Substance-induced psychotic disorder

Overview - The Unwanted Trip

• Psychotic symptoms (hallucinations, delusions) directly triggered by substance intoxication or withdrawal.
• Symptoms emerge during use or within 1 month of stopping the substance.
• Not better explained by a primary psychotic disorder.
• Common Triggers:
  • Stimulants: Cocaine, amphetamines (often paranoid delusions).
  • Hallucinogens: LSD, PCP (visual/auditory hallucinations).
  • Cannabis: High-potency THC can induce paranoia.
  • Withdrawal: Alcohol, benzodiazepines, barbiturates.
• Clinical picture is key; presentation mirrors the toxidrome of the causative agent.

⭐ High-Yield: A temporal link is crucial for diagnosis. The psychotic symptoms must begin after the substance use started and typically resolve within 1 month of cessation. Persistence beyond this window suggests an underlying primary psychotic disorder.

Causative Agents - The Usual Suspects

• Stimulants: Cocaine, amphetamines, and methamphetamine are classic triggers.
  • Presentation is often paranoid with prominent hallucinations.
• Cannabis: High-potency THC is strongly linked, especially in genetically vulnerable individuals.
• Hallucinogens: By definition, these induce altered perceptions.
  • LSD, psilocybin, and dissociatives like PCP and ketamine.
• Alcohol: Most common during withdrawal (delirium tremens), but can occur with severe intoxication.
• Sedative/Hypnotic/Anxiolytic Withdrawal: Abrupt cessation of benzodiazepines or barbiturates.
• Prescription Drugs: Corticosteroids, antiparkinsonian agents (L-dopa), and anticholinergics.

⭐ Tactile hallucinations, especially formication (the sensation of insects crawling on the skin), are a hallmark of cocaine and amphetamine-induced psychosis.

Diagnosis - Spotting the Impostor

• Core Feature: Presence of prominent hallucinations and/or delusions.
• Crucial Link (Temporal): Symptoms develop during or soon after substance intoxication or withdrawal. The substance must be known to be capable of producing psychotic symptoms.
• Key Investigations: A thorough substance use history and a Urine Drug Screen (UDS) are essential.

⭐ Exam Favorite: The 1-month rule is key. If psychotic symptoms persist for more than 1 month after the cessation of substance use, the diagnosis is more likely a primary psychotic disorder like schizophrenia, not substance-induced psychosis.

Management - The Clean-Up Crew

• Primary Goal: Stop the substance & ensure patient safety.
  • Provide supportive care in a low-stimulus environment.
  • Benzodiazepines (e.g., lorazepam) are first-line for agitation.
• For Severe/Persistent Psychosis:
  • Use antipsychotics (e.g., olanzapine, haloperidol) for short-term symptom control.

⭐ Psychotic symptoms that persist for > 1 month after substance cessation suggest a primary psychotic disorder, not a substance-induced one.

High‑Yield Points - ⚡ Biggest Takeaways

• Psychosis is directly attributable to substance intoxication or withdrawal.
• Symptoms like hallucinations (often visual) and delusions emerge during or shortly after substance use.
• Common triggers include amphetamines, cocaine, cannabis, and alcohol withdrawal.
• Differentiate from primary psychosis: symptoms are temporary and resolve after the substance's effects cease.
• The temporal link is key: psychosis would not occur without the substance.
• Management focuses on stopping the substance and supportive care; short-term antipsychotics may be needed.