PHASE SHIFTING EFFECTS OF MELATONIN IN WINTER DEPRESSION

我们把所有的研究工作都集中在 生物节律在睡眠和情绪障碍中的作用。我们有 研究发现，人类夜间褪黑激素的产生受到抑制， 明亮的光。这一发现导致了明亮的光线在 早上为了引起相位提前，晚上为了 导致相位延迟。这些发现已被应用于 治疗昼夜节律紊乱，包括晚期和 睡眠时相延迟综合征、时差反应和轮班适应不良 工作对强光最敏感的疾病之一 治疗方法是冬季抑郁症。然而，目前尚不清楚是否或 这种疾病没有明显的生物节律成分。我们 提出了生物节律假说， 我们对这些病人为什么在冬天变得抑郁的了解 以及暴露在强光下是如何抗抑郁的。的相移 一种假说认为，冬季抑郁症的发病阶段延迟， 对短自然光周期的反应（晚黎明） 一年中的这个时候。它进一步指出，明亮的光线照射应该 在早上的时候是最抗抑郁的， 它将导致校正的昼夜节律相位提前。虽然 相移假说可能是最积极的测试 冬季抑郁症的假设，这是有争议的：一些研究 显示早晨的光线比晚上的光线更有抗抑郁作用， 其他研究显示没有差异。我们最近完成了 最大的一次比较是早晨和。黄昏的光在这 患者人群，其结果支持相移 假说.然而，尽管早晨的阳光更能抗抑郁， 比晚光，晚光抑郁评分低于 基准评级。因此，仍然有可能， 抗抑郁药对光的反应不依赖于一个阶段 提前本研究旨在确定是否存在 相位超前是晨光的重要组成部分， 抗抑郁作用它是基于我们最近发现的一种 外源性给予褪黑激素的相位响应曲线 人类：下午服用褪黑激素会导致一个阶段 类似于早晨暴露在阳光下引起的进展; 在早晨施用褪黑激素会引起相位延迟 类似于夜晚的光线。通过引起昼夜节律 通过一个完全不同的相位重置剂，我们可以 对相移假说进行了重要的检验。的 这项研究将进一步加深我们对光褪黑激素的理解 以及冬季抑郁症的生物节律。

We have concentrated all of our research efforts on the study of the role of biological rhythms in sleep and mood disorders. We have found that human nighttime melatonin production is suppressed by bright light. This discovery led to the use of bright light in the morning in order to cause a phase advance and in the evening to cause a phase delay. These findings have been applied in the treatment of circadian phase disorders, which include advanced and delayed sleep phase syndrome, jet lag and maladaptation to shift work. One of the most responsive disorders to bright light treatment is winter depression. However, it is not known whether or not this disorder has a significant biological rhythm component. We have proposed a biological rhythm hypothesis in order to further our knowledge of why these patients become depressed in the winter and how bright light exposure is antidepressant. The phase shift hypothesis states that winter depressives become phase delayed in response to the short natural photoperiod (the later dawn) at this time of year. It further states that bright light exposure should be most antidepressant when scheduled in the morning at which time it will cause a corrective circadian phase advance. Although the phase shift hypothesis is probably the most actively tested of the winter depression hypotheses, it is controversial: some studies show morning light to be more antidepressant than evening light, other studies show no difference. We have recently completed the largest single comparison of morning versus. evening light in this patient population, the results of which support the phase shift hypothesis. However, although morning light is more antidepressant than evening light, evening light depression ratings are lower than baseline ratings. Therefore, it is still possible that the antidepressant response to light is not dependent upon a phase advance. The present study proposes to determine whether or not a phase advance is a significant component of morning light's antidepressant effect. It is based on our recent discovery of a phase response curve for exogenous administration of melatonin in humans: administration of melatonin in the afternoon causes a phase advance similar to that caused by morning light exposure; administration of melatonin in the morning causes a phase delay similar to that caused by evening light. By causing circadian phase shifts through an entirely different phase-resetting agent, we can conduct an important test of the phase shift hypothesis. The proposed study should further our understanding of light melatonin and biological rhythms in winter depression.