BACKGROUND: The suppression of melatonin by light at 00.30 hours has been shown to be greater in winter than in summer on patients with seasonal affective disorder (SAD) but not in matched normal controls. METHOD: In this study 12 patients with SAD and 12 matched normal controls were exposed to morning light therapy in the winter. Melatonin profiles and sensitivity to light were measured before and after treatment. RESULTS: The SAD but not the normal group showed a phase advance of melatonin rhythms in response to phototherapy. There was an association between phase position and phase shift in the SAD but not in the normal group. CONCLUSIONS: There may be instability of circadian rhythms in SAD mediated by a high-amplitude phase response curve, rather than a fixed phase abnormality as had been previously suggested. This instability may be secondary to impaired serotoninergic function in the afferent pathways to the suprachiasmatic nuclei.
BACKGROUND: The suppression of melatonin by light at 00.30 hours has been shown to be greater in winter than in summer on patients with seasonal affective disorder (SAD) but not in matched normal controls. METHOD: In this study 12 patients with SAD and 12 matched normal controls were exposed to morning light therapy in the winter. Melatonin profiles and sensitivity to light were measured before and after treatment. RESULTS: The SAD but not the normal group showed a phase advance of melatonin rhythms in response to phototherapy. There was an association between phase position and phase shift in the SAD but not in the normal group. CONCLUSIONS: There may be instability of circadian rhythms in SAD mediated by a high-amplitude phase response curve, rather than a fixed phase abnormality as had been previously suggested. This instability may be secondary to impaired serotoninergic function in the afferent pathways to the suprachiasmatic nuclei.
Authors: Layan Zhang; Daniel S Evans; Uttam K Raheja; Sarah H Stephens; John W Stiller; Gloria M Reeves; Mary Johnson; Kathleen A Ryan; Nancy Weizel; Dipika Vaswani; Hassan McLain; Alan R Shuldiner; Braxton D Mitchell; Wen-Chi Hsueh; Soren Snitker; Teodor T Postolache Journal: J Affect Disord Date: 2014-11-28 Impact factor: 4.839
Authors: Catharina Lavebratt; Louise K Sjöholm; Pia Soronen; Tiina Paunio; Marquis P Vawter; William E Bunney; Rolf Adolfsson; Yvonne Forsell; Joseph C Wu; John R Kelsoe; Timo Partonen; Martin Schalling Journal: PLoS One Date: 2010-02-24 Impact factor: 3.240
Authors: Barbara L Parry; Charles J Meliska; L Fernando Martínez; Ana M López; Diane L Sorenson; Richard L Hauger; Jeffrey A Elliott Journal: Psychiatry Res Date: 2008-09-11 Impact factor: 3.222
Authors: Louise K Sjöholm; Lena Backlund; Emarndeena Haji Cheteh; Inger Römer Ek; Louise Frisén; Martin Schalling; Urban Osby; Catharina Lavebratt; Pernilla Nikamo Journal: PLoS One Date: 2010-09-09 Impact factor: 3.240
Authors: Reeta Rintamäki; Sharon Grimaldi; Ani Englund; Jari Haukka; Timo Partonen; Antti Reunanen; Arpo Aromaa; Jouko Lönnqvist Journal: PLoS One Date: 2008-01-23 Impact factor: 3.240