This will be a prospective longitudinal cohort study of 2,420 consecutively enrolled patients who are prescribed an SSRI or SNRI (Citalopram [Celexa], Escitalopram [Lexapro], Fluoxetine [Prozac/Prozac Weekly], Fluvoxamine [Luvox], Paroxetine, [Paxil/Paxil-Cr], Sertraline [Zoloft], Venlafaxine [Effexor/Effexor XR], Duloxetine [Cymbalta]). Patients will be drawn from the practices of approximately 200 CAPTN participants in the United States and Canada.