Recognizing seasonal affective disorder

When the smell of wood smoke fills the air and night falls before dinner, rest assured that autumn has turned to winter. But somewhere between the backyard bonfires and sipping hot cocoa, a less pleasant phenomenon takes hold of some people: seasonal affective disorder, or SAD.

A yearly ordeal

"SAD is a significant mood disorder that changes people's capacity to work, or enjoy family or friends, and we think it's related to the light/dark cycles," says Mark Frye, M.D., chair of Psychiatry and Psychology at Mayo Clinic in Rochester.

While many people struggle with cabin fever during a long winter, SAD symptoms can be severe and functionally disabling. Dr. Frye says SAD is much like bipolar disorder, or major depression, but specifically related to the change of seasons.

SAD symptoms

Most SAD symptoms start in the fall and continue through the winter months, sapping your energy and making you feel moody. But don't brush off that yearly feeling as simply a case of the winter blues or a seasonal funk that you have to tough out on your own.

Although winter symptoms usually go away once spring or summer hits, some people experience the opposite pattern. In either case, symptoms may start out mild and become more severe as the season progresses.

Symptoms specific to winter-onset SAD, sometimes called winter depression, may include:

• Oversleeping or hypersomnia
• Appetite changes, especially a craving for foods high in carbohydrates
• Weight gain
• Depressed mood
• Irritability
• Tiredness or low energy
• Problems getting along with other people
• Heavy feeling in the arms or legs

SAD causes

While specific causes of SAD remain unknown, factors that may come into play include:

• Your biological clock or circadian rhythm
  Reduced sunlight in fall and winter may disrupt your body's internal clock and lead to feelings of depression.
• Serotonin levels
  Reduced sunlight can cause a drop in serotonin — a brain chemical that affects mood — and can 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.

Support and treatment

It's normal to have some days when you feel down. But if you feel down for days at a time and you can't get motivated to do activities you normally enjoy, see your doctor. Treatment can help prevent complications, especially if SAD is diagnosed and treated before symptoms become severe.

Treatment for SAD may include light therapy (phototherapy), psychotherapy and medications. Dr. Frye says providers often will prescribe light boxes, and there is one antidepressant available — Wellbutrin — that can prevent SAD.

By Mayo Clinic Health System staff