Seasonal Affective Disorder (SAD) is a disturbance in mood associated with the time of year. Most commonly, SAD occurs during the Fall and Winter months, with symptoms remitting during the sunnier seasons of Spring and Summer. Up to 5 percent of the U.S. population experiences SAD in a given year. Symptoms include feeling depressed, loss of interest in activities one normally enjoys, low energy, sleep disturbances, changes in appetite and/or weight, agitation, difficulty concentrating, feelings of worthlessness or hopelessness, and frequent thoughts of death or suicide. SAD is more common in women, with a female-to-male ratio of 4:1. The etiology is thought to be related to circadian rhythm shifts and changes in levels of serotonin and melatonin which occur with reduced sunlight. Treatment is aimed at improving symptoms as well as for prophylaxis prior to the Winter months. Treatments include light therapy, antidepressant therapy, cognitive behavioral therapy, and TMS.
Light therapy (aka phototherapy) involves sitting a few feet from a light box that emits bright light. The light is intended to mimic outdoor light with the harmful ultraviolet (UV) rays filtered out. There are standardized guidelines which include a fluorescent light source at a standardized dosage for 30 minutes daily within the first hour of waking up. The eyes must be open, but one is not required to look directly into the light. Therefore, reading or eating during the therapy is acceptable. Light therapy units can be purchased from retail stores or online, and some insurance companies may cover the cost if the physician provides a prescription.
Selective serotonin reuptake inhibitors and serotonin-norepinephrine reuptake inhibitors have been shown to be superior to placebo in the treatment of SAD, with fluoxetine (Prozac) being the most studied drug. Treatment with fluoxetine has been shown to have approximately equal efficacy to light therapy. Cognitive behavioral therapy (CBT) has also been shown to be effective in treating SAD. Light therapy, SAD-tailored CBT, and the combination of both treatments all showed reduction in symptoms and remission rates which were comparable. However, the CBT group had a reduction in recurrences of depression in the subsequent year, which suggests that CBT may be a good option for prophylaxis. Also, TMS is a relatively new neuromodulation approach to treat depression. TMS is a safe outpatient procedure that can improve depression without medication and is associated with minimal side effects. In general, the recommendation is that patients with a history of SAD begin light therapy in the Autumn, before symptoms appear. Medication, CBT, and TMS can be utilized based on patient preference and past response. Additional strategies to target symptoms of SAD include getting regular exercise, creating a brighter environment in the home and workplace, going outside more frequently, and visiting sunnier climates.