Seasonal Affective Disorder

Many people suffer from a type of depression or “blah” feeling during the winter months! 

Winter in Pennsylvania (and father North) can be difficult to endure.  Did you know that your “winter blues” may have a name?  Frequently recurring depressive symptoms that follow a predicable seasonal pattern is also known as Seasonal Affective Disorder or SAD.

Definition of SAD

According to the DSM IV, Seasonal Affective Disorder is characterized by a pattern of depression that can begin and end with a certain season.  

The majority of cases of SAD begin with the start of the winter season and end with the start of spring or summer.

For patients who suffer from SAD, it usually has a predictable pattern of symptom arrival as well as abatement

Approximately, 14.8 million U.S. adults suffer from depression (about 7% of the population aged 18 and older).

An estimated 10-20% of those suffering from recurrent depression have a seasonal pattern to their symptoms.

Hallmarks of Seasonal Affective Disorder

Most SAD have the following characteristics:  three out of 4 are women, they tend to be between the ages of 10 and 30 years old, and live in North America.

Most SAD sufferers have their worst symptoms during the winter.  Symptoms may include:  feeling depressed most days, sleep disturbances, low self-esteem, overeating (leading to weight gain),  loss of libido, and avoidance of social contact,  feeling hopeless or worthless, having low energy and a loss of interested in activities you once enjoyed. 

Theories of the Development of SAD

Most current research on SAD has concentrated on the amount of light (sunlight) a person receives during different months, serotonin depletion and melatonin levels. 

Research has also concentrated on the latitude that a person lives on and it’s correlation to the development of SAD. 

Researchers have found rates of SAD in North America to be 1.4% to 9.7% depending on the area that you live.  In Europe, studies have shown a much lower rate of SAD; approximately 1.3% to 3% and the lower prevalence of SAD comes from Asia at a rate  as low as 0.9%.

Current theories discuss the reduction of daylight hours to be directly reflective of the development of SAD symptoms. 

Areas with fewer daylight hours during the winter months in addition to areas of extreme latitude tend to have higher levels of SAD reported.

SAD also appears to have a familial tendency.  Between 13-17% of those affected with SAD has a first degree relative also affected..

Humans have adapted their activities over millennia to seasonal activities and daylight available. 

This has become known as the “circadian rhythm”. 

When the seasons change, a shift in the human biological clock occurs. 

This is due in part to the varying degrees in sunlight patterns during different seasons.

The melatonin in the blood of persons who suffer from SAD also can be increased during times when there is less sunlight.  Melatonin is a hormone that is secreted by the Pineal gland of the brain that helps people regulate their sleep.  In periods of increased darkness, the pineal gland makes more melatonin. 

Increased levels of melatonin have been linked to changes to sleep patterns and mood. 

Scientists have postulated that people with SAD make more melatonin during the winter months to promote an increase of the amount of sleep while the duration of darkness also increases.

The amount of light as well as the intensity of light that humans get during different seasons has also been studied.  During the seasons with shorter periods of available daylight and the lack of intensity of winter daylight stimuli to the retina in individuals couple together to jump-start symptoms of SAD.

Risk Factors for SAD. Individuals who are female, are between the ages of 20 and 40 with a family history of major depression or SAD, patients who also suffer from Bipolar disorder are at greater risk for SAD.  Patients who live far from the equator are also at an increased risk.

Treatments of Seasonal Affective Disorder.

The treatment that has been investigated the most in patients with SAD is light-therapy.  Exposing patients to a light box daily during the months they experience symptoms has been shown to decrease symptomology in patients with SAD.

Retinal exposure of light is essential in decreasing SAD symptoms.  Patients who received only light directed to their skin saw little or no change in the presentation of SAD symptoms.

Recommendations for light therapy can only be made by your physician after a thorough examination and history.