Purpose of review Pharmacogenetic studies on responses to antipsychotic drugs may lead to the identification of biological predictors of drug efficacy and a better understanding of the molecular underpinnings of antipsychotic drug action. The present review discusses early studies of antipsychotic drug response and highlights ongoing work in this rapidly developing area. Recent findings Recently conducted studies have expanded prior work on clozapine to the consideration of newer atypical antipsychotic agents. Studies of genetic variation in the dopamine D2 receptor and the serotonin (5-hydroxytryptamine) 2A receptor are the most promising in terms of prediction of clinical efficacy. Moreover, studies of antipsychotic drug-induced side-effects such as tardive dyskinesia and weight gain also point to variation in dopamine and serotonin receptor genes. New study designs that incorporate first-episode drug-naive subjects may be especially informative for future work on pharmacogenetics. Summary The rapidly growing body of genomic information and the new study designs that incorporate pharmacogenetic strategies may provide the data necessary to begin to unravel the complex phenotype of response to antipsychotic drugs. Future studies will focus on more comprehensive genomic analyses as well as sample sizes that are significantly larger than currently available datasets.