These experiences are a set of real medical symptoms called Seasonal Affective Disorder (SAD). SAD generally lasts several months and then disappears when the sun shines longer and more brightly in the sky. In its full form, SAD negatively impacts productivity at work, school and home - and even in social relationships. In milder forms, SAD can cause irritability and moodiness.
Statistics on SAD
- Seasonal Affective Disorder (SAD) is a pattern of significant depressive symptoms that occur and then disappear with the changing of the seasons. SAD is sometimes called "Winter Depression" or "Winter Blues".
- SAD affects millions worldwide, primarily occurring in areas of higher latitudes from the equator.
- SAD affects women and children more than men.
- Awareness of this mental condition has existed for more than 150 years, but it was only recognized as a disorder in the early 1980s. Diagnosis for SAD is Major Depressive Disorder with a seasonal pattern.
- Symptoms include many of the same symptoms of depression: sadness, anxiety, lost interest in usual activities, withdrawal from social activities and an inability to concentrate. The difference though, is that these symptoms resolve each spring and tend to occur again in late fall.
- Individuals with SAD report sleeping an average of 2.5 hours more in winter than in the summer. The general population sleeps 0.7 hours more in the winter.
- Melatonin, a sleep-related hormone secreted by the pineal gland in the brain, has been linked to SAD. This hormone, which may cause symptoms of depression, is produced at increased levels in the dark. Therefore, when the days are shorter and darker the production of this hormone increases.