PHASE SHIFTING EFFECTS OF MELATONIN IN WINTER DEPRESSION

我们把所有的研究努力都集中在研究 生物节律在睡眠和情绪紊乱中的作用。我们有 发现人类夜间褪黑激素的产生受到抑制 明亮的灯光。这一发现导致了在地球上使用强光 早上为了引起阶段推进，晚上为了 造成相位延迟。这些发现已被应用于 昼夜节律紊乱的治疗，包括晚期和 睡眠相延迟综合征、时差和换班适应不良 工作。对强光最敏感的障碍之一 治疗方法是冬季抑郁症。然而，目前还不知道是否或 并不是这种疾病有显著的生物节律成分。我们 提出了生物节律假说，以进一步 我们对这些患者在冬天变得抑郁的了解 以及暴露在强光下有多抗抑郁。相移 假说表明，冬季抑郁症患者的阶段会延迟 对较短的自然光周期(黎明较晚)的反应 一年中的这个时候。它进一步指出，强光照射应该 计划在早上的什么时间服用最抗抑郁的药物 它将导致校正的昼夜节律相位提前。尽管 相移假说可能是最活跃的测试 冬季抑郁症假说，存在争议：一些研究 显示晨光比晚光更具抗抑郁作用， 其他研究表明没有什么不同。我们最近完成了 晨间对比的最大单次比较。这里的傍晚光线 患者群体，其结果支持相变 假设。然而，尽管早晨的阳光更具抗抑郁作用 比晚间灯光、晚间灯光郁闷评级更低 基准评级。因此，仍有可能 抗抑郁药对光的反应不依赖于一个时相 前进。本研究建议确定是否有一个 相位提前是晨光的一个重要组成部分 抗抑郁作用。它是基于我们最近发现的一种 褪黑素外源性给药的时相反应曲线 人类：下午服用褪黑素会引起一段时间 与晨光照射所引起的推进相似； 早上服用褪黑素会导致时相延迟 类似于由晚光引起的。通过引起昼夜节律 通过一种完全不同的相位重复剂，我们可以 对相移假说进行重要的检验。这个 拟议的研究将进一步加深我们对光褪黑素的理解 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.