What Is Seasonal Affective Disorder?
Seasonal Affective Disorder (SAD) is a type of depression linked to seasonal changes, most commonly occurring during the fall and winter months when daylight hours are shorter. It’s believed to result from a disruption in the body’s internal biological clock (circadian rhythm) and an imbalance in brain chemicals like serotonin and melatonin, which regulate mood and sleep. Reduced sunlight can lower serotonin levels—leading to sadness or fatigue—and increase melatonin production, which causes drowsiness and lethargy. People with SAD often notice their symptoms improving naturally during spring and summer when daylight exposure increases.
Common symptoms include persistent sadness, low energy, difficulty concentrating, changes in appetite (especially craving carbohydrates), oversleeping, and withdrawal from social activities. In more severe cases, it can resemble major depressive disorder, significantly affecting daily life. Light therapy, which involves exposure to bright artificial light, is a common treatment that helps reset circadian rhythms. Lifestyle changes—like spending time outdoors, exercising regularly, and maintaining a balanced diet—can also reduce symptoms. For those with more intense or recurring symptoms, psychotherapy and ongoing medical evaluation may be beneficial.
