Can a Teenager Take Clozapine? What the Evidence Shows in Children and Adolescents

Creator: Ryan S. Sultan, MD
Published: 2026-11-12

By Ryan S. Sultan, MD
Psychiatrist · Columbia University Irving Medical Center
Published November 12, 2026 · 5-minute read

A teenager can be prescribed clozapine, and the prescription is off-label. The pediatric section of the prescribing information is one sentence: "Safety and effectiveness in pediatric patients have not been established."¹ Guidelines summarized in a 2014 systematic review recommend clozapine for young people with early-onset schizophrenia who haven't responded to two adequate trials of different antipsychotics.²

Three double-blind trials enrolled 21, 25, and 39 young people, and the longest ran 12 weeks.^{3, 4, 5}

Why the question comes up before age 18

Approximately 8% of patients with schizophrenia are diagnosed before age 18, and 18% have their first symptoms before 18. Early age of onset is a consistent risk factor for treatment-resistant schizophrenia.⁶ The criteria for treatment resistance are on the page about when to start clozapine.

What three randomized trials found

Three double-blind trials of clozapine in children and adolescents with schizophrenia
Trial	Design and result
Kumra 1996, clozapine vs haloperidol	21 patients, mean age 14.0, with onset by age 12 and no response to older antipsychotics. Over 6 weeks, clozapine was superior to haloperidol on all measures of psychosis. Neutropenia and seizures were major concerns, and one third of the group had stopped clozapine at the time of the report
Shaw 2006, clozapine vs olanzapine	25 patients aged 7 to 16 whose illness had resisted at least 2 antipsychotics. Over 8 weeks the differences favored clozapine and reached significance only for negative symptoms (P = .04; effect size 0.89)
Kumra 2008, clozapine vs olanzapine up to 30 mg/day	39 patients aged 10 to 18, resistant or intolerant to at least two antipsychotics. Over 12 weeks, 66% on clozapine met response criteria compared with 33% on olanzapine

Sources: the three published trial reports.^{3, 4, 5}

The Shaw trial's authors wrote that the study did not definitively demonstrate the superiority of clozapine, and that a more favorable clinical response was balanced against more adverse events.⁴

In the 2008 trial's open-label extension, 7 of 10 young patients (70%) who had failed high-dose olanzapine responded to 12 weeks of clozapine.⁷

A 2018 network meta-analysis of 28 randomized trials with 3,003 participants found clozapine significantly more effective than all other antipsychotics analyzed. The authors noted that most comparisons were based on one study or on indirect evidence.⁸

Neutropenia is common in young patients, and most continue clozapine

One series followed 172 patients who started clozapine at a mean age of 15, for a median of 8 months. Neutropenia, defined as an absolute neutrophil count below 1,500, developed in 23 patients (13%). Agranulocytosis developed in one (0.6%). Eleven of the 24 affected patients were successfully restarted on clozapine, and 8 of 172 (5%) eventually stopped it because of a blood count problem.⁹

The authors concluded that the incidence of agranulocytosis doesn't appear higher than in the adult literature.⁹

A National Institute of Mental Health chart review covered 87 hospitalized children and adolescents whose psychosis began before age 13. Moderate neutropenia occurred in 17 (20%), with no cases of agranulocytosis or severe infection. Sixteen of those 17 were successfully treated with clozapine by discharge.¹⁰

The authors described these neutropenia rates as considerably higher than in adults. Younger age, African American ethnicity, and male gender were risk factors, and they are also risk factors for benign neutropenia in healthy children and adolescents.¹⁰

The monitoring schedule is on the page about clozapine blood tests.

Weight, lipids, and glucose change within months

In the 2008 trial, both clozapine and olanzapine were associated with significant weight gain and related metabolic abnormalities.⁵ After 24 weeks of clozapine, 10 of 14 clozapine-treated patients (71%) had fasting triglycerides above 125 mg/dL, and 4 of 14 (29%) had a fasting glucose of 100 or higher.⁷

In the Shaw study, 15 patients were taking clozapine at the 2-year follow-up with sustained improvement. Lipid abnormalities had emerged in 6 and seizures in 1.⁴ The network meta-analysis found the highest weight gain with clozapine, quetiapine, and olanzapine.⁸

Other side effects in adolescents

A 2014 systematic review reported sedation and hypersalivation in over 90% of young patients. Seizures were uncommon, at under 3%, and new-onset diabetes was reported in under 6%.² A 2022 review of 18 studies reported constipation in 13% to 50% and no fatalities.¹¹

In 54 children and adolescents treated in double-blind or open-label clozapine trials, the rate of side effects was higher than typically found in adults and didn't appear related to dose or plasma concentration.¹² The clozapine side effects page covers each of these.

Limitations of the evidence

This evidence has limitations. First, the three randomized trials described here were small, and none of them ran longer than 12 weeks. Second, the long-term and side-effect data come from open-label follow-up, chart reviews, and reviews that pooled studies of different designs. Nevertheless, the 2014 review concluded that clozapine is effective and generally safe in refractory early-onset schizophrenia provided patients are regularly monitored.²

Starting it is a decision made with the child's psychiatrist, with blood counts, weight, lipids, and glucose followed closely.

Frequently asked questions

Can a teenager take clozapine?

A psychiatrist can prescribe it, as an off-label use. Guidelines summarized in a 2014 systematic review recommend clozapine for young people with early-onset schizophrenia who haven't responded to two adequate trials of different antipsychotics. The decision is made with the child's psychiatrist.²

Is clozapine approved for children?

No. The prescribing information states that safety and effectiveness in pediatric patients have not been established. Use under 18 is off-label.¹

Does clozapine work better than olanzapine in adolescents?

In a 12-week trial of 39 adolescents, 66% on clozapine met response criteria compared with 33% on high-dose olanzapine. An earlier trial of 25 patients did not definitively demonstrate the superiority of clozapine.^{5, 4}

Does clozapine cause low white blood cells more often in kids?

Neutropenia developed in 13% of 172 young patients in one series and agranulocytosis in 0.6%. Its authors concluded that the incidence of agranulocytosis doesn't appear higher than in the adult literature. The authors of a second chart review, of 87 inpatients, described neutropenia rates as considerably higher than in adults.^{9, 10}

What are the side effects of clozapine in adolescents?

A 2014 systematic review reported sedation and hypersalivation in over 90% of young patients, seizures in under 3%, and new-onset diabetes in under 6%. In a 12-week trial, both clozapine and olanzapine were associated with significant weight gain and related metabolic abnormalities.^{2, 5}

In a crisis: call or text 988, or go to the nearest emergency department. A first episode of psychosis belongs in a hospital-based or coordinated specialty care program.

I start and manage clozapine in an outpatient practice in Chelsea, Manhattan. Details are on the schizophrenia care in NYC page. Clozapine should not be stopped, skipped, or restarted without the prescriber. This page is general information and does not replace an evaluation.