Depression symptoms appear every winter It is 'seasonal affective disorder'?

It is said that about 5% of people in the United States appeal for somnolence, tiredness, depressed mood, etc. in the winter as winter becomes winter every year and day becomes shorter. It is a type of mood disorder called seasonal affective disorder, and in most cases it is said to be caused only in the winter of the year.

How to deal with seasonal affective disorder and stay alert this winter | Popular Science
https://www.popsci.com/how-to-treat-seasonal-affective-disorder

Why the seasonal affective disorder is caused and why it is limited to winter is not clearly understood at the biochemical level. Researchers hypothesize that changes in the amount of sunlight cause hormonal changes in people, including specific genes, and are influencing in the form of seasonal depression.

There are also research results that people living in the high latitude area have a higher incidence of seasonal affective disorder. According to the National Institutes of Health , in particular, in Alaska located in the northern part, only 9% of people with seasonal affective disorder were in the southern residents such as Florida, only 1% . "People suffering from a seasonal affective disorder can not change the sleep-awake period according to the winter moon-night cycle in which the circadian rhythm is disturbed and bring about changes in sleep, mood, and behavior," The National Institutes of Health comments .

Light therapy is said to be effective as a treatment for seasonal affective disorder. Light therapy is a method of bathed in the whole body for 10 to 15 minutes by using a UV-filtered LED white light bulb called "Happy lamp". There are studies that the circadian rhythm is disturbed by the light coming out from the screen of the smartphone or the PC and sleep disturbance is caused, but light therapy uses this to adjust the circadian rhythm by light. According to a study , it is said that symptoms of seasonal affective disorder have been alleviated by performing light therapy for 2 to 5 weeks in the month when the sunlight is least abundant.

Also, it is said that 'simulation of dawn' is effective for people who are relatively symptomatic. Simulation of dawn is to replace alarm sound of alarm clock with light of Happy lamp. For example, if you want to get up at 6:30 in the morning, the alarm clock starts 30 minutes early in the morning at 6 o'clock. And the happy lamp in the room increases brightly little by little over 30 minutes and the brightness of the daybreak is reproduced in the room. By mimicking the natural process that the body can understand, it reduces the severity of symptoms of seasonal affective disorder.

For seasonal affective disorders, counseling and taking antidepressant medications for general depression are not very effective, and relapse is prevented by performing such light therapy or dawn simulation There seems to be a theory that there is also. People with seasonal affective disorders often discuss with Popular Science that they are consulting with their family doctors and it is important to know how much their symptoms are declared and what is the right treatment for them.