Cannabis-induced psychotic disorder

Essential (Required) Features:

• The presentation is characterized by psychotic symptoms (e.g., delusions, hallucinations, or disorganized thinking or behaviour) that develop during or soon after intoxication with or withdrawal from cannabis.
• The intensity or duration of the psychotic symptoms is substantially in excess of psychotic-like disturbances of perception, cognition, or behaviour that are characteristic of Cannabis Intoxication or Cannabis Withdrawal.
• The symptoms are not better accounted for by another mental disorder such as Schizophrenia or a Mood Disorder with psychotic symptoms. Evidence supporting a diagnosis of another mental disorder would include psychotic symptoms preceding the onset of cannabis use, the symptoms persisting for a substantial period of time after cessation of cannabis use or withdrawal (e.g., 1 month or more), or other evidence of a pre-existing mental disorder with psychotic symptoms (e.g., a history of prior episodes not associated with cannabis use).
• The symptoms are not a manifestation of another medical condition.
• The symptoms cause significant distress or significant impairment in personal, family, social, educational, occupational or other important areas of functioning.

When making a diagnosis of Cannabis-Induced Psychotic Disorder, an additional diagnosis indicating the related pattern of cannabis use should also be assigned. These include Episode of Harmful Use of Cannabis, Harmful Pattern of Use of Cannabis, and Cannabis Dependence. A diagnosis of Cannabis Intoxication or Cannabis Withdrawal may also be assigned if applicable.

Additional Clinical Features:

• Cannabis-Induced Psychotic Disorder may present with patterns of symptoms that vary according to the characteristics of the user (e.g., genetics, metabolism, personality factors). Cannabis use in higher amounts or over longer periods of time is more likely to be associated with the development of a Cannabis-Induced Psychotic Disorder.
• Symptoms of Cannabis-Induced Psychotic Disorder usually resolve or improve after sustained cessation of cannabis use.
• The duration of Substance Withdrawal for some substances can be protracted. For substances with more protracted withdrawal periods, the onset of symptoms of Substance-Induced Psychotic Disorder can occur up to several weeks after the cessation of substance use. Substance-Induced Psychotic Disorder symptoms related to substances with more protracted withdrawal periods may also last for correspondingly longer periods of time.
• In cases in which multiple psychoactive substance are used, it is often challenging to distinguish which substance is the cause of the Substance-Induced Psychotic Disorder. When the specific etiological substance cannot be determined, a diagnosis of Substance-Induced Psychotic Disorder Due to Multiple Specified Psychoactive Substances including Medications may assigned. In cases of multiple psychoactive substance use in which more than one specific substance can be identified as a cause of the Substance-Induced Psychotic Disorder, the corresponding specific Substance-Induced Psychotic Disorder diagnoses should be given instead.

Boundary with Normality (Threshold):

• Symptoms of Cannabis-Induced Psychotic Disorders should be differentiated from known side effects of medical cannabinoids that are not significantly impairing or distressing and from transient physiological aftereffects of intoxication (‘hangover effect’). The duration or severity of the symptoms in Cannabis-Induced Psychotic Disorders must be in excess of side effects or ‘hangover effects’ of Cannabis and result in significant distress or impairment of functioning.

Boundaries with Other Disorders and Conditions (Differential Diagnosis):

• Boundary with Cannabis Intoxication and Cannabis Withdrawal: Mental or behavioural symptoms that occur during Cannabis Intoxication or Cannabis Withdrawal should only be used as a basis for diagnosing a Cannabis-Induced Psychotic Disorder if the intensity or duration of the symptoms is substantially in excess of those that are characteristic of Cannabis Intoxication or Cannabis Withdrawal and the symptoms are sufficiently severe to warrant specific clinical attention.
• Boundary with Episode of Harmful Use of Cannabis, Harmful Pattern of Use of Cannabis, or Cannabis Dependence: The impact of repeated or continuous use of cannabis characteristic of Harmful Pattern of Use of Cannabis and Cannabis Dependence may include Cannabis-Induced Psychotic Disorder. Cannabis-Induced Psychotic Disorders can also be associated with a single episode of cannabis use. In such cases, a Cannabis-Induced Psychotic Disorder should be diagnosed together with a primary diagnosis of Episode of Harmful Use of Cannabis, Harmful Pattern of Use of Cannabis, or Cannabis Dependence.
• Boundary with mental disorders not induced by cannabis: Cannabis-Induced Psychotic Disorders are differentiated from mental disorders with similar features that are not induced by cannabis on the basis of their onset, course and clinical features. A diagnosis of Cannabis-Induced Psychotic Disorder requires evidence from history, physical or mental examination, or laboratory findings of recent cannabis use, intoxication or withdrawal. Most Cannabis-Induced Mental Disorders resolve or improve within several weeks of cessation of cannabis use. Mental disorders not induced by cannabis may precede the onset of cannabis use or may continue to be symptomatic during periods of sustained abstinence. The co-occurrence of cannabis use or withdrawal and onset of symptoms of mental disorders should not be taken as evidence for a presumptive diagnosis of a Cannabis-Induced Psychotic Disorder. Some people use substances to suppress symptoms of mental disorders (e.g., Schizophrenia and Other Primary Psychotic Disorders, Mood Disorders, Anxiety and Fear-Related Disorders, Personality Disorders) and full symptomatic presentations only emerge upon cessation or reduction in substance use. Furthermore, cannabis use can exacerbate symptoms or precipitate an episode of a pre-existing mental disorder. Finally, cannabis use may be associated with but not aetiologic for new onset of symptoms of a mental disorder. Although a diagnosis of a Cannabis-Induced Psychotic Disorder should not be assigned under these circumstances, an additional diagnosis of Episode of Harmful Use of Cannabis, Harmful Pattern of Use of Cannabis, or Cannabis Dependence may still be appropriate.