MEQ: BPS and 4P formulation for first-episode psychosis with cannabis

(i) Definition and distinction (3). Psychiatric case formulation is a hypothesis-driven, individualised explanatory account of why this person has these problems now, integrating multi-domain data to guide intervention and communication. Diagnosis classifies a syndrome for communication, epidemiology, and evidence application. Diagnosis is necessary but not sufficient for personalised care; formulation bridges generic evidence and the individual without replacing risk or capacity assessment.^[1][2]

(ii) BPS × 4P formulation (8).

Presenting problem. First-episode psychosis (positive symptoms, functional collapse) with heavy cannabis use and family conflict; differential remains open to substance-induced and other organic contributions pending work-up.

Predisposing. Biological: first-degree family history of schizophrenia (genetic vulnerability). Psychological: possible pre-morbid social vulnerability (implied by rapid isolation under stress). Social: developmental context to be expanded; structural student stress.

Precipitating. Daily high-potency cannabis; severe sleep restriction in exam week; academic stress as tip-over context.

Perpetuating. Ongoing cannabis; sleep debt; untreated psychosis; social withdrawal; parental high expressed emotion / conflicting illness explanations that may increase stress and reduce consistent support.

Protective. Engaged sister; still attending (brought to clinic); university role as potential future scaffold; absence of described forensic violence history in stem (still assess risk fully).

Mechanisms (brief). Diathesis (family loading) + cannabis/sleep stress lowered psychosis threshold; positive symptoms and paranoia drive withdrawal; withdrawal and family conflict maintain arousal and reduce reality-testing opportunities; competing explanatory models (spirits vs system) affect help-seeking and alliance.^[1][2][3]

(iii) Mapped plan (6).

• Biological: medical/organic screen appropriate to FEP; discuss antipsychotic trial targeting positive symptoms and sleep restoration; cannabis psychoeducation and harm-reduction/cessation support; sleep interventions.
• Psychological: psychoeducation about psychosis; collaborative formulation in plain language; CBT for psychosis elements when engagement allows; motivational work for cannabis.
• Social/family: family psychoeducation to lower EE and align a shared illness model; involve sister as support; education/university liaison when stable; practical supports.
• Cultural/meaning: explore illness explanations (spirits/system) with curiosity (CFI-style); do not ridicule; negotiate a shared care plan that respects meaning while offering medical model as additional frame.
• Risk: full suicide/violence/vulnerability assessment; safety plan; intensity of follow-up matched to risk and supports; least-restrictive setting that is safe.
• Review: rewrite formulation after abstinence attempt, treatment response, and collateral.^[1][4][5]

(iv) Evidence anchors (3). Examples: Engel on biopsychosocial levels; Macneil et al. on formulation beyond diagnosis; Owen on what formulation is; Lewis-Fernández CFI field trial / OCF operationalisation for cultural assessment.^[1][2][3][4]