F12 — Mental and behavioural disorders due to use of cannabinoids

What is this category?

F12 applies the block's shared framework to cannabinoids, but its highest-yield teaching points are acute intoxication (perceptual and anxiety phenomena that can look alarming but are self-limiting) and psychotic disorder (F12.5) — specifically, distinguishing a transient intoxication-related perceptual disturbance from a genuine substance-induced psychotic disorder, and both of those from an independent psychotic illness.

Core diagnostic concept

For F12, the central classification question is often not about dependence at all but about timing and persistence of psychotic-quality phenomena: did unusual perceptions or beliefs occur only during intoxication and resolve as the drug wore off (intoxication), do they persist as a more sustained psychotic picture temporally linked to use (F12.5), or do they continue well beyond what cannabis alone would explain, raising the question of an independent psychotic illness that cannabis use may have precipitated or coincided with?

Key diagnostic features

Acute intoxication phenomena

Perceptual alterations, anxiety, suspiciousness, or transient paranoid ideation occurring during intoxication, typically resolving within hours as the drug's effects wear off.

Dependence syndrome

The same six-criteria cluster — desire/compulsion, control difficulty, tolerance, a withdrawal state, neglect of alternatives, continued use despite harm — applied to cannabis; historically debated but now well recognised as a genuine, if often milder, dependence syndrome.

Withdrawal state

Irritability, sleep disturbance, decreased appetite, and craving on stopping sustained heavy use — milder and less medically dangerous than alcohol or sedative withdrawal.

Psychotic disorder

Psychotic phenomena (delusions, hallucinations) occurring during or shortly after cannabis use, more sustained than simple intoxication, and not fully explained by intoxication alone.

Temporal relationship to use

The single most decisive piece of evidence for every F12 subtype — onset relative to use, and whether symptoms resolve as expected or persist well beyond it.

How to weigh evidence

These learning labels are teaching aids, not official ICD-10 terminology (see Sources and Method).

• supports Transient suspiciousness and perceptual distortion beginning during cannabis use and fully resolving within a few hours as the effects wore off.
• consistent not decisive The person uses cannabis regularly. Regular use alone does not establish either dependence or a psychotic disorder without the fuller criteria or a sustained psychotic picture.
• raises alternative Psychotic symptoms that began during a period of cannabis use but have persisted for several months after use stopped entirely.
• contradicts or weakens No family history, no prior psychotic episodes, and symptoms that resolved completely within a day of last use.
• missing and necessary to ask Whether psychotic symptoms have continued after a sustained period of abstinence, and whether there is a family or personal history of psychotic illness.

Duration and course

Minimum duration: Dependence syndrome, as elsewhere in this block, is typically established by three or more criteria present together within the past year.

Course: Intoxication effects typically resolve within hours; a cannabis-induced psychotic disorder is expected to resolve within days to a few weeks of abstinence, whereas symptoms persisting well beyond that window raise the question of an independent illness.

Included presentations

• Transient intoxication with perceptual, anxiety, or mild paranoid phenomena resolving as expected.
• A pattern meeting three or more dependence-syndrome criteria for cannabis use within the past year.
• A sustained psychotic picture temporally linked to cannabis use and resolving within the expected post-cessation window.

Exclusions and distinguishing presentations

Four-character subtypes (orientation)

A learner should not assign the psychotic-disorder subtype from perceptual change alone without checking duration and persistence beyond the expected intoxication or withdrawal window. Subtypes beyond F12.0 and F12.5 are taught here for orientation only and are not separately assessed in this pilot.

F12.0 — Acute intoxication

Transient perceptual, anxiety or mild paranoid phenomena during use, resolving within hours. (in_depth)

F12.1 — Harmful use

A pattern causing demonstrable harm without the fuller dependence cluster. (taught for orientation only, not separately assessed in this pilot)

F12.2 — Dependence syndrome

Three or more of the six dependence criteria present together within the past year. (taught for orientation only, not separately assessed in this pilot)

F12.3 — Withdrawal state

Irritability, sleep disturbance, decreased appetite and craving on stopping sustained heavy use. (taught for orientation only, not separately assessed in this pilot)

