Stimulant and methamphetamine use

Overview and definition

Stimulant and methamphetamine use sits at the centre of addiction psychiatry, emergency psychiatry and dual-diagnosis work. The clinical job is not merely to name "ice use," but to define the disorder severity, map intoxication versus withdrawal versus substance-induced mental disorder, exclude life-threatening medical complications, manage behavioural disturbance safely, and deliver evidence-based psychosocial care while being honest about the thin pharmacotherapy evidence base.[1][2]

In DSM-5-TR, stimulant use disorder is diagnosed when a problematic pattern of amphetamine-type stimulant, cocaine or other stimulant use leads to clinically significant impairment or distress, with severity graded by criterion count (mild 2–3, moderate 4–5, severe 6 or more) over a 12-month period. ICD-11 frames a spectrum from hazardous use through harmful pattern of use to dependence, plus separate codes for substance-induced mental and behavioural disorders. Fellowship candidates must speak both languages and avoid equating any single positive urine drug screen with a use-disorder diagnosis.[1]

Classification

Clinically useful categories for viva and service design:

[1]

Methamphetamine-associated psychosis (MAP) is a clinical syndrome of delusions and/or hallucinations temporally linked to methamphetamine use. It may remit with abstinence or persist and force a dual formulation with primary psychotic disorder. DSM-5-TR substance-induced psychotic disorder requires that symptoms are not better explained by a primary psychotic disorder and that they develop during or soon after intoxication or withdrawal; examiners test the timeline and the evolution after confirmed abstinence.[7]

Epidemiology and risk factors

Methamphetamine remains a high-burden drug class in Australia and New Zealand, with crystal methamphetamine smoking and injecting patterns driving acute behavioural and medical presentations. Risk clusters include younger adults, male sex (with important exceptions such as chemsex networks), trauma histories, ADHD and externalising disorders, homelessness, criminal justice contact, and polysubstance use (alcohol, cannabis, GHB, opioids).[1]

Prospective longitudinal work shows dose-related psychotic symptoms in chronic methamphetamine users: periods of heavier use carry higher odds of psychotic experiences even after accounting for other factors.[7] The same research programme links methamphetamine use periods with elevated violent behaviour risk, reinforcing dynamic risk formulation rather than trait labelling.[8] Cardiovascular disease — acute coronary syndromes, cardiomyopathy, arrhythmias, stroke — is a major non-psychiatric mortality and morbidity pathway.[6]

Pathophysiology

Methamphetamine is a potent releaser and reuptake inhibitor of dopamine, noradrenaline and serotonin. It enters terminals via monoamine transporters and promotes reverse transport, dumping monoamines into the synapse. The resulting striatal dopamine surge underpins intense reinforcement, binge patterning and compulsive re-dosing. Relative to cocaine, methamphetamine has a longer half-life and greater potential for sustained monoaminergic stress and neurotoxicity signals.[6]

Psychosis risk is conceptualised as state-related dopaminergic and broader monoaminergic dysregulation, modulated by dose, frequency, sleep deprivation, concurrent cannabis, and vulnerability (including familial psychosis liability). Peripheral catecholamine excess explains acute tachycardia, hypertension, vasoconstriction and the pathway to myocardial ischaemia, arrhythmia and dilated cardiomyopathy with heavy use.[6][7]

Clinical presentation

Intoxication

Typical intoxication features: euphoria or irritability, increased energy, decreased need for sleep, hypervigilance, pressured speech, mydriasis, tachycardia, hypertension, bruxism, reduced appetite, and at higher doses agitation, paranoia and hallucinations. Severe toxicity includes hyperthermia, seizures, stroke, acute coronary syndrome and excited delirium-type presentations — medical stabilisation first.[17]

Withdrawal and crash

Unlike alcohol or benzodiazepine withdrawal, methamphetamine withdrawal is not typically epileptogenic or autonomically life-threatening, but it is clinically important. Classic description (McGregor et al.): an initial crash with profound fatigue and increased sleep, then a peak of dysphoria, anhedonia, irritability, craving and sleep disturbance around the second day, with symptoms generally improving over about one to two weeks though residual sleep and mood symptoms may linger.[9] Suicide risk can rise in the crash — schedule safety review, not "watch and wait" discharge without a plan.

