Light therapy lamps have many advantages over medication in treating seasonal affective disorder. Unlike medication, light therapy has few side effects if any. A bigger problem is that antidepressants can take several weeks to start working -- and when your depression is seasonal, that's several weeks you don't have!
Still, it's best if you consult your doctor before trying light therapy. Your doctor can tell you if there are any reasons why you shouldn't use a sun lamp. People with certain eye problems, for instance, cannot safely use bright lights.
If you have bipolar disorder, there's a good chance that your mood cycle is affected in part by the seasons. However, you're also at higher risk for triggering a manic episode by using light therapy. Folks with bipolar should consult their psychiatrist before using a light therapy lamp.
In rare cases, other people can become hypomanic or manic from light therapy. If you start to feel anxious, over-energized, talking too much and too fast, and find yourself cleaning the house at 3 a.m., talk to your doctor immediately.
For most people, however, light therapy is likely to have no side effects at all. Those that do experience side effects are usually bothered by sleep disturbances. These can be prevented easily enough: start your therapy gradually, at half an hour a day, then go to 45 minutes, and then an hour. If you have trouble sleeping after starting light therapy, move your therapy to an earlier time of day, or try shorter sessions. As for trouble waking up in the morning, you probably have that already -- so make sure you do a therapy session when you wake up. You'll find you have much more energy throughout the day.
Again, these are things you should discuss with your doctor before beginning light therapy. Depending on your symptoms and their severity, your doctor may recommend shorter or longer sessions. Your doctor may also recommend splitting your sessions between morning and afternoon. It depends on your individual biology, so there's no single answer that will work for everyone.
