Identifying and treating Seasonal Affective Disorder (SAD)
Season affective disorder (SAD) is a type of depression that appears related to seasonal changes. This recurrent depression may happen every year and occurs most commonly in the fall and winter when the daylight hours shorten, but it may also occur in the spring and summer. SAD may affect up to 5% of the population and seems to be more common in Northern climates and in individuals with a personal history of depression and those with a close relative who has depression. Symptoms include feelings of depression, hopelessness, or worthlessness, as well as sleep and appetite disturbances, low energy, and suicidal ideas or thoughts of death. Theories about etiology include consideration of the effect of fewer daylight hours, which may lead to a disruption of circadian rhythms and changes in serotonin and melatonin levels. Like other types of Major Depressive Disorder, SAD can contribute to poor functioning at work or school and in social situations. Substance use may increase in individuals with SAD. Individuals with SAD are also at risk for suicide.
It is important to treat SAD when symptoms are causing functional impairment, include suicidal thoughts, or are associated with risky substance use patterns. Assessment should include review of a physical examination and indicated laboratory evaluations. DSM-5 criteria are used to make the definitive diagnosis. In addition to antidepressant medication and psychotherapy, there is a body of evidence showing the efficacy of phototherapy or light therapy, which may be first line of defense for some patients with fall/winter SAD. Phototherapy involves exposure to a light box that emits light similar to natural outdoor light. This appears to cause an alteration in the neurotransmitters that are impacted by reduced exposure to sunlight. Light therapy has few side effects and may bring improvement in a few days, but can take a few weeks to take effect.