The specific cause of seasonal affective disorder remains unknown. Some factors that may come into play include:
Sept. 12, 2014
- Your biological clock (circadian rhythm). The reduced level of sunlight in fall and winter may cause winter-onset SAD. This decrease in sunlight may disrupt your body's internal clock and lead to feelings of depression.
- Serotonin levels. A drop in serotonin, a brain chemical (neurotransmitter) that affects mood, might play a role in SAD. Reduced sunlight can cause a drop in serotonin that may trigger depression.
- Melatonin levels. The change in season can disrupt the balance of the body's level of melatonin, which plays a role in sleep patterns and mood.
- Saeed SA, et al. Seasonal affective disorder. http://www.uptodate.com/home. Accessed Aug. 13, 2014.
- Specifiers for depressive disorders: With seasonal pattern. In: Diagnostic and Statistical Manual of Mental Disorders DSM-5. 5th ed. Arlington, Va.: American Psychiatric Association; 2013. http://www.psychiatryonline.org. Accessed Aug. 13, 2014.
- Seasonal affective disorder. National Alliance on Mental Illness. http://www.nami.org/Template.cfm?Section=By_Illness&Template=/ContentManagement/ContentDisplay.cfm&ContentID=23051. Accessed Aug. 13, 2014.
- Seasonal-affective disorder. American Psychiatric Association. http://www.psychiatry.org/seasonal-affective-disorder. Accessed Aug. 13, 2014.
- Varteresian T, et al. Natural products and supplements for geriatric depression and cognitive disorders: An evaluation of the research. Current Psychiatry Reports. 2014;16:456.
- Sanassi LA. Seasonal affective disorder: Is there light at the end of the tunnel? Journal of the American Academy of Physician Assistants. 2014;27:18.
- Melatonin. Natural Medicines Comprehensive Database. http://www.naturaldatabase. Accessed Aug. 13, 2014.
- Depression. National Institute of Mental Health. https://www.nimh.nih.gov/health/publications/depression/index.shtml. Accessed Aug. 13, 2014.
- Ravindran AV, et al. Complementary and alternative therapies as add-on to pharmacotherapy for mood and anxiety disorders: A systematic review. Journal of Affective Disorders. 2013;150:707.
- Stress and relaxation techniques. NCCAM Clinical Digest. http://nccam.nih.gov/health/providers/digest/relaxation.htm. Accessed Aug. 13, 2014.
- Massage therapy for health purposes. NCCAM Clinical Digest. http://nccam.nih.gov/health/providers/digest/massage. Accessed Aug. 13, 2014.
- Kung S (expert opinion). Mayo Clinic, Rochester, Minn. Aug. 29, 2014.