Early-onset psychosis — CAP assessment to clozapine threshold (MEQ)

(i) Definitions and DUP. Early-onset psychosis is frank psychotic disorder with onset before age 18; very-early-onset / childhood-onset schizophrenia is conventionally onset before 13. This 14-year-old sits in the EOP band (not VEOP). Working label: first-episode schizophrenia-spectrum psychosis with dual substance and autism comorbidity — provisional until duration and course clarify. DUP is at least about 10 weeks of frank psychosis (phone tracking, commentary); longer if school failure counts toward untreated illness definitions. Longer DUP associates with poorer outcomes — treatment should start now to stop the clock.^[1][5]

(ii) Differential with discriminators. Not "just autism": lifelong ASD may explain baseline social-communication style, but new fixed delusions, commentary hallucinations and functional collapse indicate a psychotic episode needing dual formulation. Trauma/PTSD: trauma timeline, flashbacks, dissociation. Substance: weekend high-THC may contribute but does not exclude primary illness; dual formulation. Organic: currently no fever/seizure/fluctuating attention, but keep encephalitis pathway if red flags emerge. Also consider affective psychosis and OCD with poor insight.^[1]

(iii) Investigations. Baseline before antipsychotic: weight/BMI (growth chart), BP, glucose or HbA1c, lipids, FBC, U&E, LFT, thyroid as indicated, ECG QTc, pregnancy test if applicable, substance history; urine drug screen supports never excludes. Escalate neuroimaging/EEG/LP/autoimmune panel if fever, seizure, focal neurology, rapid cognitive decline, catatonia or very atypical course.^[1][4]

(iv) Antipsychotic plan. Example: aripiprazole started low (youth-appropriate titration toward an effective range such as around 10 mg daily depending on age/weight and product guidance), after baselines, with education about akathisia. Trial about 4–6 weeks at therapeutic dose with adherence support. Alternatives guided by TEOSS-style evidence and side-effect profiles (risperidone prolactin/EPS; olanzapine high metabolic burden — monitor hard). First-time SGA exposure in youth drives early cardiometabolic risk — weight every visit initially.^[2][4]

(v) Multi-element care and clozapine threshold. Youth EIS/CAMHS package: low-dose medication, family psychoeducation, school liaison plan, cannabis motivational work, case management, psychological therapy access, safety plan. Cannabis cessation is secondary prevention. If two adequate adherent trials fail, escalate toward clozapine (Kumra evidence in refractory early-onset schizophrenia) rather than endless non-clozapine cycling.^[1][3][6]