Objective: To describe tolerability and efficacy of risperidone in very young children with pervasive developmental disorders.
Method: Twenty-four children aged 3.6 to 6.6 years (mean 4.6 years +/- 8 months) enrolled during 1999 and 2000 participated in a 16-week open-label trial with risperidone monotherapy. Outcome measures included the Children's Psychiatric Rating Scale (CPRS), Childhood Autism Rating Scale (CARS), Clinical Global Impression-Improvement (CGI-I), and Children's Global Assessment Scale (C-GAS).
Results: Two subjects did not complete the trial because of side effects. The optimal dose was 0.5 mg/day. After the treatment a 21% improvement in CPRS and a 14% improvement in CARS total scores was found. Items related to behavioral control (hyperactivity, fidgetiness, rhythmic motions) and affect regulation (lability of affect, angry affect) improved more than 25%. Based on improvement of at least 25% on the CPRS and a score of 1 or 2 on the CGI-I, eight subjects were considered responders. Functional impairment (C-GAS) improved more than 25%. Thirteen subjects (54%) were free of any side effects; in the other participants risperidone was well tolerated. Only three subjects had a weight gain greater than 10%.
Conclusions: Low-dose risperidone may positively affect symptoms in young autistic children, improving disruptive/hyperactive behavior and affective dysregulation. Further controlled studies in this age group are warranted.