Methamphetamine-associated psychosis

MAP commonly features persecutory delusions, auditory hallucinations, ideas of reference and formication (tactile "bugs under skin") often with relatively clear consciousness. Symptoms are more likely during high-dose periods and may fluctuate with use intensity.[7] Persistent psychosis after days of abstinence forces careful dual diagnosis work rather than automatic reclassification as lifelong schizophrenia on day one — and equally forbids complacent discharge without follow-up.

Differential diagnosis

[7] [17]

Can't-miss organic differentials: ACS, aortic syndromes, intracranial haemorrhage, seizure, encephalitis, HIV and syphilis-related presentations, rhabdomyolysis with AKI, and hypoglycaemia or other metabolic derangement.[6][17]

Clinical and bedside assessment

Structure the assessment like any high-risk dual-diagnosis encounter:

1. Safety first — observations, airway risk if sedated, weapons/means, child protection, vulnerability.
2. Substance timeline — agent, route (smoke, inject, snort, oral), quantity/frequency, last use, binge length, polysubstance, prior MAP, prior overdoses.
3. MSE with examples — not "paranoid"; e.g. "believes neighbours laser-map his flat and hears third-person commentary; consciousness clear; orientation intact."
4. Risk — suicide (especially crash), violence (dynamic with heavy use), absconding, sexual exploitation, driving.
5. Capacity and legal status — jurisdiction-specific mental health and emergency detention frameworks; name principles, do not invent section numbers for the wrong country.
6. Collateral — family, ambulance, police, GP, AOD services, needle-syringe programmes.
7. Dual diagnosis screen — primary psychosis, bipolar, ADHD, PTSD, depression, personality disorder, intellectual disability.

[1] [8] [17]

Investigations

[1] [6] [17]

Management — resuscitation and acute care

Acute priorities:

1. ABC and medical stabilisation — cooling for hyperthermia, cardiac work-up, fluids and CK monitoring for rhabdomyolysis, seizure management per local emergency protocols.
2. Behavioural emergency ladder — low-stimulus environment, clear communication, verbal de-escalation, oral medication first when safe, parenteral medication only when needed under local rapid-tranquillisation guidance; avoid unnecessary restraint; continuous observation for deterioration.
3. Acute MAP — if psychosis is dangerous or persists and medical causes are addressed, a time-limited antipsychotic can reduce positive symptoms; network meta-analysis supports antipsychotic efficacy signals in MAP with attention to dropout and side-effects. Reassess within days; do not default to indefinite high-dose polypharmacy without dual-diagnosis review.
4. Suicide and violence plan — observation level, means restriction, early family contact, crisis pathway.

[13] [17]

Management — definitive and stepwise

Psychosocial treatments (first-line)

ASAM/AAAP guidance positions psychosocial interventions as the backbone of stimulant use disorder care. There is no FDA-approved standard pharmacotherapy analogous to opioid agonist treatment.[1] Systematic review-of-reviews work reaches the same practical conclusion: psychosocial approaches carry the most consistent support; medication signals are mixed and context-limited.[2]

Contingency management (CM) — systematic positive reinforcement (e.g. vouchers or prizes contingent on stimulant-negative urine samples or treatment adherence) — has the strongest psychosocial evidence signal across drug use disorders and is repeatedly highlighted for stimulants.[11][12] Australian service reflections note implementation barriers (funding, culture, training) despite clinical interest — viva candidates should name CM and the system barriers, not only the RCT ideal.[18]

CBT, community reinforcement approach (CRA), and the Matrix model multi-element outpatient package (CBT skills, family education, urine monitoring, therapist support) have multi-site methamphetamine programme evidence; Rawson and colleagues showed psychosocial package benefits in methamphetamine dependence treatment settings.[10][11]

Motivational interviewing, peer support, housing first approaches, and sexual health / harm-reduction packages (wound care, safer-use information without moralising, STI/HIV care, naloxone if opioid co-use) are core public-health psychiatry, not optional extras.[1]

Pharmacotherapy — limited evidence, state clearly

Be precise in exams: no agent is a licensed, guideline-mandated first-line anti-craving standard for methamphetamine in the way methadone/buprenorphine is for opioids.[1][16]

Reduced use (not only continuous abstinence) is an emerging trial outcome of clinical relevance; interpret pharmacotherapy literature with that endpoint literacy.[20]