F12.4 — Withdrawal state with delirium

Rare with cannabis alone. (taught for orientation only, not separately assessed in this pilot)

F12.5 — Psychotic disorder

A sustained psychotic picture temporally linked to cannabis use, beyond simple intoxication. (in_depth)

F12.6 — Amnesic syndrome

Chronic memory impairment associated with sustained heavy use — less classically described than with alcohol. (taught for orientation only, not separately assessed in this pilot)

F12.7 — Residual and late-onset psychotic disorder

Cannabis-related changes persisting beyond the period of direct action. (taught for orientation only, not separately assessed in this pilot)

F12.8 — Other mental and behavioural disorders

A cannabis-related presentation not fitting the other listed states. (taught for orientation only, not separately assessed in this pilot)

F12.9 — Unspecified mental and behavioural disorder

A cannabis-related disturbance identified but without enough information to classify further. (taught for orientation only, not separately assessed in this pilot)

External causes to check first

Categories in this block require that the disturbance is not better explained by another external cause listed below. These short capsules are reminders, not full teaching modules.

Worked example — intoxication versus a substance-induced psychotic disorder

A 20-year-old university student used cannabis at a party and became convinced that other guests were talking about him and watching him, alongside mild visual distortions. He was noticeably anxious and suspicious for the rest of the evening. By the next morning, after sleeping it off, he reported feeling completely back to normal and could not understand what had come over him. He has no family history of psychotic illness and this was his first time using cannabis.

1. Step 1 — Check timing of onset: the suspiciousness and perceptual distortion began during use, which is consistent with an intoxication-related phenomenon rather than an independent process.
2. Step 2 — Check duration: the symptoms fully resolved by the next morning, well within the expected intoxication window, rather than persisting for days or weeks.
3. Step 3 — Check for risk factors for an independent illness: no family history and no prior psychotic episodes, weakening the case for an independent psychotic illness.
4. Step 4 — Weigh against F12.5: because the symptoms did not persist beyond the expected intoxication period, this does not meet the more sustained picture required for a psychotic disorder subtype.
5. Conclusion — This is best classified as acute intoxication (F12.0) with transient psychotic-quality phenomena, not a substance-induced psychotic disorder, because the symptoms were confined to, and resolved with, the intoxication period.

Interactive practice

• Type A Suspicious at the party, back to normal by morning Recognition / application · Foundation
• Type B Three weeks on, and still not right Boundary / differential · Boundary

Retrieval prompts

Try answering each of these from memory before revealing where to check. Nothing you think or type here is sent or saved anywhere.

1. Without looking back at the page, state the single most useful question for distinguishing intoxication from a cannabis-induced psychotic disorder.

   Reveal answer location

   Check Duration and course, Diagnostic boundary, or the rapid revision card below — the cue you need is one of those, in this category's own already-authored wording.

   I recalled this I need to review this

2. Name one feature that would raise concern about an independent psychotic illness rather than a substance-induced one.

   Reveal answer location

   Check Duration and course, Diagnostic boundary, or the rapid revision card below — the cue you need is one of those, in this category's own already-authored wording.

   I recalled this I need to review this

3. Explain in one sentence why regular cannabis use alone does not establish dependence syndrome.

   Reveal answer location

   Check Duration and course, Diagnostic boundary, or the rapid revision card below — the cue you need is one of those, in this category's own already-authored wording.

   I recalled this I need to review this

These self-checks are a personal study aid only, visible to you on this page for this visit — they are not stored and do not affect your mastery dimensions.

Related glossary terms

• Dependence syndrome

  A cluster of behavioural, cognitive, and physiological phenomena that develop after repeated substance use, in which use of that substance takes on a much higher priority than other behaviours that once had greater value. Classically established when three or more of six criteria (strong desire/compulsion, difficulty controlling use, tolerance, a physiological withdrawal state, progressive neglect of alternative interests, and continued use despite clear harm) have been present together within the past year.

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• Withdrawal state

  A group of symptoms, of variable severity and clustering, occurring on absolute or relative withdrawal of a substance after repeated, and usually prolonged and/or high-dose, use of that substance. Onset, timing, and medical danger vary considerably by substance.

  Open full glossary entry →