Diagnosis of Substance Use Disorders

A diagnosis is made via a medical professional’s evaluation, and sometimes an individual’s self-report.

Sometimes a substance use disorder is diagnosed when individuals go to a medical professional/health care practitioner because they want help stopping use of a drug.

Other individuals try to hide their drug use, and medical professionals may suspect problems with drug use only when they notice changes in an individual’s mood or behaviour.

Sometimes medical professionals discover signs of substance use during a physical examination. For example, they may discover track marks caused by repeatedly injecting drugs intravenously. Track marks are lines of tiny, dark dots (needle punctures) surrounded by an area of darkened or discoloured skin. Injecting drugs under the skin causes circular scars or ulcers. Individuals may claim other reasons for the marks, such as frequent blood donations, bug bites, or other injuries.

Medical professionals/health care practitioners also use other methods (such as questionnaires) to identify a substance use disorder.

Urine and sometimes blood tests may be done to check for the presence of drugs.

Criteria for Diagnosis

The criteria for diagnosing a substance use disorder fall into four categories:

1. The person cannot control use of the substance.
2. The person’s ability to meet social obligations is compromised by use of the substance.
3. The person uses the substance in physically dangerous situations.
4. The person shows physical signs of use and/or dependence.

Inability to Control Use

• The individual:
  • Takes the substance in larger amounts or for a longer time than originally planned.
  • Desires to stop or cut down use of the substance.
  • Spends a lot of time obtaining, using, or recovering from the effects of the substance.
  • Craves the substance.

Social Impairment

• The individual:
  • Fails to fulfil major role obligations at work, school, or home.
  • Continues to use the substance even though it causes (or worsens) social or interpersonal problems.
  • Gives up or reduces important social, occupational, or recreational activity because of substance use.

Risky Use

• The individual:
  • Uses the substance in physically hazardous situations (e.g. when driving or in dangerous social circumstances).
  • Continues to use the substance despite knowing it is worsening a medical or psychological problem.

Physical Symptoms [Note 1]

• Tolerance:
  • The individual needs to use increasingly more of the substance to feel the desired effect.
• Withdrawal:
  • Unpleasant physical effects occur when the substance is stopped or when it is counteracted by another substance.

Note 1

It is important to note that some drugs, particularly opioids, sedative/hypnotics, and stimulants, can result in tolerance and/or withdrawal symptoms even when taken as prescribed for legitimate medical reasons and for relatively brief periods (less than one (1) week for opioids).

Withdrawal symptoms that develop following appropriate medical use do not warrant the diagnosis of a substance use disorder. For example, when individuals with severe pain due to advanced cancer become dependent (psychologically and physically) on an opioid such as morphine, their withdrawal symptoms are not considered evidence of a substance use disorder.

Severity of Substance Use Disorder

Individuals who have two (2) or more of the above criteria within a twelve (12) month period are considered to have a substance use disorder.

The severity of the substance use disorder is determined by the number of criteria met:

• Mild: 2 to 3 criteria.
• Moderate: 4 to 5 criteria.
• Severe: ≥ 6 criteria.