Current applications of clinical genetic testing for psychiatric practice.

Pharmacogenetic testing allows physicians to identify patients who are likely to have adverse reactions to certain medications because they metabolize them poorly or too rapidly. Much research has focused on the gene P-450 2D6, which has been shown to affect patients' response to various drugs including antidepressants and antipsychotics. Patients with certain genotypes may experience negative side effects from medications or may see no benefit at all. This article describes the first pharmacogenetic test to be widely used, which identifies variation in the P-450 2D6 gene, and the patient populations that would benefit from it.