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As the winter approaches and the days get shorter, some people experience a form of depression called Seasonal Affective Disorder (SAD)—an extreme case of the winter blues that is relieved during the spring and summer months.

Although SAD isn't totally understood, it is a real illness with sometimes severe symptoms. As seasons change, there is a shift in our biological internal clocks or circadian rhythms, partly in response to the changes in sunlight patterns. This can cause our biological clocks to fall out of step with our daily schedules. For people with SAD, their bodies have a difficult time adjusting to the shortage of sunlight in the winter months. SAD symptoms are most pronounced in January and February, when the days are shortest.

What are the symptoms?

  • Symptoms of depression occur regularly during the fall or winter months (changes in sleeping and eating habits; persistent sad, anxious or "empty" mood; loss of pleasure in activities once enjoyed).
  • Depression subsides in the spring and summer months.
  • Symptoms have occurred in the past two years, with no non-seasonal depression episodes.
  • Seasonal episodes substantially outnumber non-seasonal depression episodes.
  • The individual craves sugary or starchy foods.

Who gets SAD?

Young people and women are at the highest risk for the disorder, but it can affect anyone. In fact, an estimated 25 percent of the population suffers from mild winter SAD, and about 5 percent suffer from a more severe form of the disorder.

What causes SAD?

Melatonin, a sleep-related hormone secreted by the pineal gland in the brain, has been linked to SAD.This hormone is believed to cause symptoms of depression and is produced at increased levels in the dark. So when the days are shorter and darker, the production of this hormone increases.

Is treatment available?

Yes. People don't need to wait for the spring months to overcome SAD. For mild symptoms, spending time outdoors during the day or arranging homes and workplaces to receive more sunlight may be helpful. Regular exercise particularly if done outdoors may help because exercise can relieve depression. One study found that an hour's walk in winter sunlight was as effective as two and a half hours under bright artificial light.
For more severe symptoms, a light treatment called phototherapy might help. Phototherapy has been shown to suppress the brains secretion of melatonin. Although research hasn’t proven that this treatment has an antidepressant effect, it has helped many people. The device most often used today is a light box that emits very bright light through a filter. SAD patients sit in front of the light box for a few minutes everyday while they work or do other activities. If phototherapy doesn’t work, an antidepressant drug may help reduce or eliminate SAD symptoms, but there may be unwanted side effects to consider.

In all cases, people who think they may have SAD should discuss their symptoms with a doctor, EAP or mental health professional.

From the National Mental Health Association
Mental Health Resource Center

© 2001 National Mental Health Association