Major depressive disorder is a debilitating disease that imposes significant social and economic burdens due to its 10% life-time prevalence and 15% association with suicide, and so urgent measures are needed. However, not all individuals benefit from antidepressant treatment, and some patients poorly respond or develop side effects. It would be helpful to identify a biomarker that could indicate the best therapeutic tool that is likely to be effective and tolerable for each patient. In this context, a marked effort has been directed toward the search for genetic predictors of drug efficacy in mood disorders over the last few years. However, the present evidence from pharmacogenomic studies does not match those expectations. So, how far is "personalized medicine" for depression from clinical use? It is important to translate the results of such pharmacogenomic studies to better treatment in clinical practice. Here, I provide an overview of pharmacogenomic research results with both a genome-wide approach and candidate approach, and suggest possible ways to apply pharmacogenomic results in clinical settings.
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