Seasonal affective disorder is commonly known as seasonal depression or the “winter blues.” It is a subtype of major depression that occurs due to changes in climate and seasonal weather. Sunlight plays a critical role in the decreased serotonin activity, increased melatonin production, disrupted circadian rhythms, and low levels of Vitamin D associated with symptoms of SAD.
People with SAD may also have difficulty with overproduction of melatonin. Melatonin is a hormone produced by the pineal gland that responds to darkness by causing sleepiness. Melatonin promotes calmness and relaxation, helping individuals rest their bodies and minds in order to fall asleep
Melatonin is a hormone produced in the pineal gland in the brain. Its production is controlled by body’s master clock, found in the suprachiasmatic nucleus.
During the day, hormone melatonin levels are low. But as it gets dark, optic nerves send signals to the master clock, which signals the brain to begin producing melatonin.
People who suffer from SAD may overproduce melatonin, causing them to feel sleepy and lethargic during the day. This is common for people who experience SAD in the winter.
Hormone melatonin in seasonal affective disorder (SAD)
