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Depression: Depression & Related Conditions

Shedding Light on Seasonal Affective Disorder

Carrie Steckl, Ph.D.

If you don't normally experience depression but find yourself feeling blue around the same time every year, you may want to be evaluated for Seasonal Affective Disorder (SAD).

sad woman outsideAs we move into fall and winter, the days get shorter and our exposure to sunshine diminishes. For some people, this is accompanied by sadness, lack of energy and motivation, and changes in sleep and appetite. Because these symptoms often show a pattern of starting in the fall, peaking in the winter, and dissolving in the spring, SAD was chosen as a term for this seasonal mental health issue.

Scientists aren't sure what causes SAD, though we know that less sunlight can alter circadian rhythms. This in turn can disrupt sleep, which can affect our mood, hormones, and the slew of neurotransmitters that course through the brain.

If you think you may experience SAD, I encourage you to talk to your primary care physician or a qualified mental health professional. He or she will conduct a thorough evaluation of your symptoms and will attempt to rule out other possible causes for your changes in mood and behavior.

According to the U.S. National Library of Medicine, here are a few more things we know about SAD:

  • It may begin during the teenage years or during adulthood.
  • Individuals who live in regions that experience long periods of darkness in the winter are at higher risk of developing SAD.
  • As with major depressive disorder and other forms of depression, both antidepressants and psychotherapy have been shown to be effective treatments.
  • Light therapy has been shown to be extremely effective in treating SAD. This entails using a special lamp that emits very bright light in such a way that emulates the sun. Treatment is started when seasons start to change and before symptoms normally appear. Your physician will provide instructions for using the light therapy box, but normally individuals sit a few feet away from it for 30 minutes a day (it is important to keep the eyes open but not look directly into the box). People who find relief from light therapy usually notice a difference in 3 - 4 weeks.

If light therapy interests you, be sure to seek this treatment from a qualified professional to ensure you are using the proper equipment. Simply sitting under a regular lamp won't do the trick; you also want to make sure you are using the treatment safely.


A.D.A.M. Medical Encyclopedia (March 8, 2013). Seasonal affective disorder. U.S. National Library of Medicine: