Seasonal affective disorder, also know as SAD, is caused by low levels of light with disturbances in brain chemistry. Serotonin, melatonin, and dopamine are the imbalances in the brain. Low levels of these causes depression.
SAD is different from other forms of depression, as it only occurs annually during daylight savings time. The start of winter with a sudden change in daylight hours starts the onset of depression. It usually clears up on its own once the days become brighter and longer.
Symptoms of SAD may consist of difficulty of waking up in the mornings, lack of everyenergy, difficulty competing tasks, overeating, and also a craving for carbohydrates, which in turn causes weight gain. These symptoms also mimic major depressive disorder, which can run the rick of suicide in some individuals.
Light of at least 2500 lux is needed for most to sustain melatonin levels. During the winter months most people get only 500-1,000 lux due to low lighting in the workplace and or cloud coverage during the day. A sunny day gives brightness of 100,000 lux. Therefore, when there is not enough light, therapy is needed to increase the lux. This is known as phototherapy.
Phototherapy involves sending visible light through the eyes so that it reaches, and triggers, the pineal gland. There are different forms of light therapy used today, the oldest being natural sunlight itself. You can also use bright light therapy, which is a specific wavelength of light using lasers, light emitting diodes or, fluorescent lamps. The amount needed each day is about three hours. If you do not use the daily allotted time, you can fall back into a depression.
Serotonin, melatonin, and dopamine are hormones in the brain. Serotonin makes you feel calm, balanced and in control. Lack of this hormone can cause depression and poor concentration. Melatonin promotes sleep. If you do not have enough serotonin then melatonin can take over and make you feel sleepy. Melatonin is produced during hours of darkness that is why levels are at their lowest in spring and summer and higher in autumn and winter. Dopamine is another chemical whose production is stimulated by light and suppressed by melatonin.
Depending on your symptoms, SAD can be easily treated with the light therapy and or antidepressants. Once daylight savings time ends, your depression will lift and you should return back to normal.