This is just my personal opinion, but I really don't believe in the SAD theory for many people who show signs of depression in the fall to winter months. I think some of the pdocs out there just slap this on as an easy dx. My pdoc used to say that for me, but what about all of the other months when I was in hospital living with depression? I was no more depressed in the fall to winter than I was for the rest of the year.