Winter depression, also known as seasonal depression, is a type of affective disorder. Patients become depressed and have a significant loss of energy in winter; once the snow melts and the earth warms up, these symptoms disappear on their own and mood and energy return to normal. Seasonal depression is generally not taken seriously, but it is not to be underestimated as a painless seasonal mood disorder, and incomplete statistics show that 40% of patients have had suicidal thoughts due to extreme depression. According to modern medical research, the main cause of seasonal depression is that the human biological clock does not adapt to the shortened sunlight in winter, resulting in disruption of physiological rhythms and endocrine disorders, and disruption of emotional and mental states. The incidence of the disease is 2-4 times higher in women than in men. It can manifest itself as unhappiness, feeling that life is not fun, loss of vitality, lethargy, apathy; increased sleep, difficulty getting up in the morning; inability to finish work on time, failure to complete tasks that are usually easy; may have increased appetite, weight gain; always avoidance, dislike of contact with people; irritability, high temper; loss of libido; suicidal thoughts or feeling of no future. To stay away from winter depression, increase sunlight exposure and outdoor activities. Open the windows often to change the air. Listen to some relaxing music, talk to your friends, and participate in some sports and cultural activities; also pay attention to strengthening nutrition, eating high-calorie food, brain-healthy food, vegetables and fruits in moderation; work and rest on time, and improve the quality of sleep. If you suffer from winter depression, don’t worry, face up to the depression and don’t close yourself off. Communicate more with people you trust, while family members should also be more encouraging and actively cooperate with doctors for treatment. There are two kinds of treatment for winter depression: light therapy and medication, both of which have achieved good clinical results. Light therapy, which is a more fashionable treatment, is considered to be the first choice for winter depression because of its fast onset, high efficiency and basically no side effects. The specific treatment is to be performed under a fluorescent light whose class is sunlight, with the patient looking at the light source with open eyes but without gazing. The duration of each session is 10-15 minutes at first, gradually increasing to 30-45 minutes per day, and generally not exceeding 90 minutes. Most patients have significant results in 4-6 days of treatment, and continue to adhere to treatment to know full recovery. Medication can be used to treat antidepressants, such as fluoxetine, paroxetine, sertraline, citalopram, duloxetine, etc. For patients with anxiety symptoms, various anti-anxiety drugs such as Valium can be used in combination for a short period of time. In general, antidepressants can take effect in about two weeks after medication, and most patients can be significantly improved or cured within 2 months, and then maintain treatment for 8-12 months to prevent relapse. For people with severe negative thoughts and self-injurious tendencies, hospitalization is recommended.