Dual diagnosis and integrated care

Never withhold treatment of acute psychosis, mania or severe depression pending mythical perfect abstinence. Integrated mental health and alcohol-and-other-drug (AOD) care with shared formulation outperforms sequential "treat one then the other" pathways in principle and in dual-diagnosis guidance culture across ANZ/UK systems.[1][16]

Specific subtypes and scenarios

Crystal meth binge with behavioural disturbance. Medical obs, de-escalation, short-acting sedation per local protocol if needed, MAP assessment, overnight observation for crash suicidality.[17]

Persistent MAP after abstinence. Re-open organic work-up thresholds, family history, cognitive baseline, early intervention or dual-diagnosis follow-up; consider whether criteria for primary psychotic disorder are emerging.[7]

Chemsex (meth ± GHB ± other). Sexual risk, consent capacity while intoxicated, GHB withdrawal risk if dependent, stigma-sensitive engagement, STI/HIV pathways.[1]

Prescription stimulant diversion. Separate legitimate ADHD treatment (supervised, functional gains) from misuse; do not abruptly abandon genuine ADHD care without a plan.[1]

Cocaine interface. Shorter action, intense craving cycles; CM still central; CV risk remains high.[1][12]

Methamphetamine cardiomyopathy. Coordinate cardiology; counsel that continued use worsens prognosis; psychiatric engagement is part of secondary prevention.[6]

Custody / forensic transfer. Document intoxication stage, MAP, risk, medication given, and observation needs at handover.[8][17]

Complications and pitfalls

• Medical: ACS, cardiomyopathy, arrhythmia, stroke, hyperthermia, rhabdomyolysis, dental destruction, skin infections, blood-borne viruses.
• Psychiatric: MAP, crash depression and suicide, anxiety, cognitive complaints, trauma re-enactment.
• Pitfalls: lifelong schizophrenia label after a single MAP episode; refusing antipsychotics when dangerous psychosis is present; inventing a "meth detox protocol" with unproven high-dose polypharmacy; missing ACS in a 28-year-old; discharging a crashing patient without suicide assessment; punitive discharge without AOD follow-up; ignoring CM because "we do not have vouchers" without any reinforcement strategy.

[6] [7] [9] [12]

Prognosis and disposition

Prognosis tracks severity and route of use, social capital (housing, relationships), dual diagnosis, treatment access (especially CM-capable services), and engagement. Disposition is a ladder: medical clearance → psychiatric emergency observation or inpatient unit if high risk → community shared care (mental health + AOD) with early review after MAP or suicidal crash. Recovery endpoints include reduced use or abstinence, retained housing, vocational roles and restored relationships — not urine purity alone.[1][20]

Special populations

Youth. High MAP and first-episode psychosis interface; family work; avoid diagnostic fatalism.[1][7]

Pregnancy. Prioritise psychosocial care, obstetric liaison, and harm reduction; do not invent unproven pharmacotherapy as standard; counsel fetal and maternal CV risks of continued meth use.[1]

Older adults. Lower prevalence but high CV vulnerability; covert use possible.[6]

Indigenous and culturally diverse communities (ANZ). Partner with culturally safe and community-controlled services; address social determinants; avoid deficit-only framing.[1][18]

Intellectual disability / autism. Behavioural crisis may reflect pain, fear or sensory load plus intoxication — adapt communication.[1]

Forensic. Dynamic risk, MAP, and medication handover dominate.[8]

Evidence, guidelines and regional differences

Exam pearls

• No methadone equivalent for meth — saying "start substitution therapy" without nuance fails.[1]
• Name contingency management as the highest-yield psychosocial modality for stimulants.[12]
• MAP is dose-related; clear consciousness helps separate from delirium.[7]
• Withdrawal is usually not seizures-like alcohol — but suicide and CV events still kill.[9][6]
• If you quote ADAPT-2, state naltrexone XR 380 mg IM every 3 weeks + bupropion XL 450 mg daily accurately, with exclusions.[3]
• If you quote mirtazapine trials, 30 mg nocte is the common studied dose — cite, do not invent alternatives as if universal protocol.[4][5]
• Violence risk is dynamic with heavy use periods.[8]
• Legal frameworks are jurisdiction-specific — principles yes, invented section numbers no.[1]
• Integrated dual diagnosis: treat both, do not wait for perfect abstinence.[1][16]

