Dual diagnosis — models of care to integrated recovery (MEQ)

(i) Definition and care models. Dual diagnosis = co-occurring mental disorder and substance use disorder. Sequential: treat one disorder fully then the other (here: refuse MH until abstinence) — historically common, often fails. Parallel: separate MH and AOD services at once without integration — risk of conflicting plans. Integrated: same team or tightly coordinated concurrent treatment of both conditions in one package — preferred default.[1]

(ii) Stage and MI. Daily high-THC use with no intent to change = precontemplation.[3] Use motivational interviewing: partnership, empathy, develop discrepancy (psychosis relapses vs cannabis goals), roll with sustain talk, support self-efficacy; OARS skills. Do not discharge; continue psychiatric alliance while opening substance conversation.[4]

(iii) Etiological models. Mueser et al.: common factor (shared vulnerability); secondary SUD (mental illness → substance use, including partial self-medication); secondary psychiatric (substance → mental illness; high-THC cannabis relevant); bidirectional mutual worsening. Formulate this man with likely bidirectional/secondary psychiatric contributions plus ongoing relapse driver from continued use.[2][6]

(iv) Integrated plan. Concurrent antipsychotic care with monitoring; MI-based cannabis counselling (frequency/potency); family psychoeducation; shared care plan ending ping-pong; harm reduction; housing/vocational supports; risk assessment (suicide, vulnerability); crisis plan. Systems: no-wrong-door, dual-trained staff or co-located services, joint governance — not sequential 28-day clean rules.[1][6]

(v) Recovery and evidence honesty. Recovery = symptoms, reduced substance harm/abstinence when chosen, housing, roles, relationships, hope — not urine purity alone. Cochrane psychosocial dual reviews show limited heterogeneous RCT superiority of specific packages over standard care — still treat concurrently; do not use evidence limits to justify gatekeeping.[5]