Seasonal affective disorder, or SAD, is a type of depression that occurs at a certain time of year. In most cases, symptoms begin in the fall and worsen throughout the winter before abating in the spring. SAD is a common depressive condition, affecting around 10 million Americans every year. Below, learn more about its causes, symptoms, and the role seasonal changes play in its trajectory.

Causes of SAD

Though the precise cause of SAD is not definitively known, it is thought that a change in sunlight is the primary trigger of the condition. Reduced or increased exposure to sunlight can upset a person's circadian rhythm. This disturbs their internal biological clock and impacts normal sleeping, eating, and activity patterns. Less sunlight can also decrease the production of serotonin, a neurotransmitter responsible for mood regulation. It can also increase the production of melatonin, a hormone that encourages sleepiness and lethargy.

Symptoms of the Disorder 

Feelings of depression, despair, hopelessness, and sadness are common with SAD. You might experience a general sense of fatigue, a loss of interest in activities you normally enjoy, or sleeping and eating more or less frequently than usual. Disruptive negative thinking, anxiety, or suicidal thoughts may also occur.

How the Seasons Affect SAD

The seasons figure prominently into the course of seasonal affective disorder mainly because of the changing hours of available sunlight. In winter, daylight hours are significantly reduced. In the gradual lead-up to winter throughout the fall, SAD symptoms may slowly emerge as available sunlight wanes. Then, at the height of winter, SAD can reach its most extreme point. However, as daylight hours increase closer to spring, symptoms may start to alleviate.

SAD can come on during the spring and summer, as well. In these instances, greater daylight decreases melatonin production and healthy sleep, so symptoms tend to fall on the more "active" end of the spectrum. The resulting symptoms may include sleeplessness, agitation, and poor appetite. 

If you experience any of the symptoms of seasonal affective disorder, make it a priority to consult a mental health professional. Daymark Recovery Services has been serving clients throughout North Carolina since 2004. They are a treatment center offering counseling and support for those dealing with depression and other mental illnesses and substance abuse issues. Call (336) 242-2450 or visit their website to schedule an appointment.