Long-term safety and efficacy of risperidone in children with disruptive behaviour disorders. Results of a 2-year extension study.

Objective: The aim of this study was to assess the longterm efficacy, safety, and tolerability of risperidone, over a cumulative period of 3 years, in treating children with disruptive behaviour disorders and below average intelligence (IQ 35-84).

Method: This trial included 35 children (aged 6-16 years), diagnosed with disruptive behaviour disorder. All subjects had previously completed a 1-year, open-label risperidone study, and this extension study followed them for an additional 2 years of treatment. Safety was assessed using the Extrapyramidal Symptom Rating Scale (ESRS), clinical laboratory tests, electrocardiograms, and the recording of adverse events, vital signs, Tanner score, and changes in body mass index (BMI). Efficacy was measured using the Clinical Global Impression of Severity (CGI-S) scale.

Results: The beneficial effects observed in the original trial were maintained during the extension. Few extrapyramidal side-effects occurred, as assessed by the ESRS, and there were no cases of tardive dyskinesia. The children showed a modest increase in BMI, part of which may be attributed to normal growth over the 2-year period. Most adverse events were mild or moderate in severity, and none of them were considered probably or very likely related to risperidone.

Conclusion: Continuing low-dose risperidone for up to 3 years appears to be safe and effective in children with disruptive behaviour disorders.