Seasonal affective disorder is a type of depression – Major Depressive Disorder with Seasonal Pattern. The symptoms usually occur during the autumn and winter months (when there is less sunlight) and usually improve with the arrival of spring.
SAD is more than just “winter blues.” The symptoms can be distressing and overwhelming and can interfere with daily functioning. It is more common among women than men, and may begin at any age, but it typically starts when a person is between ages 18 and 30.
Research suggests that SAD has been linked to a biochemical imbalance in the brain prompted by shorter daylight hours and less sunlight in winter. As seasons change, people experience a shift in their biological internal clock or circadian rhythm that can cause them to be out of step with their daily schedule. SAD is more common in people living far from the equator where there are fewer daylight hours in the winter.
Symptoms and Diagnosis
Common symptoms of SAD include fatigue, even with too much sleep, and weight gain associated with overeating and carbohydrate cravings. SAD symptoms can vary from mild to severe and can include many symptoms similar to major depression, such as:
- Feeling sad or having a depressed mood
- Loss of interest or pleasure in activities once enjoyed
- Changes in appetite; usually eating more, craving carbohydrates
- Change in sleep; usually sleeping too much
- Loss of energy or increased fatigue despite increased sleep hours
- Increase in purposeless physical activity (e.g., inability to sit still, pacing, handwringing) or slowed movements or speech (these actions must be severe enough to be observable to others)
- Feeling worthless or guilty
- Difficulty thinking, concentrating, or making decisions
- Thoughts of death or suicide
SAD can be effectively treated in several ways, including light therapy, antidepressant medications, talk therapy or some combination of these. While symptoms will generally improve on their own with the change of season, symptoms can improve more quickly with treatment.