Substance-induced psychosis

Abrupt onset after cannabis, methamphetamine, cocaine, hallucinogens, steroids, or withdrawal

UrgentReview due

Compare (7)

At a glance

High-risk causes: 4
Core tests: 3
Immediate actions: 6
Related differentials: 6

Safety snapshot

Watch forHyperthermiachest painviolent agitationpersistent psychosis

Presentation hinge

Inattention and fluctuation dominate. Psychotic content is often fragmented or changeable.

Separates the Psychosis / First-Episode Medical Psychosis group. It is not specific to Substance-induced psychosis.

Points for this presentation

Applies to the Psychosis / First-Episode Medical Psychosis group — not specific to Substance-induced psychosis

In older or medically unwell patients, assume delirium until proved otherwise
Cannabis and stimulants can closely mimic primary psychosis
Reassess once partially cleared
Escalate early to medical/neurology review if red flags are present

Clinical review

Rows marked “Whole group”: Applies to the Psychosis / First-Episode Medical Psychosis group — not specific to Substance-induced psychosis

Why it fits

Abrupt onset after cannabis, methamphetamine, cocaine, hallucinogens, steroids, or withdrawal

Key features

Must-not-miss

Hyperthermia, chest pain, violent agitation, persistent psychosis.

High-risk causes4 causes

Hyperthermia
chest pain
violent agitation
persistent psychosis

Bedside question

Applies to the Psychosis / First-Episode Medical Psychosis group.

Inattention and fluctuation dominate. Psychotic content is often fragmented or changeable.

Helpful clues

Immediate action

Applies to the Psychosis / First-Episode Medical Psychosis group.

In older or medically unwell patients, assume delirium until proved otherwise Cannabis and stimulants can closely mimic primary psychosis Reassess once partially cleared Escalate early to medical/neurology review if red flags are present Consider MRI, EEG, CSF, and autoimmune testing when the syndrome is atypical Clarify positive symptoms, negative symptoms, cognition, and functional trajectory

Priority steps6 steps

1In older or medically unwell patients, assume delirium until proved otherwise
2Cannabis and stimulants can closely mimic primary psychosis
3Reassess once partially cleared
4Escalate early to medical/neurology review if red flags are present
5Consider MRI, EEG, CSF, and autoimmune testing when the syndrome is atypical
6Clarify positive symptoms, negative symptoms, cognition, and functional trajectory

Investigations

Applies to the Psychosis / First-Episode Medical Psychosis group.

Neuroimaging (CT/MRI), EEG, Lumbar puncture / CSF studies

Core tests3

Neuroimaging (CT/MRI)
EEG
Lumbar puncture / CSF studies

Mimics / overlap

Applies to the Psychosis / First-Episode Medical Psychosis group.

None listed

Consider

Points for this presentation

Applies to the Psychosis / First-Episode Medical Psychosis group — not specific to Substance-induced psychosis

In older or medically unwell patients, assume delirium until proved otherwise
Cannabis and stimulants can closely mimic primary psychosis
Reassess once partially cleared
Escalate early to medical/neurology review if red flags are present

First-line tests

Applies to the Psychosis / First-Episode Medical Psychosis group — not specific to Substance-induced psychosis

Neuroimaging (CT/MRI)
EEG
Lumbar puncture / CSF studies

Watch for

Hyperthermia
chest pain
violent agitation
persistent psychosis

Also consider

Source and review

Review due· Unverified

v10 · exported 2026-07-11

Clinical reference — not validated decision support. Review before use.