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Seasonal Depression (Seasonal Affective Disorder)

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Do the winter months get you down more than you think they should? If so, you might have seasonal depression, also known as seasonal affective disorder (SAD).

Seasonal depression is a mood disorder that happens every year at the same time. A rare form of seasonal depression, known as "summer depression," begins in late spring or early summer and ends in fall. In general, though, seasonal affective disorder starts in fall or winter and ends in spring or early summer.

What Causes Seasonal Affective Disorder?

While we don't know the exact causes of SAD, some scientists think that certain hormones made deep in the brain trigger attitude-related changes at certain times of year. Experts believe that SAD may be related to these hormonal changes. One theory is that less sunlight during fall and winter leads to the brain making less serotonin, a chemical linked to brain pathways that regulate mood. When nerve cell pathways in the brain that regulate mood don't function normally, the result can be feelings of depression, along with symptoms of fatigue and weight gain.

SAD usually starts in young adulthood and is more common in women than men. Some people with SAD have mild symptoms and feel out of sorts or irritable. Others have worse symptoms that interfere with relationships and work.

Because the lack of enough daylight during wintertime is related to SAD, it's seldom found in countries where there's plenty of sunshine year-round.

What Are the Symptoms of SAD During Winter?

People with SAD have many of the normal warning signs of depression, including:

  • Less energy
  • Trouble concentrating
  • Fatigue
  • Greater appetite
  • Increased desire to be alone
  • Greater need for sleep
  • Weight gain

What Are the Symptoms of SAD During Summer?

  • Less appetite
  • Trouble sleeping
  • Weight loss

How Is SAD Diagnosed?

If you've been feeling depressed and have some of the above symptoms, see your doctor for an assessment. He or she will recommend the right form of treatment for you.

How Is Seasonal Depression Treated?

There are different treatments,  depending on the severity of your symptoms. Also, if you have another type of depression or bipolar disorder, the treatment may be different.

Many doctors recommend that people with SAD get outside early in the morning to get more natural light. If this is impossible because of the dark winter months, antidepressant medications or light therapy (phototherapy) may help.

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