Thompson C, Childs P A, Martin N J, Rodin I, Smythe P J
University of Southampton, Hampshire.
Br J Psychiatry. 1997 May;170:431-5. doi: 10.1192/bjp.170.5.431.
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.
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.
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.
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.
对于季节性情感障碍（SAD）患者，凌晨00:30的光照对褪黑素的抑制作用在冬季比夏季更为明显，但在匹配的正常对照者中并非如此。
在本研究中，12名SAD患者和12名匹配的正常对照者在冬季接受晨光照疗法。在治疗前后测量褪黑素水平和对光的敏感性。
SAD组而非正常组在接受光疗后褪黑素节律出现相位提前。在SAD组中，相位位置与相位偏移之间存在关联，而正常组中则不存在。
SAD患者的昼夜节律可能存在不稳定性，这是由高振幅相位反应曲线介导的，而非如先前所认为的固定相位异常。这种不稳定性可能继发于视交叉上核传入通路中5-羟色胺能功能受损。
