Transcultural psychopharmacology is a field that seeks to determine whether differences exist in the pharmacokinetic and pharmacodynamic handling of psychotherapeutic drugs among various ethnic groups and, where present, to determine the reasons for such variation. During the past two decades a number of studies have reported differences in the pharmacokinetics and pharmacodynamics of psychotropic medications among various ethnic groups. These variations appear to be mainly determined by genetic predisposition but can be influenced by other factors such as environment, psychosocial supports, and physicians' prescribing habits. Due to study design limitations, many questions regarding the transcultural aspects of psychotropic medications still remain unanswered. This critical review discusses the transcultural psychopharmacology of Asian versus non-Asian populations. It will also include data on tardive dyskinesia, discuss new developments, touch on the problems associated with present research in the area, and provide recommendations for designing future research studies.