A reader asks:

Somehow, I feel like it is always winter. I have never been able to wake up early in the morning even with the sun out. (Making classes in college was a disaster). I drag around for half the day, although I seem to recover by evening. I cannot control my weight with any diet. I try to make friends, but cannot keep them. I feel so isolated.

Answer:

Depression is a complex beast, and it can come with all kinds of patterns. Yours does look winter-like, and we know that for some people this symptom picture can last year round. There is a hint in what you say that light therapy could be effective for you regardless of the season. Your late waking indicates that your circadian rhythms are mal-synchronized with local clock time. This could be due to a genetic predisposition, but it also could be due to excessive light exposure in late evening – when you tend to feel better – because evening light can force the biological clock later, with resulting late awakening. For starters, make sure your indoor evening light is kept at a low comfort level that does not energize you. Whether the basic problem is genetic or environmental, morning light therapy could provide a solution by shifting your circadian rhythms earlier, just as it does for winter depression. You can expect to be able to wake up earlier, and there is good hope for an antidepressant effect. Indeed, a recent clinical trial at Columbia University Medical Center and Wesleyan University found that about half of patients with chronic, non-seasonal depression responded to light therapy just as well as SAD patients respond in winter. Definitely worth a try!