Seasonal affective disorder: an overview.
Seasonal Affective Disorder (SAD) is a condition of regularly occurring depressions in winter with a remission the following spring or summer. In addition to depressed mood, the patients tend to experience increased appetite and an increased duration of sleep during the winter. SAD is a relatively common condition, affecting 1-3% of adults in temperate climates, and it is more prevalent in women. The pathological mechanisms underlying SAD are incompletely understood. Certain neurotransmitters have been implicated; a dysfunction in the serotonin system in particular has been demonstrated by a variety of approaches. The role of circadian rhythms in SAD needs to be clarified. The phase-delay hypothesis holds that SAD patients' circadian rhythms are delayed relative to the sleep/wake or rest/activity cycle. This hypothesis predicts that the symptoms of SAD will improve if the circadian rhythms can be phase-advanced. There is some experimental support for this. SAD can be treated successfully with light therapy. In classical light therapy, the SAD sufferer sits in front of a light box, exposed to 2000-10,000 lux for 30-120 min daily during the winter. Other forms of light treatments, pharmacotherapy, and other therapies are currently being tested for SAD.
Magnusson
Andres
A
Department of Psychiatry, Ullevaal University Hospital, Oslo, Norway. andres.magnusson@psykiatri.uio.no
Boivin
Diane
D
D002909:Chronobiology Phenomena; D002940:Circadian Rhythm; D006801:Humans; D008550:Melatonin / Q000502:physiology; D008954:Models, Biological; D017440:Photoperiod; D010789:Phototherapy; D016574:Seasonal Affective Disorder / Q000209:etiology / Q000503:physiopathology / Q000628:therapy; D012621:Seasons; D012701:Serotonin / Q000502:physiology
D012701:Serotonin; D008550:Melatonin