Genotyping, especially for drug metabolizing enzymes, could enable more rational, cost-effective and optimal prescribing in future psychopharmacotherapy. Although the advances of pharmacogenetics may have many benefits in clinical practice, the importance of non-genetic factors must also be considered as cultural and environmental factors significantly impinge on response to medications. To clarify the extent pharmacogenetics can be adopted in clinical practice to predict drug response in patients from diverse backgrounds, further studies in different ethnic groups and clinical settings are required.