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Clinical Atlas Prestige · Evidence-first

Psych MEQs / SAQsAddiction psychiatry — hallucinogen-related disorders

Psych MEQs / SAQs · Addiction psychiatry — hallucinogen-related disorders

Hallucinogen-related disorders — bad trip, HPPD, and PAT interface (MEQ)

FRANZCP-style MEQ on classic psychedelic intoxication, talk-down care, dual formulation of psychosis, HPPD, and accurate reading of PAT trials versus recreational use.

20 marks20 min
On this page & tools

Target exams

FRANZCPMRCPsychABPNMD-DNB

Target exams

FRANZCPMRCPsychABPNMD-DNB
Prompt
A 24-year-old man is brought from a multi-day music festival after ingesting blotter sold as LSD plus cannabis. HR 108, BP 138/84, temperature 37.2°C, glucose normal. He is oriented, mydriatic, terrified that the stage lights are scanning his thoughts, and tries to run toward a road. Friends report this is his third lifetime psychedelic use; no prior psychiatric admissions; maternal uncle has schizophrenia. Effects peak over several hours then settle with talk-down and a single oral lorazepam 1 mg. Two months later he re-presents with constant visual trailing and geometric patterns while abstinent, with occupational impairment and secondary anxiety. He asks whether microdosing will fix his 'depression' after reading about psilocybin trials. (i) Outline acute assessment and management priorities for the festival presentation. (ii) Formulate psychosis risk and dual formulation issues given the family history. (iii) Define HPPD and initial management. (iv) Explain the evidence interface with psychedelic-assisted therapy and why unsupervised microdosing is not appropriate. (v) List disposition and harm-reduction advice. (20 marks)

Model answer

Reveal model answer

(i) Acute assessment and management. ABC and medical exclusion first (vitals, glucose already done; watch for adulterant toxicity, hyperthermia, trauma, MDMA co-toxidrome if history expands). Secure environment to prevent road injury. Low-stimulus setting, calm talk-down, continuous observation through expected peak; time-limited benzodiazepine (here lorazepam 1 mg orally) for severe panic/agitation when support alone is insufficient. Antipsychotic not automatic for every perceptual change. Do not start "hallucinogen detox" seizure protocols. Document substance timeline, capacity and risk.[1][2]

(ii) Psychosis risk and dual formulation. Acute persecutory content temporally linked to claimed LSD with relatively clear orientation favours substance-related intoxication/psychotic symptoms rather than proven lifelong primary schizophrenia on day one. Maternal uncle with schizophrenia elevates vulnerability and mandates honest risk counselling and longitudinal follow-up — dual formulation remains open if symptoms persist after washout. Family pressure for immediate lifelong depot is a trap; use timeline, collateral and planned review.[5]

(iii) HPPD definition and management. Re-experiencing of perceptual phenomena (trailing, geometric patterns) after cessation, with distress and occupational impairment, fits HPPD rather than ongoing intoxication. Validate; exclude alternative visual/neurological causes as indicated; advise ongoing abstinence from hallucinogens and ideally cannabis; treat secondary anxiety; evidence for specific anti-HPPD drugs is limited/case-level — avoid inventing a mandatory complex polypharmacy algorithm.[3][4]

(iv) PAT evidence interface. Protocolised trials (e.g. Goodwin: single 25 mg oral psilocybin superior to 1 mg control at 3 weeks on primary depression outcome in TRD under research conditions with support) are not equivalent to unsupervised microdosing. Explain screening, preparation, session support and integration; legal and safety limits in ANZ standard care; offer evidence-based depression pathways instead of colluding with illicit supply.[1][6]

(v) Disposition and harm reduction. Discharge only when MSE safe and supports available; written advice on set/setting, dose uncertainty/adulterants, no driving while residual effects, avoid use given family psychosis risk and HPPD, AOD brief intervention, dual-diagnosis or early-intervention follow-up, crisis contacts, ophthalmology/neurology thresholds if visual differential unclear.[1][3][5]

Common errors

  • Treating classic psychedelic distress as alcohol withdrawal seizure detox.
  • Lifelong schizophrenia label after a single linked episode without timeline.
  • Equating PAT trial headlines with unsupervised microdosing scripts.
  • Dismissing impairing post-cessation visual phenomena as trivial flashbacks.
  • Missing injury risk (roads, heights) during the bad trip. [1][3][6]

Examiner notes

Full marks require medical exclusion plus talk-down ladder, dual formulation with family-risk counselling, accurate HPPD definition/management limits, precise PAT trial reading (25 mg signal under protocol, not DIY), and harm-reduction disposition. [1][3][6]

References

  1. [1]Johnson MW, Richards WA, Griffiths RR Human hallucinogen research: guidelines for safety J Psychopharmacol, 2008.PMID 18593734
  2. [2]Nichols DE Psychedelics Pharmacol Rev, 2016.PMID 26841800
  3. [3]Halpern JH, Pope HG Jr Hallucinogen persisting perception disorder: what do we know after 50 years? Drug Alcohol Depend, 2003.PMID 12609692
  4. [4]Martinotti G, Santacroce R, Pettorruso M, et al. Hallucinogen Persisting Perception Disorder: Etiology, Clinical Features, and Therapeutic Perspectives Brain Sci, 2018.PMID 29547576
  5. [5]Carbonaro TM, Bradstreet MP, Barrett FS, et al. Survey study of challenging experiences after ingesting psilocybin mushrooms: Acute and enduring positive and negative consequences J Psychopharmacol, 2016.PMID 27578767
  6. [6]Goodwin GM, Aaronson ST, Alvarez O, et al. Single-Dose Psilocybin for a Treatment-Resistant Episode of Major Depression N Engl J Med, 2022.PMID 36322843