First-Episode Psychosis in a 17-Year-Old: Antipsychotic Choice and Metabolic Risk
A 17-year-old girl is brought by her parents after 5 months of social withdrawal, declining grades, and 3 weeks of the belief that her neighbors are transmitting thoughts through the walls. She is otherwise healthy. BMI 31 (weight 92 kg, height 1.72 m), fasting glucose 104 mg/dL, HbA1c 5.9%, LDL 128 mg/dL, prolactin normal, no prior antipsychotic exposure. She is tearful, has passive suicidal ideation without plan, and denies substance use (urine toxicology negative). Her parents ask about "the safest medication" and whether she can "just do therapy." The family has limited transportation and can attend monthly visits.
1. What is the diagnostic formulation, and how does it shape treatment selection?
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This is a first-episode psychosis with a 5-month prodrome and 3 weeks of frank psychotic symptoms (thought broadcasting, functional decline). The differential includes schizophrenia spectrum, bipolar disorder with psychotic features, major depression with psychotic features, and medical/substance causes (already largely excluded).
Formulation drives selection because:
- Duration and functional decline suggest a schizophrenia-spectrum illness, but mood symptoms require screening for bipolarity before choosing treatment.
- First episode warrants lowest effective dose and metabolic-sparing agent, given her BMI 31, prediabetes (HbA1c 5.9%), and dyslipidemia.
- Suicidal ideation requires safety planning and close follow-up.
- Limited transportation argues for a long-acting injectable (LAI) option and telehealth supplementation.
Diagnosis should be revisited over time; a structured diagnostic interview and collateral from school are useful.
2. Which antipsychotic would you choose, and how do you justify it against her metabolic profile?
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Given obesity, prediabetes, and dyslipidemia, the priority is a metabolically favorable antipsychotic.
Reasonable first-line options:
- Aripiprazole (partial D2 agonist; low metabolic risk, low sedation) - often preferred in first episode.
- Lurasidone (low metabolic risk; take with food ≥350 kcal).
- Ziprasidone (low metabolic risk; requires food and ECG monitoring for QTc).
Avoid or use with caution:
- Olanzapine and clozapine - highest metabolic risk; reserve for treatment resistance.
- Quetiapine - moderate metabolic risk and sedation.
- Risperidone/paliperidone - moderate weight gain and hyperprolactinemia.
Justification: in a first episode with prediabetes, the number needed to harm for weight gain and dysglycemia is low, and metabolic effects are dose- and duration-dependent. Start low (e.g., aripiprazole 5 mg daily, titrate to 10 mg) and monitor.
Also address lifestyle: nutrition, activity, and baseline and 3-month metabolic monitoring (weight, BMI, waist, BP, fasting glucose/HbA1c, lipids). Consider metformin if weight gain occurs.
3. How do you respond to the parents' question about therapy alone, and what is the monitoring plan?
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Therapy alone is not sufficient for active psychosis with functional decline; antipsychotic treatment is indicated. However, psychosocial treatment is essential and additive: psychoeducation, cognitive behavioral therapy for psychosis (CBTp), family intervention, supported education/employment, and relapse planning.
Explain that antipsychotics reduce relapse risk and shorten the duration of untreated psychosis, which predicts outcome. Acknowledge the parents' concerns about side effects and present the monitoring plan as the safeguard.
Monitoring plan:
- Baseline: weight, BMI, waist circumference, BP, fasting glucose/HbA1c, lipids, prolactin (if risperidone), ECG if indicated, pregnancy test.
- Weeks 1–4: tolerability, EPS/akathisia, sedation, orthostasis; weight at each visit.
- 3 months and annually: metabolic panel; more often if abnormal.
- Suicide risk at each contact; safety plan with parents.
- Adherence: consider LAI aripiprazole given transportation limits; discuss with family.
Document shared decision-making and a relapse signature plan.