major depressive disorde
"I started taking Effexor at age 19 after about 2 1/2 years on Prozac. The reason for the switch was that I developed anxiety problems at that age in addition to depression, and the Prozac was not treating the anxiety. Effexor works very well to treat both anxiety and depression but if I stop taking it for even 1-2 days (which is often because I am very forgetful) I become extremely depressed for the next 1-2 days. Right now I am in one such down swing after taking my Effexor for the first time in about 5 days. If you avoid doing that though you should be fine, the medication does help a lot."