Seasonal affective disorder, or SAD, is depression that sets in during winter and goes away during spring and summer. Symptoms include exhaustion, weight gain, and carbohydrate cravings. SAD is linked to lack of sunlight and may be caused by hormonal changes triggered by winter’s extra dark hours. SAD is often treated with light therapy, during which a specialized light box is used as a replacement for the sun’s rays.
Directly Addresses SAD Cause
Light therapy directly addresses the cause of SAD–lack of sunlight. During light therapy, you sit near a very bright set of fluorescent bulbs that mimic an outdoor day’s sunlight. Sessions of light therapy last for 30 to 90 minutes. While the American Psychiatric Association cautions that the exact mechanisms of light therapy are unknown, it’s thought that the light may stimulate the brain to reshift its internal clock and release fewer depression-provoking hormones.
Kids Health, a Nemours hospital network information site, estimates that 6 percent of the population experiences seasonal affective disorder at one point during their life. It can affect individuals of all ages but is more likely to occur in women, those with relatives who have mental illness and individuals who often experience depression. Individuals who live in high altitude locations are more likely to experience seasonal affective disorder, reports the DSM-IV-TR. This is because during the winter in these geographic areas, the days are shorter and individuals are exposed to less sunlight.
According to the Environmental Illness Resource, researchers have linked seasonal affective disorder to the chemical in the brain called melatonin. Melatonin’s role is to induce sleep throughout the body. The brain begins to produce melatonin after the sun goes down. Its production occurs during the night hours, when an individual is supposed to sleep. When the sun rises, the brain stops producing melatonin, thus causing an individual to wake up in the morning. During winter months, the sun is out for less time, meaning the days are shorter days and the nights are longer. This causes the brain to produce melatonin for longer periods of time.
Individuals with seasonal affective disorder have higher levels of daytime melatonin during the winter months, due to shorter days and longer nights, reports the Environmental Illness Resource. This causes these individuals to be lethargic during the day, experience a decrease in motivation and want to sleep more often during daylight hours.
If you believe you are suffering from seasonal affective disorder, consult a psychiatrist or physician. A physician can clarify the causes of your depression and whether it is due to other factors besides melatonin. Do not try to diagnose yourself with seasonal affective disorder or any other type of mental illness.