My depressive episodes generally, historically, last about 3 months also. Generally not too much longer. I'm starting to see them last not quite as long (more like a month to 6 weeks now which is a huge improvement) as I've learned much better and healthier coping mechanisms, I communicate my need for help to my therapist and pdoc much earlier on, and we finally have a pretty good handle on what meds work for whatever symptoms I'm having.