Long-term risperidone for pervasive developmental disorder: efficacy, tolerability, and discontinuation

To investigate the safety (e.g., weight gain, liver function, extrapyramidal side effects, and seizures) and efficacy of the long-term use of risperidone in children and adolescents and to ascertain the effects of drug withdrawal in a semi-naturalistic prospective, subjects with autism or pervasive developmental disorders not otherwise specified (PDDNOS) were treated with risperidone for 6 months after which parents were given the option of continuing for a further 6 months (final assessment at 12 months). Behavioral rating included Childhood Autism Rating Scale (CARS), Child Psychiatric Rating Scale (CPRS), Clinical Global Impression (CGI), and Child-Global Assessment Scale (C-GAS). Risperidone significantly ameliorated behavioral symptoms of PDD in 10 out of 11 subjects, with the effects on core symptoms being of smaller amplitude and of slower onset. No loss of effectiveness was observed in patients who continued risperidone for 12 months, while a relapse of associated behavioral symptoms occurred in the others. Weight gain was common, although the rate of increase lessened over a period of time; after drug withdrawal, considerable weight loss was observed in the patient who had previously shown the most significant increase. After 6 months of therapy, two patients developed facial dystonia: this disappeared after reducing dosage in one case, after drug discontinuation in the other. Amenorrhea was also observed, but no changes in liver function, blood tests or EEG were reported. The data indicate that risperidone is an effective and relatively safe drug for long term treatment of behavioral disruption in autistic children and adolescents.