They may carry out an assessment to check your mental health. If you have the symptoms of SAD, visit your GP. Read more about the effects of sunlight on melatonin, serotonin and the body's circadian rhythm. the body's circadian rhythm (the body's internal clock, which regulates several biological processes during a 24-hour period).the production of the hormone serotonin.the production of the hormone melatonin.In people with SAD, a lack of sunlight and a problem with certain brain chemicals stops the hypothalamus working properly. One theory is that light stimulates a part of the brain called the hypothalamus which controls mood, appetite and sleep.

However, it is not clear what this effect is. Sunlight can affect some of the brain's chemicals and hormones. The exact cause of SAD is not fully understood, but it is thought to be linked to reduced exposure to sunlight during the shorter days of the year. In most cases, the symptoms of SAD begin to improve in the spring before disappearing. They are most severe during December, January and February. The symptoms often begin in the autumn as the days start getting shorter. SAD is sometimes known as 'winter depression' because the symptoms are more apparent and tend to be more severe at this time of the year. Read more information about the symptoms of seasonal affective disorder. The episodes of depression tend to occur at the same time each year, usually during the winter.Īs with other types of depression, two of the main symptoms of SAD are a low mood and a lack of interest in life. Seasonal affective disorder (SAD) is a type of depression that has a seasonal pattern.

What does s ad mean