Seasonal affective disorder (SAD) is a type of depression that occurs at a specific time of the year, usually during the winter months when there is less sunlight. It is also known as seasonal depression or winter depression. SAD is considered a subtype of major depressive disorder.

People with seasonal affective disorder experience symptoms of depression that are related to the changing seasons. Common symptoms include:

1. Persistent feelings of sadness, hopelessness, or emptiness
2. Loss of interest or pleasure in activities once enjoyed
3. Changes in appetite, particularly craving for carbohydrates
4. Weight gain
5. Fatigue or low energy
6. Difficulty concentrating or making decisions
7. Increased sleep or excessive sleepiness
8. Social withdrawal or isolation
9. Irritability or agitation

The exact cause of seasonal affective disorder is unknown, but it is believed to be related to reduced exposure to sunlight during the winter months. The decrease in sunlight can disrupt the body’s internal clock and affect serotonin levels, a neurotransmitter that affects mood. Treatment for seasonal affective disorder may include light therapy, where individuals are exposed to bright light to mimic natural sunlight. Antidepressant medication and psychotherapy, such as cognitive-behavioral therapy, may also be recommended. It is important to consult a healthcare provider or mental health professional for an accurate diagnosis and appropriate treatment plan.