Department of Neurology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America.
PLoS One. 2012;7(6):e38761. doi: 10.1371/journal.pone.0038761. Epub 2012 Jun 12.
Major depression occurs at high prevalence in the general population, often starts in juvenile years, recurs over a lifetime, and is strongly associated with disability and suicide. Searches for biological markers in depression may have been hindered by assuming that depression is a unitary and relatively homogeneous disorder, mainly of mood, rather than addressing particular, clinically crucial features or diagnostic subtypes. Many studies have implicated quantitative alterations of motility rhythms in depressed human subjects. Since a candidate feature of great public-health significance is the unusually high risk of suicidal behavior in depressive disorders, we studied correlations between a measure (vulnerability index [VI]) derived from multi-scale characteristics of daily-motility rhythms in depressed subjects (n = 36) monitored with noninvasive, wrist-worn, electronic actigraphs and their self-assessed level of suicidal thinking operationalized as a wish to die. Patient-subjects had a stable clinical diagnosis of bipolar-I, bipolar-II, or unipolar major depression (n = 12 of each type). VI was associated inversely with suicidal thinking (r = -0.61 with all subjects and r = -0.73 with bipolar disorder subjects; both p<0.0001) and distinguished patients with bipolar versus unipolar major depression with a sensitivity of 91.7% and a specificity of 79.2%. VI may be a useful biomarker of characteristic features of major depression, contribute to differentiating bipolar and unipolar depression, and help to detect risk of suicide. An objective biomarker of suicide-risk could be advantageous when patients are unwilling or unable to share suicidal thinking with clinicians.
在普通人群中，重度抑郁症的发病率很高，通常在青少年时期发作，会终生反复发作，并与残疾和自杀密切相关。在抑郁症中寻找生物标志物的研究可能受到了阻碍，因为人们假设抑郁症是一种单一的、相对同质的疾病，主要是情绪障碍，而不是针对特定的、临床关键的特征或诊断亚型。许多研究都表明，抑郁患者的运动节律存在定量改变。由于一个具有重大公共卫生意义的候选特征是抑郁障碍中自杀行为的风险异常高，因此我们研究了从使用非侵入性腕戴式电子活动记录仪监测的抑郁患者（n = 36）的日常运动节律的多尺度特征中得出的一种测量方法（脆弱性指数[VI]）与他们自我评估的自杀思维水平（表现为想死的愿望）之间的相关性。患者的临床诊断为双相 I 型、双相 II 型或单相重度抑郁症（每种类型各 12 例）。VI 与自杀思维呈负相关（所有患者 r = -0.61，双相障碍患者 r = -0.73；均 p<0.0001），并能以 91.7%的敏感性和 79.2%的特异性区分双相和单相重度抑郁症患者。VI 可能是重度抑郁症特征的有用生物标志物，有助于区分双相和单相抑郁症，并有助于检测自杀风险。当患者不愿意或无法与临床医生分享自杀思维时，客观的自杀风险生物标志物可能会很有优势。
