Clinical Research Unit, Brain & Mind Research Institute, University of Sydney, Camperdown, NSW, Australia.
Transl Psychiatry. 2012 May 29;2(5):e123. doi: 10.1038/tp.2012.47.
Although disturbances of the circadian system are strongly linked to affective disorders, no known studies have examined melatonin profiles in young people in early stages of illness. In this study, 44 patients with an affective disorder underwent clinical and neuropsychological assessments. They were then rated by a psychiatrist according to a clinical staging model and were categorized as having an 'attenuated syndrome' or an 'established disorder'. During the evening, salivary melatonin was sampled under dim light conditions over an 8-h interval and for each patient, the time of melatonin onset, total area under the curve and phase angle (difference between time of melatonin onset and time of habitual sleep onset) were computed. Results showed that there was no difference in the timing of melatonin onset across illness stages. However, area under the curve analyses showed that those patients with 'established disorders' had markedly reduced levels of melatonin secretion, and shorter phase angles, relative to those with 'attenuated syndromes'. These lower levels, in turn, were related to lower subjective sleepiness, and poorer performance on neuropsychological tests of verbal memory. Overall, these results suggest that for patients with established illness, dysfunction of the circadian system relates clearly to functional features and markers of underlying neurobiological change. Although the interpretation of these results would be greatly enhanced by control data, this work has important implications for the early delivery of chronobiological interventions in young people with affective disorders.
尽管昼夜节律系统的紊乱与情感障碍密切相关，但目前还没有已知的研究检查处于疾病早期阶段的年轻人的褪黑素谱。在这项研究中，44 名情感障碍患者接受了临床和神经心理学评估。然后，精神病医生根据临床分期模型对他们进行了评估，并将他们分为“衰弱综合征”或“已确立的障碍”。在傍晚，在暗光条件下采集 8 小时间隔内的唾液褪黑素样本，并为每位患者计算褪黑素起始时间、总曲线下面积和相位角（褪黑素起始时间与习惯性睡眠起始时间之间的差异）。结果表明，在疾病阶段之间，褪黑素起始时间没有差异。然而，曲线下面积分析表明，与“衰弱综合征”患者相比，“已确立的障碍”患者的褪黑素分泌水平明显降低，相位角更短。这些较低的水平反过来又与较低的主观嗜睡和神经心理学言语记忆测试的较差表现有关。总的来说，这些结果表明，对于患有已确立疾病的患者，昼夜节律系统的功能障碍与功能特征和潜在神经生物学变化的标志物明显相关。尽管这些结果的解释将通过对照数据得到极大增强，但这项工作对在患有情感障碍的年轻人中早期进行生物节律干预具有重要意义。
