Antidepressants -- the SSRIs (Prozac, Zoloft, Celexa, Lexapro, etc), the SSRI/SNRI combos (Effexor and Cymbalta), the tricyclics (Amitriptyline, Nortriptyline, etc) and Wellbutrin (although it does a better job with depression than anxiety).
What triggered his initial depression?