A decision by US regulators to give the green light to Johnson & Johnson’s antipsychotic Risperdal as a treatment for schizophrenia in teenagers could cause a rumpus among groups concerned by the side effects of such drugs.

The US Food and Drug Administration has approved Risperdal (risperidone) for the treatment of schizophrenia in adolescents ages 13-17 and for the short-term treatment of bipolar mania associated with manic or mixed episodes of bipolar I disorder in children and adolescents ages 10-17. The approval is based on studies involving more than 430 adolescents and 160 children.

Risperdal is now the first FDA-approved atypical antipsychotic to treat either disorder in these age groups. A big earner for J&J, bringing in $1.1 billion in the second quarter, it is already approved for the treatment of schizophrenia and bipolar disorder in adults, and for irritability associated with autism in children aged 5-16.

Dianne Murphy, director of the FDA’s Office of Pediatric Therapeutics, said that these latest studies of Risperdal “provided an opportunity to assess the effectiveness, proper dose and safety of using this product in the paediatric population”. She added that the results “have provided an evidence-based approach for treating these disorders”.

The efficacy of Risperdal in the treatment of schizophrenia in adolescents was demonstrated in two short-term (six to eight weeks), double-blind, controlled trials. All patients were experiencing an acute episode of schizophrenia at the time of enrolment but after treatment generally had fewer symptoms, including a decrease in hallucinations and delusional thinking. The drug’s efficacy as a treatment of manic episodes in children or adolescents with bipolar I disorder was shown in a three-week trial and patients enjoyed a decrease in their elevated mood and hyperactivity.

Prescriptions of antipsychotics for teenagers have been written mostly ‘off-label’, but getting actual FDA approval means that J&J can start actively promoting Risperdal for the new indications. It gives the company a head-start over rival drugs, namely Eli Lilly’s Zyprexa (olanzapine) and Bristol-Myers Squibb/Otsuka Pharmaceutical’s Abilify (aripiprazole), which are being reviewed by the FDA for the treatment of paediatric patients.

However not everyone is happy about the decision and the FDA has admitted its concern about the safety profile of these drugs. However it feels that the benefits outweigh the risks and the agency will be keeping a close eye on post-marketing data.

The American Psychiatric Association said it “applauds the FDA for its review of scientific evidence that led to the approval of a new treatment for two severe psychiatric disorders in children” and its president Carolyn Robinowitz, said that “medications are an important part of a comprehensive treatment programme, which should include talk therapy and other interventions”.