Seasonal affective disorder

Seasonal affective disorder (SAD) is another name for a type of mood disorder whose mood episodes correspond to the seasons or characteristic times of the year.
==Seasonal pattern specifiers in the DSM==
Seasonal pattern specifiers are used to describe (or specify) the course of of some mood disorders whose mood episodes correspond to the seasons or characteristic times of the year.
The DSM uses seasonal pattern specifiers to describe the following mood disorders:
*Recurrent major depressive disorder
*Bipolar I disorder
*Bipolar II disorder
In order for a mood disorder to be considered to have a seasonal pattern the following must be true:
*There is a regular relationship between the beginning of a major depressive episode and the time of year (for example, depression regularly starting in the fall or winter)
*Full remissions also occur at a specific time of year (for example, depression disappears in the spring)
*In the last 2 years or more major depressive episodes have always and only occurred during a specific season
*Seasonal major depressive episodes have substantially outnumbered nonseasonal major depressive episodes throughout the person's lifetime
While this description does not specify the presence of manic, mixed, or hypomanic episodes, these types of episodes often also occur at other times of the year (for example, manic episodes during the summer).
== Causes ==
The specific cause of seasonal affective disorder remains unknown. Some factors that may come into play include:
* Your biological clock (circadian rhythm). The reduced level of sunlight in fall and winter may cause winter-onset SAD. This decrease in sunlight may disrupt your body's internal clock and lead to feelings of depression.
* Serotonin levels. A drop in serotonin, a brain chemical (neurotransmitter) that affects mood, might play a role in SAD. Reduced sunlight can cause a drop in serotonin that may trigger depression.
* Melatonin levels. The change in season can disrupt the balance of the body's level of melatonin, which plays a role in sleep patterns and mood.
== Treatment ==
Treatments can include: Light therapy, medications, psychotherapy (counseling), relaxation techniques, art therapy, and/or music therapy. 
Home remedies include Alternative medicine, increasing the amount of light in the home, exercise, and vacationing in sunny areas when possible. 
==External links==
Seasonal Affective Disorder Symptoms and Causes - The Mayo Clinic