Mayo Clinic Health Manager
Get free personalized health guidance for you and your family.
Get StartedCauses
By Mayo Clinic staffThe specific cause of seasonal affective disorder remains unknown. It's likely, as with many mental health conditions, that genetics, age and, perhaps most importantly, your body's natural chemical makeup all play a role in developing the condition. A few specific factors that may come into play include:
- Your biological clock (circadian rhythm). The reduced level of sunlight in fall and winter may disrupt your body's internal clock, which lets you know when you should sleep or be awake. This disruption of your circadian rhythm may lead to feelings of depression.
- Melatonin levels. The change in season can disrupt the balance of the natural hormone melatonin, which plays a role in sleep patterns and mood. Talk to your doctor to see whether taking melatonin supplements is a good option.
- Serotonin levels. A drop in serotonin, a brain chemical (neurotransmitter) that affects mood, might play a role in seasonal affective disorder. Reduced sunlight can cause a drop in serotonin, perhaps leading to depression.
- Saeed SA, et al. Seasonal affective disorder. http://www.uptodate.com/home/index.html. Accessed Aug. 28, 2009.
- Seasonal pattern specifier. In: Diagnostic and Statistical Manual of Mental Disorders DSM-IV-TR. 4th ed. Arlington, Va.: American Psychiatric Association; 2000. http://www.psychiatryonline.com. Accessed Oct. 31, 2009.
- Ravindran AV, et al. Complementary and alternative medicine treatments. Canadian Network for Mood and Anxiety Treatments (CANMAT) clinical guidelines for the management of major depressive disorder in adults. Journal of Affective Disorders. 2009;117:S54.
- Sarris J, et al. Kava and St. John's wort: Current evidence for use in mood and anxiety disorders. Journal of Alternative and Complementary Medicine. 2009;15:827.
- Hall-Flavin DK (expert opinion). Mayo Clinic, Rochester Minn. Oct. 31, 2009.