Overview
- Seasonal affective disorder is a recurrent form of depression linked to shorter days, typically returning in late fall and easing in spring or summer.
- Common symptoms include low mood, oversleeping, daytime fatigue, irritability, carbohydrate cravings, weight gain, and trouble concentrating.
- Bright-light therapy with a light box delivering roughly 5,000–10,000 lux is the standard treatment, usually used each morning for at least 30 minutes.
- Evidence shows substantial benefit, including about 64% symptom improvement in a 2015 study and meta-analytic support in 2024 for bright light as an adjunct in depression.
- Cognitive behavioral therapy and, in moderate or severe cases, antidepressants are effective options, with added benefit from morning sunlight, regular exercise, consistent sleep, and social connection.