Substance-induced psychosis — structured clinical viva

Assessment spine. Medical exclusion first (cardiovascular, hyperthermia, seizure risk with stimulants), timeline of last use and dose pattern, collateral, MSE, risk (violence and suicide including crash phase), capacity/legal status, dual diagnosis of stimulant use disorder if criteria met. McKetin evidence: psychotic symptoms are dose-related in chronic methamphetamine users.[3]

"Is this schizophrenia forever?" Use provisional pathway language: working diagnosis may be substance-induced psychotic disorder if the temporal link is clear and organicity is excluded; diagnosis can evolve if symptoms persist after abstinence. Avoid fatalism and avoid dismissiveness.[1]

"Why an antipsychotic?" Psychosis and agitation still cause risk and suffering; short-to-medium term antipsychotic (name e.g. olanzapine 5–10 mg oral nocte or risperidone 1–2 mg with baselines) treats symptoms while substance cessation proceeds. Positive UDS is not a reason to withhold treatment.[3]

Conversion risk. Quote Starzer (~32% overall convert to schizophrenia-spectrum or bipolar; cannabis highest) and Murrie (pooled ~25% SIP→schizophrenia; amphetamines in the higher band). Self-harm and young age increase conversion risk. Follow-up must be dual-aware over months to years.[1][2]

"Addiction first, psychiatry later?" No — integrated concurrent care. Sequential exclusion worsens outcomes; shared formulation, MI/psychosocial SUD work plus psychosis treatment together.[4]