(Medical Xpress) -- It happens every year the shortened daylight hours of the winter months always seem to affect ones mood. People of all ages can develop seasonal affective disorder (SAD), a type of clinical depression which occurs at a particular time of the year, usually during the fall and winter, and resolving by spring.
Seasonal affective disorder appears to be triggered by alterations in the circadian rhythm (daily rhythms in hormone secretion and cellular function) due to reduced sunlight exposure, says Eric Lenze, MD, professor of psychiatry at Washington University School of Medicine in St. Louis, who specializes in the treatment of depression and anxiety disorders in older adults.
About one in 20 people will develop seasonal affective disorder, with a higher rate in more northern climates.
People with seasonal affective disorder may experience fatigue, feelings of sadness and anxiety, crying spells, irritability, trouble concentrating, body aches, loss of sex drive, poor sleep, decreased activity level and overeating.
Lenze says bright light therapy, sometimes called phototherapy, is the treatment of choice for seasonal affective disorder. Bright therapy is available in the form of fluorescent light boxes, which provide full-spectrum visible light at 10,000 lux (a measurement of light intensity). Less powerful light (2,500 5,000 lux) may be used as well.
Light therapy facts:
-- Positioning: Face should be about two feet from the light source. Staring in the light is not necessary.
-- Time: Thirty minutes per day (usually in the morning), more time for less powerful light source.
-- Onset of benefits: Three to seven days after starting light therapy.
-- Duration: Benefits will vanish after discontinuing use. Continue use until usual offset of symptoms.
-- Adverse side effects: Minimal. Patients with eye problems or a family history of retinal damage should consult their ophthalmologist. In any case, UV light should be avoided.
-- Non-response: Double exposure time; consider antidepressants and/or psychotherapy.
Antidepressant medications have also been found to be an effective treatment for seasonal affective disorder, particularly those from the serotonin selective reuptake inhibitor family, especially if symptoms are severe.
Some who believe that they may be suffering from seasonal affective disorder may actually be experiencing major depression or an anxiety disorder, Lenze says. Major depression and anxiety disorders are serious problems with significant distress, disability, disruption in interpersonal relationships and adverse health effects.
With appropriate treatment using medications and psychotherapy, most individuals with clinical depression and anxiety disorders can achieve remission. Unfortunately, most people with these disorders do not seek treatment, or do not get adequate treatment, he says.
Explore further: Winter holidays prime time for depression