Risperidone-induced prolactin elevation in a prospective study of children, adolescents, and adults with mental retardation and pervasive developmental disorders.

Objective: Risperidone is widely prescribed for aggression and self-injury in children, adolescents, and adults with mental retardation (MR) and pervasive developmental disorders (PDD). Risperidone elevates prolactin more than other atypical antipsychotic medications. Females may show greater prolactin elevation than males.

Method: In this relatively long-term study of risperidone efficacy and safety for aggression and self-injury in children, adolescents, and adults with MR and PDDs, serum prolactin was measured in a 21-subject subset during the course of a double-blind, placebo-controlled trial. Prolactin was measured in ng/mL at baseline, once during acute treatment, and once during maintenance.

Results: In children and adolescents (n=10), mean age of 12.5 years, prolactin increased from mean 13.2+/-8.6 at baseline to 31.0+/-11.6 acutely and remained elevated at 37.9+/-10.4 in maintenance. In adults, mean age of 35.3 years, prolactin increased more markedly from 11.6+/-7.4 baseline (n=11) to 93.3+/-54.2 acutely but decreased to 67.8+/-62.9 in maintenance (n=7). Prolactin remained significantly elevated above normal in all subjects for at least 26 weeks. Mean prolactin of adult females, while similar to that of adult males at baseline, was 2.2 times male levels acutely and 3.7 times greater in maintenance.

Conclusion: In this small subset, mean prolactin elevation persisted for at least 26 weeks. In adults, females showed significantly greater elevations than males.