Seasonal Affective Disorder
Seasonal Affective Disorder (SAD) is a type of depression that occurs at certain times of the year, often in the fall and winter months. It is believed to be related to changes in light exposure and can impact mood and energy levels. People may experience feelings of sadness and fatigue during these seasons, which can vary in intensity.
Mental & Behavioral- What exactly is seasonal affective disorder?MedlinePlusMay 2026
Seasonal affective disorder (SAD) is a type of depression that comes and goes with the seasons, usually starting in late fall and early winter and going away in spring and summer. It makes you feel sad, hopeless, and tired during those darker months.
- Why do I feel so sad during the winter months?MedlinePlusMay 2026
During winter, there's less sunlight, which can throw off chemicals in your brain that control your mood. Your body may also make too much of a sleep hormone called melatonin and not enough vitamin D, which can make you feel down.
- How does SAD differ from regular depression?MedlinePlusMay 2026
SAD is depression that follows a seasonal pattern—it comes back at the same time each year, usually in fall and winter. Regular depression can happen anytime and doesn't follow the seasons.
- Can SAD happen in spring or summer too?MedlinePlusMay 2026
Yes, some people do get SAD in spring or summer, but this is much less common than the fall and winter type.
- Am I more likely to get SAD because of where I live?MedlinePlusMay 2026
Yes, you're more likely to get SAD if you live far from the equator where there's less daylight in winter. People who live closer to the poles experience longer, darker winters.