Bright-Light Therapy in the Treatment of Mood Disorders

Bright-light therapy (BLT) is established as the treatment of choice for seasonal affective disorder/winter type (SAD). In the last two decades, the use of BLT has expanded beyond SAD: there is evidence for efficacy in chronic depression, antepartum depression, premenstrual depression, bipolar depression and disturbances of the sleep-wake cycle. Data on the usefulness of BLT in non-seasonal depression are promising; however, further systematic studies are still warranted. In this review, the authors present a comprehensive overview of the literature on BLT in mood disorders. The first part elucidates the neurobiology of circadian and seasonal adaptive mechanisms focusing on the suprachiasmatic nucleus (SCN), the indolamines melatonin and serotonin, and the chronobiology of mood disorders. The SCN is the primary oscillator in humans. Indolamines are known to transduce light signals into cells and organisms since early in evolution, and their role in signalling change of season is still preserved in humans: melatonin is synthesized primarily in the pineal gland and is the central hormone for internal clock circuitries. The melatonin precursor serotonin is known to modulate many behaviours that vary with season. The second part discusses the pathophysiology and clinical specifiers of SAD, which can be seen as a model disorder for chronobiological Received: March 27, 2009 Accepted after revision: August 11, 2009 Published online: July 29, 2011 Siegfried Kasper, MD Department of Psychiatry and Psychotherapy Medical University of Vienna, Währinger Gürtel 18–20 AT–1090 Vienna (Austria) Tel. +43 1 40400 3568, E-Mail sci-biolpsy @ meduniwien.ac.at © 2011 S. Karger AG, Basel 0302–282X/11/0643–0152$38.00/0 Accessible online at: www.karger.com/nps D ow nl oa de d by : 54 .7 0. 40 .1 1 11 /1 9/ 20 17 3 :0 0: 09 P M