For some it starts in the spring and summer and goes away in the fall or winter, but that’s very rare.
The cause of the disorder is not known, but researchers say those who have the disorder are found to have an imbalance of serotonin, which affects mood, and not enough vitamin D, which comes from sunlight, among other places. They also have too much melatonin, which regulates sleep, according to the NIH.
What are the symptoms?
Symptoms may include feeling sad, irritable, hopeless or worthless, having low energy, difficulty eating or sleeping, a gloomy outlook, losing interest in activities you used to enjoy and thoughts of death or suicide. According to the Mayo Clinic, symptoms specific to winter-onset SAD include oversleeping, wright gain and appetite changes, particularly craving high-carb foods. Symptoms specific to summer-onset SAD include insomnia, agitation or anxiety, loss of appetite and weight loss.
People with those symptoms and who feel depressed for days at a time should see their doctor.
Who does SAD affect?
Anyone can be affected by SAD, but it is more common in women, young people, and people who live far from the equator, in areas where there is less sunlight throughout the day. People who have bipolar disorder or major depression, as well as those with blood relatives with SAD or other forms of depression, are more likely to be at risk of the disorder.
How can it be treated?
Light therapy is typically the main treatment for SAD. According to the National Institute of Mental Health, other treatments include medication, such as selective serotonin reuptake inhibitors, and psychotherapy.