The evolving science of pharmacogenetics: clinical and ethnic perspectives.

The field of pharmacogenetics has witnessed remarkable progress during the past several decades. Clinical observations of severe toxic reactions and findings of dramatic interindividual as well as cross-ethnic differences in response to therapeutic agents have been instrumental in fostering advances of the field. Research on cytochrome P450 isozymes may be of particular importance to the field of psychiatry, because most psychotropics depend on these enzymes for their biotransformation. This article traces the progress of research in this area and highlights the importance of clinical and cross-ethnic observations in providing the impetus and direction for the field. Knowledge derived from this line of research is likely to make important contributions toward establishment of rational guidelines for psychopharmacotherapy. In addition, research on these enzymes may also have profound implications in regard to the pathogenesis of a number of major disorders, including several types of commonly encountered cancers, as well as neuropsychiatric problems, including Parkinson's disease, tardive dyskinesia, addiction, and drug-induced neurotoxicity.