus, typically the temporal field. However, unilateral visions moving horizontally across the visual field begin on the contralateral side and move toward the ipsilateral side.

Temporal lobe seizures, on the other hand, can produce complex visual hallucinations of people, scenes, animals, and more as well as distortions of visual perception. Complex hallucinations may appear to be real or unreal, may or may not be distorted with respect to size, and may seem disturbing or affable, among other variables. One rare but notable type of hallucination is heautoscopy, a hallucination of a mirror image of one’s self. These “other selves” may be perfectly still or performing complex tasks, may be an image of a younger self or the present self, and tend to be briefly present. Complex hallucinations are a relatively uncommon finding in temporal lobe epilepsy patients. Rarely, they may occur during occipital focal seizures or in parietal lobe seizures.

Distortions in visual perception during a temporal lobe seizure may include size distortion (micropsia or macropsia), distorted perception of movement (where moving objects may appear to be moving very slowly or to be perfectly still), a sense that surfaces such as ceilings and even entire horizons are moving farther away in a fashion similar to the dolly zoom effect, and other illusions. Even when consciousness is impaired, insight into the hallucination or illusion is typically preserved.

Drug-Induced Hallucination

Drug-induced hallucinations are caused by hallucinogens, dissociatives, and deliriants, including many drugs with anticholinergic actions and certain stimulants, which are known to cause visual and auditory hallucinations. Some psychedelics such as lysergic acid diethylamide (LSD) and psilocybin can cause hallucinations that range in the spectrum of mild to intense.

Hallucinations, pseudohallucinations, or intensification of pareidolia, particularly auditory, are known side effects of opioids to different degrees – it may be associated with the absolute degree of agonism or antagonism of especially the kappa opioid receptor, sigma receptors, delta opioid receptor and the NMDA receptors or the overall receptor activation profile as synthetic opioids like those of the pentazocine, levorphanol, fentanyl, pethidine, methadone and some other families are more associated with this side effect than natural opioids like morphine and codeine and semi-synthetics like hydromorphone, amongst which there also appears to be a stronger correlation with the relative analgesic strength. Three opioids, Cyclazocine (a benzormorphan opioid/pentazocine relative) and two levorphanol-related morphinan opioids, Cyclorphan and Dextrorphan are classified as hallucinogens, and Dextromethorphan as a dissociative. These drugs also can induce sleep (relating to hypnagogic hallucinations) and especially the pethidines have atropine-like anticholinergic activity, which was possibly also a limiting factor in the use, the psychotomometic side effects of potentiating morphine, oxycodone, and other opioids with scopolamine (respectively in the Twilight Sleep technique and the combination drug Skophedal, which was eukodal (oxycodone), scopolamine and ephedrine, called the “wonder drug of the 1930s” after its invention in Germany in 1928, but only rarely specially compounded today) (q.q.v.).

Sensory Deprivation Hallucination

Hallucinations can be caused by sensory deprivation when it occurs for prolonged periods of time, and almost always occurs in the modality being deprived (visual for blindfolded/darkness, auditory for muffled conditions, etc).

Experimentally-Induced Hallucinations

Anomalous experiences, such as so-called benign hallucinations, may occur in a person in a state of good mental and physical health, even in the apparent absence of a transient trigger factor such as fatigue, intoxication or sensory deprivation.

The evidence for this statement has been accumulating for more than a century. Studies of benign hallucinatory experiences go back to 1886 and the early work of the Society for Psychical Research, which suggested approximately 10% of the population had experienced at least one hallucinatory episode in the course of their life. More recent studies have validated these findings; the precise incidence found varies with the nature of the episode and the criteria of “hallucination” adopted, but the basic finding is now well-supported.

Non-Celiac Gluten Sensitivity

There is tentative evidence of a relationship with non-celiac gluten sensitivity, the so-called “gluten psychosis”.

Pathophysiology

Dopaminergic and Serotoninergic Hallucinations

It has been reported that in serotoninergic hallucinations, the person maintains an awareness that they is hallucinating, unlike dopaminergic hallucinations.

Neuroanatomy

Hallucinations are associated with structural and functional abnormalities in primary and secondary sensory cortices. Reduced grey matter in regions of the superior temporal gyrus/middle temporal gyrus, including Broca’s area, is associated with auditory hallucinations as a trait, while acute hallucinations are associated with increased activity in the same regions along with the hippocampus, parahippocampus, and the right hemispheric homologue of Broca’s area in the inferior frontal gyrus. Grey and white matter abnormalities in visual regions are associated with visual hallucinations in diseases such as Alzheimer’s disease, further supporting the notion of dysfunction in sensory regions underlying hallucinations.

One proposed model of hallucinations posits that over-activity in sensory regions, which is normally attributed to internal sources via feedforward networks to the inferior frontal gyrus, is interpreted as originating externally due to abnormal connectivity or functionality of the feedforward network. This is supported by cognitive studies those with hallucinations, who have demonstrated abnormal attribution of self generated stimuli.

Disruptions in thalamocortical circuitry may underlie the observed top down and bottom up dysfunction. Thalamocortical circuits, composed of projections between thalamic and cortical neurons and adjacent interneurons, underlie certain electrophysical characteristics (gamma oscillations) that are underlie sensory processing. Cortical inputs to thalamic neurons enable attentional modulation of sensory neurons. Dysfunction in sensory afferents, and abnormal cortical input may result in pre-existing expectations modulating sensory experience, potentially resulting in the generation of hallucinations. Hallucinations are associated with less accurate sensory processing, and more intense stimuli with less interference are necessary for accurate processing and the appearance of gamma oscillations (called “gamma synchrony”). Hallucinations are also associated with the absence of reduction in P50 amplitude in response to the presentation of a second stimuli after an initial stimulus; this is thought to represent failure to gate sensory stimuli, and can be exacerbated by dopamine release agents.

Abnormal assignment of salience to stimuli may be one mechanism of hallucinations. Dysfunctional dopamine signalling may lead to abnormal top down regulation of sensory processing, allowing expectations to distort sensory input.

Treatments

There are few treatments for many types of hallucinations. However, for those hallucinations caused by mental disease, a psychologist or psychiatrist should be consulted, and treatment will be based on the observations of those doctors. Antipsychotic and atypical antipsychotic medication may also be utilised to treat the illness if the symptoms are severe and cause significant distress. For other causes of hallucinations there is no factual evidence to support any one treatment is scientifically tested and proven. However, abstaining from hallucinogenic drugs, stimulant drugs, managing stress levels, living healthily, and getting plenty of sleep can help reduce the prevalence of hallucinations. In all cases of hallucinations, medical attention should be sought out and informed of one’s specific symptoms.

Epidemiology

Several recent studies on the prevalence of hallucinations in the general population have appeared. A 2020 US study indicated a lifetime prevalence of 10-15% for vivid sensory hallucinations. Compared with the English Sidgewick Study of 1894, relative frequencies of sensory modalities differed in the US with fewer visual hallucinations.