AbstractOptimal treatment for patients with mental health illness depends upon accurate diagnosis, individualized treatment, patient adherence to effective agents, and an intact family support system. Healthcare system (eg, limited access to certain medications), provider (eg, bias and discrimination), and patient factors (eg, biologic and cultural) greatly influence the level of mental health care given, especially to minority populations. Furthermore, limited data in African Americans, Hispanics, and Asians suggest that there are racial, ethnic, and cultural variations in responsiveness to antipsychotic medications, as well as potential differences in the types, rates, and severity of adverse events. Non-Caucasian patients tend to receive older, less-expensive agents, sometimes at higher doses (African Americans, leading to potentially intolerable side effects and early withdrawal of therapy or a less than optimal therapeutic response, respectively. Differences in response may have a biologic, pharmacokinetic, or pharmacodynamic basis and may also be influenced by lifestyle factors (eg, diet, smoking). Variations in dopamine receptor occupancy and cytochrome P450 polymorphism may explain some racial/ethnic differences in antipsychotic effects and adverse-event profiles, suggesting that dosing may need to be individualized based on ethnicity. The newer atypical antipsychotics, while seemingly better tolerated compared with conventional antipsychotics, may not be totally devoid of bothersome side effects (eg, extrapyramidal side effects) in minorities. While further research is needed, recognition of potential interracial/ethnic pharmacogenetic differences may help minimize intolerable side effects and achieve optimal psychosis management.