The two most commonly used treatment modalities for depression are antidepressant medication and psychotherapy. However, only a minority of individuals with depression achieve remission with each type of treatment. On average, combination of antidepressants and psychotherapy achieves better results than either alone, but using two treatments at the same time may be wasteful and unnecessary. Several lines of evidence suggest that the apparently superior results of combination may be due to some individuals preferentially responding to antidepressants and others to psychological treatment. These findings point to the possibility that it may be possible to improve outcomes of depression by matching psychological and pharmacological treatment to individuals who are most likely to benefit from each one. The investigators propose to close this gap using a combination of clinical predictors and biomarkers to optimize the choice between psychological and pharmacological treatment.