Atypical antipsychotics in persons with developmental disabilities

The introduction of clozapine spawned the development of several novel antipsychotic agents during the last decade. Compared to traditional agents, these "atypical antipsychotics" demonstrate more favorable characteristics in terms of efficacy and medication-associated abnormal involuntary movements. Several underlying neurochemical mechanisms have been posited for the differences noted between traditional and atypical antipsychotic drugs. Most theories have been based on the observation that atypical agents have higher affinities and greater selectivity for different dopamine receptor subtypes and for serotonin receptors. In addition, there is speculation about the involvement of other types of neurotransmitters (e.g., gamma-aminobutyric acid, N-methyl-D-aspartate) in the actions of these drugs. A review of the current literature on the developmental disabilities indicated that the study populations can be divided into three general categories: (a) individuals with mental retardation and a psychiatric syndrome; (b) individuals with mental retardation and behavioral problems; and (c) individuals with autism and other pervasive developmental disorders. The atypical antipsychotics most consistently appeared to reduce symptoms of self-injury, aggression, agitation, and repetitive behaviors. It is not yet clear whether they enhance prosocial behavior, although findings of some reports suggested this. A clear limitation of the available evidence is that few studies are methodologically sound. Suggestions for further research are offered. (C) 1999 Wiley-Liss, Inc.