The Center for Chronobiology, Department of Psychiatry, University of California, San Diego, La Jolla, California, USA.
Chronobiol Int. 2011 May;28(5):415-24. doi: 10.3109/07420528.2011.567365.
The authors previously observed blunted phase-shift responses to morning bright light in women with premenstrual dysphoric disorder (PMDD). The aim of this study was to determine if these findings could be replicated using a higher-intensity, shorter-duration light pulse and to compare these results with the effects of an evening bright-light pulse. In 17 PMDD patients and 14 normal control (NC) subjects, the authors measured plasma melatonin at 30-min intervals from 18:00 to 10:00 h in dim (<30 lux) or dark conditions the night before (Night 1) and after (Night 3) a bright-light pulse (administered on Night 2) in both follicular and luteal menstrual cycle phases. The bright light (either 3000 lux for 6 h or 6000 lux for 3 h) was given either in the morning (AM light), 7 h after the dim light melatonin onset (DLMO) measured the previous month, or in the evening (PM light), 3 h after the DLMO. In the luteal, but not in the follicular, phase, AM light advanced melatonin offset between Night 1 and Night 3 significantly less in PMDD than in NC subjects. The effects of PM light were not significant, nor were there significant effects of the light pulse on melatonin measures of onset, duration, peak, or area under the curve. These findings replicated the authors' previous finding of a blunted phase-shift response to morning bright light in the luteal, but not the follicular, menstrual cycle phase in PMDD compared with NC women, using a brighter (6000 vs. 3000 lux) light pulse for a shorter duration (3 vs. 6 h). As the effect of PM bright light on melatonin phase-shift responses did not differ between groups or significantly alter other melatonin measures, these results suggest that in PMDD there is a luteal-phase subsensitivity or an increased resistance to morning bright-light cues that are critical in synchronizing human biological rhythms. The resulting circadian rhythm malsynchonization may contribute to the occurrence of luteal phase depressive symptoms in women with PMDD.
作者先前观察到经前期烦躁障碍（PMDD）女性对早晨明亮光线的相移反应迟钝。本研究的目的是确定使用更高强度、更短持续时间的光脉冲是否可以复制这些发现，并将这些结果与傍晚明亮光脉冲的效果进行比较。在 17 名 PMDD 患者和 14 名正常对照组（NC）受试者中，作者在卵泡期和黄体期月经周期的前一天晚上（第 1 天晚上）和之后（第 3 天晚上），在昏暗（<30 勒克斯）或黑暗条件下，每隔 30 分钟测量一次血浆褪黑素，在前一个月测量的暗光褪黑素开始后 7 小时（DLMO）给予明亮光脉冲（第 2 天晚上给予）。明亮光（3000 勒克斯 6 小时或 6000 勒克斯 3 小时）分别在上午（AM 光）或傍晚（PM 光）给予，即在前一天晚上测量的 DLMO 后 3 小时或 7 小时给予。在黄体期，但不在卵泡期，与 NC 受试者相比，PMDD 患者的 AM 光使第 1 天晚上和第 3 天晚上之间的褪黑素消退明显延迟。PM 光的作用不显著，光脉冲对褪黑素开始、持续时间、峰值或曲线下面积的测量也没有显著影响。这些发现复制了作者先前的研究结果，即在 PMDD 中，与 NC 女性相比，早晨明亮光对黄体期月经周期相位的相移反应迟钝，但对卵泡期没有影响，与之前使用的较暗（3000 勒克斯）光脉冲相比，使用更亮（6000 勒克斯）光脉冲持续时间更短（3 小时）。由于 PM 强光对褪黑素相移反应的影响在组间没有差异，也没有显著改变其他褪黑素测量值，因此这些结果表明，在 PMDD 中，存在黄体期敏感性降低或对早晨明亮光线索的抵抗力增加，这对于同步人体生物节律至关重要。由此产生的昼夜节律失调可能导致 PMDD 女性黄体期抑郁症状的发生。
