Seasonal Affective Disorder

Seasonal affective disorder (SAD) is more than just the “blues”.  Affecting up to 5% of adults in the United States, it can last as much as 40 percent of the year.  SAD can cause significant impairment of normal daily activity, and can lead to deeper complications if left unaddressed.

The symptoms of SAD overlap with those of major depression, but tend to occur during the winter months.  There are also some people who suffer from seasonal depression in the spring and summer months, but the majority experience SAD when the available sunlight is less. [In San Francisco some people with winter SAD will have a period of increased symptoms in July or August when the fog is particularly bad].

Symptoms may include:

  • Feeling sad or depressed most of the day, almost every day.
  • Loss of interest in previously engaging activities.
  • Difficulty sleeping, or too much sleep – the typical SAD pattern is long periods of poor quality sleep.
  • Fatigue that cannot be explained by work or activity.
  • Changes in appetite or unexplained weight gain or loss – they typical winter SAD pattern is increased appetite and particularly carbohydrate craving.
  • Feeling guilty, hopeless or worthless.
  • Suicidal thoughts.

Seasonal changes may also have an effect on people with bipolar, some may experience a “down” mood in the autumn and mild hypomania in the spring as daylight begins to lengthen.


Sunlight, or artificial sunlight is often the key to treatment of SAD.  Many people get help using light therapy, such as a light box or full-spectrum lamps, and it can also be helpful to try to find ways to maximize outdoor time whenever possible, by parking further away from the store or office, for example, to allow a bit more walking time under the sky.

Cognitive behavior therapy has been found helpful by many people, and, in severe cases, medication may be prescribed.  Consult your physician or other medical practitioner if you are experiencing these symptoms, it is not something that you can “snap out” of, don’t be afraid of asking for help.

For More Information:

Moodsurfing has written a lot about seasonal changes in mood and sleep. Here are just a few articles…

Using a Therapy Light – in which we talk about the overlap between hibernation and SAD.

Seasonal Affective Disorder – Fall Reminder

Luminette Light Therapy Glasses

Bipolar Depression Light Therapy


Seasonal Affective Disorder.  American Psychiatric Association: