Guillemette J, Hébert M, Paquet J, Dumont M
Laboratoire de chronobiologie, Hôpital du Sacré-Coeur de Montréal, Québec, Canada.
Biol Psychiatry. 1998 Oct 1;44(7):622-8. doi: 10.1016/s0006-3223(97)00543-x.
Considering the success of bright light therapy in seasonal affective disorders, it was suggested that seasonal mood disorders are triggered by decreased exposure to bright light in the winter; however, no previous studies have used objective measures to assess seasonal patterns of bright light illumination in subjects with seasonal mood variations.
Eleven subjects reporting seasonal mood variations and 8 control subjects had their levels of natural bright light (BL) exposure measured for 5-6 days with an ambulatory monitor during both the summer and winter, at a latitude of 45 degrees 31'N.
Both groups received significantly more BL in the summer than in the winter, but there was no difference between the two groups for the pattern of BL exposure, including total duration, daily distribution, and amplitude of seasonal variation.
These results suggest that complaints of seasonal mood variations are not caused by a differential pattern in bright light exposure compared to normals. It is possible, however, that some individuals are more sensitive than others to variations in natural bright light. Whether an increased vulnerability is due to a more fragile affective state or to a lower sensitivity to light remains to be determined.
鉴于强光疗法在季节性情感障碍治疗中的成功，有人提出季节性情绪障碍是由冬季暴露于强光的时间减少所引发；然而，此前尚无研究采用客观测量方法来评估有季节性情绪变化的受试者的强光照明季节性模式。
11名报告有季节性情绪变化的受试者和8名对照受试者，在北纬45度31分的地区，于夏季和冬季期间，使用动态监测仪对其自然光暴露水平进行了5至6天的测量。
两组在夏季接受的自然光均显著多于冬季，但两组在自然光暴露模式方面没有差异，包括总时长、每日分布以及季节性变化幅度。
这些结果表明，季节性情绪变化的主诉并非由与正常人相比不同的强光暴露模式所致。然而，有可能一些个体比其他个体对自然光变化更为敏感。这种易感性增加是由于情感状态更脆弱还是对光的敏感性较低，仍有待确定。
