• major depressive disorder;
  • direct-to-consumer genetic testing;
  • psychiatric genetics;
  • gene–environment

Advances in technology have enabled research to link many genetic markers to specific disease risk. This has led to the commercialization of genetic tests across a wide range of medical disorders. Public interest in one's own future health and an increasing desire for autonomy over one's health care have facilitated a large and growing market for such genetic tests to be sold direct to the consumer (DTC). Amidst a plethora of tests for a broad range of medical conditions, DTC genetic tests currently include a number of tests related to risk for various psychiatric illnesses including major depressive disorder (MDD), bipolar disorder, schizophrenia, and obsessive-compulsive disorder and also for prediction of individual response to psychotropic medication. Although a large number of studies show that there is strong public interest in genetic susceptibility testing for psychiatric disorders, little is known about the impact on individuals of receiving the results of genetic tests. Moreover, the low predictive power and uncertain clinical validity and utility of DTC genetic tests for psychiatric disorders have led to both controversy and difficulties of interpretation of results. This review summarizes the rationale for using genetic risk tests in psychiatry, as an intervention for protective cognitive and behavioral change, and to predict medication response, with a focus on MDD. Since genetic risk information has the potential to influence major life-changing health decisions, there is an imperative to ensure that there is an appropriate evidence base to support the use of such genetic tests.