An estimated 6 percent of Americans suffer from seasonal affective disorder (SAD), a type of depression, and an additional 14 percent experience a milder form of the disorder known as the winter blues. SAD strikes during the winter months and is associated with reduced exposure to sunlight. People with SAD suffer from irritability, apathy, carbohydrate craving and weight gain, increases in sleep time, and general sadness. Researchers believe that SAD is caused by a malfunction in the hypothalamus, the gland responsible for regulating responses to external stimuli. Stress may also playa role in SAD. Certain factors seem to put people at risk for SAD. Women are four times more likely to suffer from SAD than are men. Although SAD occurs in people of all ages, those between 20 and 40 appear to be most vulnerable. Certain families appear to be at risk. And people living in northern states in the United States are more at risk than are those living in southern states. During the winter, there are fewer hours of sunlight in northern regions than in southern areas. An estimated 10 percent of the population in northern states such as Maine, Minnesota, and Wisconsin experience SAD, whereas fewer than 2 percent of those living in southern states such as Florida and New Mexico suffer from the disorder.

There are some simple but effective therapies for SAD. The most beneficial appears to be light therapy, in which a patient is exposed to lamps that mimic sunlight. After being exposed to this lighting each day, 80 percent of patients experience relief from their symptoms within four days. Other forms of treatment for SAD are diet change(eating more foods high in complex carbohydrates), increased exercise, stress management techniques, sleep restriction(limiting the number of hours slept in a 24-hour period), psychotherapy, and antidepressants.

Obsessive-Compulsive Disorders

Approximately 5 million Americans suffer from obsessive-compulsive disorders. An obsessive-compulsive disorder(OCD) is an illness in which people have obsessive thoughts or perform habitual behaviors that they cannot control. People with obsessions have recurring ideas or thoughts that they cannot control. People with compulsions feel forced to engage in a repetitive behavior, almost as if the behavior controls them. Feeling an obsessive need for cleanliness and washing one's hands 20 times before eating, counting to a certain number while using the toilet, and checking and rechecking all the light switches in the house before leaving or going to bed are examples of compulsive behaviors. OCD may be considered one type of depression.

Many people suffers from seasonal affective disorder, a type of depression.