Vagal fluctuation as a predictor of current and future depression

描述（由申请人提供）：抑郁症是所有精神疾病中最普遍的一种，占所有精神疾病经济成本的20%以上。一项重要的公共卫生优先事项是确定既增加个人患抑郁症的脆弱性又阻碍从这种疾病中恢复的因素。心脏迷走神经控制异常可能导致抑郁。更具体地说，心脏迷走神经控制的两种明显异常可能导致易感性：通常在静息状态下测量的低迷走神经水平（VL）和通常在响应环境需求时测量的低迷走神经波动（VF）。VL和VF越来越多地被理解为身体和心理健康结果的独立预测因子。迄今为止，情绪障碍的研究几乎完全集中在VL上，其病因和预后价值在很大程度上尚无定论。我们实验室的早期数据表明，抑郁症的特征是低VF，而VF可能预测临床显著抑郁症的后续病程。本R21探索性研究项目的广泛目标是调查VF作为抑郁症的责任标记。我们将使用一系列先前验证的实验室任务来引出60名诊断为当前单极抑郁症的门诊患者，30名过去诊断为单极抑郁症的参与者和30名健康的非精神病参与者的VF。VL和VF将通过心电图得出的高频心期变异性来评估。参与者将被纵向跟踪并在6个月后重新评估。本研究的主要目的是研究：(1)抑郁易感性是否与实验应激期间和应激后的VF降低相关；(2)在实验压力源期间和之后保持动态VF的抑郁个体是否更有可能在6个月后从障碍中恢复。研究人员打算将这些R21数据作为一个更大的R01研究资助项目的基础，该项目将研究VF与以下方面的关系：(a) MDD以外的精神疾病；(b)预测较长时期（~3年）的结果；(c)预测受控治疗方式的结果；(d) VF修饰的潜在抗抑郁作用。从公共健康的角度来看，抑郁风险与低VF有关的假设是令人兴奋的，因为它表明，易于获得和潜在可操作的心率变异性测量可以用于协助抑郁风险的早期评估，并且可能开发直接作用于迷走神经通路本身的干预措施。公共卫生相关性：一项重要的公共卫生优先事项是确定既增加个人易患抑郁症又阻碍从这种疾病中恢复的因素。心脏迷走神经控制异常可能导致抑郁。该项目将检验抑郁风险与缺乏动态心脏迷走神经控制有关的假设，这可能很重要，因为它表明，易于获得和潜在可操作的心率变异性测量可用于协助抑郁风险的早期评估，并可能开发直接作用于迷走神经通路本身的干预措施。

DESCRIPTION (provided by applicant): Depression is among the most prevalent of all psychiatric disorders, accounting for over 20% of economic costs for all mental illness. An important public health priority is the identification of factors that both increase individuals' vulnerability to depression and hinder recovery from this disorder. Abnormalities in cardiac vagal control may confer vulnerability to depression. More specifically, two distinct abnormalities in cardiac vagal control may confer vulnerability: low vagal level (VL) usually measured in a resting state, and low vagal fluctuation (VF), usually measured in response to environmental demands. VL and VF are increasingly understood as independent predictors of physical and mental health outcomes. To date, mood disorders research has focused almost exclusively on VL, with results largely inconclusive as to its etiological and prognostic value. Early data from our laboratory suggests that depression is characterized by low VF and that VF may predict the subsequent course of clinically significant depression. The broad objective of this R21 exploratory research project is to investigate VF as a liability marker for depression. We will use a battery of previously-validated laboratory tasks to elicit VF in 60 outpatients diagnosed with current unipolar depression, 30 participants with a past diagnosis of unipolar depression, and 30 healthy non-psychiatric participants. VL and VF will be assessed via high-frequency heart period variability derived from the electrocardiogram. Participants will be followed longitudinally and reassessed at six months. The specific aims of this project are to examine: (1) whether depression vulnerability is associated cross-sectionally with reduced VF during and after experimental stressors; and (2) whether those depressed individuals who preserve dynamic VF during and after experimental stressors are more likely to recover from their disorder six months later. The investigators intend to use these R21 data as the foundation for a larger R01 research grant project that will examine VF with respect to: (a) psychiatric disorders other than MDD; (b) predicting outcome over longer periods (~3 years); (c) predicting outcome in a controlled treatment modality; and (d) potential antidepressant effects of VF modification. From a public health perspective, the hypothesis that depression risk is related to low VF is exciting because it suggests that easily acquired and potentially manipulable measures of heart rate variability could be used to assist in the early assessment of depression risk, and perhaps to develop interventions that operate directly upon the vagal pathway itself. PUBLIC HEALTH RELEVANCE: An important public health priority is the identification of factors that both increase individuals' vulnerability to depression and hinder recovery from this disorder. Abnormalities in cardiac vagal control may confer vulnerability to depression. This project will examine the hypothesis that depression risk is related to a lack of dynamic cardiac vagal control, which is potentially important because it suggests that easily acquired and potentially manipulable measures of heart rate variability could be used to assist in the early assessment of depression risk, and perhaps to develop interventions that operate directly upon the vagal pathway itself.