Obsessive-compulsive disorder (OCD) symptoms fluctuate throughout the day, but scientists are not sure what underlies these fluctuations. One factor which may explain how OCD symptoms wax and wane throughout the day is alertness. Increased alertness is associated with greater inhibitory control, a factor which plays a significant role in patients’ ability to overcome their OCD symptoms. The current study examined the relationship between chronotype (morningness/eveningness preference, a measure of alertness) and within-day OCD symptom severity fluctuations. We hypothesized that increased alertness leads to better inhibitory abilities and, therefore, reduced OCD symptoms. OCD Symptoms were measured through 7-days of monitoring in which participants were asked to retrospectively rate their symptoms at several timepoints throughout the day. Chronotype was measured using the Morningness/Eveningness Questionnaire (MEQ). Consistent with our hypotheses, results revealed an interaction between chronotype and time of day, such that those with an eveningness preference tended to have worse symptoms in the morning, and vice versa. In addition, we also report novel findings regarding the effect of bedtime, sleep duration, and sleep quality on symptom severity the next day. Taken together, these findings suggest that alertness may modulate OCD symptom severity throughout the day such that individuals experience more severe symptoms during times of low alertness. The clinical and theoretical implications of these findings are discussed.

强迫症 (OCD) 的症状全天都在波动，但科学家们不确定这些波动的原因是什么。一个可以解释强迫症症状在一天中如何变化的因素是警觉性。提高警觉性与更强的抑制控制相关，这是一个在患者克服强迫症症状的能力中起着重要作用的因素。目前的研究调查之间的关系chronotype（早晨/傍晚偏好，警觉性的衡量标准）和日内强迫症症状严重程度波动。我们假设提高警觉性会导致更好的抑制能力，从而减少强迫症症状。强迫症症状是通过 7 天的监测来衡量的，其中要求参与者在一天中的几个时间点回顾性地评价他们的症状。使用晨间/晚间问卷（MEQ）测量时型。与我们的假设一致，结果揭示了睡眠类型和一天中的时间之间的相互作用，因此那些喜欢晚上睡觉的人在早上的症状往往更糟，反之亦然。此外，我们还报告了关于就寝时间、睡眠持续时间和睡眠质量对第二天症状严重程度的影响的新发现。综合起来，这些发现表明，警觉性可能会在一天中调节强迫症症状的严重程度，从而使个体在警觉性低下时会出现更严重的症状。讨论了这些发现的临床和理论意义。