It has been estimated that about half of all depression is seasonally triggered. This is true for both regular depression (also referred to as unipolar depression) as well as bipolar depression (bipolar disorder). After a month or so of diminished sunlight (or by about mid-December), many people prone to SAD start to experience symptoms. It may start as changes in sleep, appetite, concentration, and memory, diminished libido, and a loss of interest in things. In the case of bipolar disorder, the diminished hours of daylight can trigger either depression symptoms, or manic ones (feeling of euphoria, expansive ideas, unusual creativity, diminished need for sleep, and increased energy. There may also be an increase in libido, a tendency to talk too fast, and spending a lot of money in a short period of time - unrelated to the shopping one might do for the holidays).
If you suspect that you might have SAD, see a qualified mental health practitioner. In the Chicago area, see us at www.heritageprofessional.com. Treatment can include exposure to full spectrum light, of 10,000 lumens (or lux) for at least 30 minutes per day. It may also involve the use of counseling and prescription medication.