References

1. [1]ASAM/AAAP Clinical Guideline Committee The ASAM/AAAP Clinical Practice Guideline on the Management of Stimulant Use Disorder J Addict Med, 2024.PMID 38669101
2. [2]Ronsley C, Nolan S, Knight R, et al. Treatment of stimulant use disorder: A systematic review of reviews PLoS One, 2020.PMID 32555667
3. [3]Trivedi MH, Walker R, Ling W, et al. Bupropion and Naltrexone in Methamphetamine Use Disorder N Engl J Med, 2021.PMID 33497547
4. [4]Coffin PO, Santos GM, Hern J, et al. Effects of Mirtazapine for Methamphetamine Use Disorder Among Cisgender Men and Transgender Women Who Have Sex With Men: A Randomized Clinical Trial JAMA Psychiatry, 2020.PMID 31825466
5. [5]Colfax GN, Santos GM, Das M, et al. Mirtazapine to reduce methamphetamine use: a randomized controlled trial Arch Gen Psychiatry, 2011.PMID 22065532
6. [6]Kevil CG, Goeders NE, Woolard MD, et al. Methamphetamine Use and Cardiovascular Disease Arterioscler Thromb Vasc Biol, 2019.PMID 31433698
7. [7]McKetin R, Lubman DI, Baker AL, et al. Dose-related psychotic symptoms in chronic methamphetamine users: evidence from a prospective longitudinal study JAMA Psychiatry, 2013.PMID 23303471
8. [8]McKetin R, Lubman DI, Najman JM, et al. Does methamphetamine use increase violent behaviour? Evidence from a prospective longitudinal study Addiction, 2014.PMID 24400972
9. [9]McGregor C, Srisurapanont M, Jittiwutikarn J, et al. The nature, time course and severity of methamphetamine withdrawal Addiction, 2005.PMID 16128721
10. [10]Rawson RA, Marinelli-Casey P, Anglin MD, et al. A multi-site comparison of psychosocial approaches for the treatment of methamphetamine dependence Addiction, 2004.PMID 15139869
11. [11]Dutra L, Stathopoulou G, Basden SL, et al. A meta-analytic review of psychosocial interventions for substance use disorders Am J Psychiatry, 2008.PMID 18198270
12. [12]Pfund RA, Ginley MK, Boness CL, et al. Contingency Management for Drug Use Disorders: Meta-Analysis and Application of Tolin's Criteria Clin Psychol (New York), 2024.PMID 38863566
13. [13]Srisurapanont M, Likhitsathian S, Suttajit S, et al. Efficacy and dropout rates of antipsychotic medications for methamphetamine psychosis: A systematic review and network meta-analysis Drug Alcohol Depend, 2021.PMID 33385693
14. [14]McKetin R, Dean OM, Turner A, et al. N-acetylcysteine (NAC) for methamphetamine dependence: A randomised controlled trial EClinicalMedicine, 2021.PMID 34308314
15. [15]McKetin R, Shoptaw S, Saunders L, et al. Mirtazapine for Methamphetamine Use Disorder: A Randomized Clinical Trial JAMA Psychiatry, 2026.PMID 41920558
16. [16]Sinclair JMA, Kalk NJ, Kaar SJ, et al. Evidence-based consensus guidelines for the pharmacological management of substance dependence: Recommendations from the British Association for Psychopharmacology J Psychopharmacol, 2026.PMID 41731947
17. [17]Fries A, Christ M, Nickl H, et al. The Diagnosis and Treatment of Stimulant-Related Emergencies Dtsch Arztebl Int, 2025.PMID 40991352
18. [18]Clay S, Wilkinson Z, Ginley M, et al. The reflections of health service providers on implementing contingency management for methamphetamine use disorder in Australia Drug Alcohol Rev, 2024.PMID 38704742
19. [19]Khalili M, Sadeghirad B, Bach P, et al. Management of Amphetamine and Methamphetamine Use Disorders: A Systematic Review and Network Meta-analysis of Randomized Trials Int J Ment Health Addict, 2025.PMID 41394525
20. [20]Amin-Esmaeili M, Farokhnia M, Mojtabai R, et al. Evaluating Reduced Use and Abstinence as Outcomes in Pharmacotherapy Trials for Stimulant Use Disorder: A Meta-Analysis of 12 Randomized Clinical Trials JAMA Psychiatry, 2026.PMID 42234418