While the majority of extant research has focused on the link between sleep disturbance and depression (Armitage, 2007), a growing body of research has implicated sleep disturbance in anxiety-related disorders (Cox & Olatunji, 2016), and recent research suggests that sleep disturbance predicts the development of an anxiety disorder (Batterham et al., 2012; Neckelman et al., 2007). Further, anxiety-related disorders and depression are highly comorbid (Kessler et al., 2003), and extant research is equivocal on whether the link between sleep disturbance and anxiety-related disorders is accounted for by depression. Study one examines the relationship between sleep disturbance and obsessive- compulsive symptoms in a nationally representative sample and tests whether depression accounts for this relationship.
Similarly, self- reported sleep disturbance has been linked to OCS in clinical and unselected samples. The available evidence suggests that the presence of sleep disturbance may compound the severity and impairment of OCD (Ivarsson & Skarphedinsson, 2015; Robinson et al., 1998).
Materials and Methods
Although some research suggests that the link between subjective sleep disturbance and symptoms of OCD is not accounted for by depression (Timpano et al., 2014), others have found that depression may explain this relationship (Diaz-Roman et al., 2015). Given the inconsistent findings in the literature, the present study also examined the extent to which sleep disturbance severity is associated with OCS severity when controlling for depression. Sleep disturbance was assessed in the Chronic Conditions section of the CIDI 3.0 with 4 yes/no items each measuring problems with sleep initiation, sleep.
First, an independent samples t-test was conducted to assess whether individuals who report sleep disturbance report increased OCS severity compared to individuals who do not report sleep disturbance. Second, an analysis of covariance (ANCOVA) was conducted to assess whether sleep disturbance severity is.
Results
In the present study, depression was defined as experiencing a major depressive episode in the past 12 months. Depression was included in the model because depression is often comorbid with OCD (Ruscio et al., 2010) and sleep. As shown in Table 1.3, results of an ANCOVA revealed that sleep disturbance severity was significantly associated with OCS severity when controlling for depression, F p < 0.001.
Discussion
The present study also found that sleep disturbance severity is associated with OCS severity, even when controlling for depression. However, the results of the present study indicate that increased sleep disturbance severity is linked to increased levels of OCS, and this relationship is not accounted for by co-occurring depression. The present study also extends previous research in showing that the link between increased sleep disturbance and increased levels of OCS is also not accounted for by co-occurring anxiety disorder diagnoses.
Future research is necessary to elucidate mechanisms that may explain why sleep disturbance is linked to OCS. The present results offer evidence of a unique link between sleep disturbance and anxiety-related symptoms in a nationally representative sample.
Introduction
Although the majority of extant research on sleep disturbance and repetitive thought has been focused on worry (Pillai & Drake, 2015), rumination, or engaging in negative thoughts related to perceived threats to the self or distressing experiences (Trapnell & Campbell, 1999), is also linked to poor sleep in healthy and clinical populations (Borders, Rothman, & McAndrew, 2014; Slavish & Graham-Engeland, 2015). Taken together, these findings indicate a link between sleep and maladaptive repetitive thought, such as worry and rumination, in healthy and clinical populations, including those with anxiety-related disorders. Despite increasing evidence supporting a relationship between sleep and maladaptive repetitive thought, the mechanism that may explain this link is unclear.
The relationship between sleep disturbance and impaired executive function is well- established, and the effects of sleep loss on executive function may have negative downstream consequences for emotional processes. Indeed, decreased executive function is linked to maladaptive repetitive thought (Segerstrom, Roach, Evans, Schipper, & Darville, 2010), and specific dimensions of executive function are linked to worry and rumination. These findings suggest that deficits in executive function may diminish cognitive control over emotional processes, which may lead to increased engagement in worry and rumination.
Although the respective relationships between sleep, executive function, and the maladaptive repetitive thought that characterizes many anxiety-related disorders is well- established, no study to date has assessed the role of executive function in the relationship between sleep disturbance and maladaptive repetitive thought. Accordingly, the present study employed structural equation modeling (SEM) to examine executive function as a potential intervening variable in the relationship between sleep problems and maladaptive repetitive thought, specifically worry and rumination. It was predicted that increased sleep disturbance would be associated with increased levels of maladaptive repetitive thought, and this relationship would be accounted for by increased impairments in executive function.
Such relevant confounds include nonspecific third variables that may be related to sleep disturbance and maladaptive repetitive thought. Indeed, aspects of distress, such as depression, stress, and distress tolerance, are broadly associated with sleep disturbance and maladaptive repetitive thought (Buysse et al., 2008; Minkel et al., 2014; Huang, Szabo, & Han, 2009; Morrison & O’Connor, 2005). Accordingly, general distress was included as a rival factor in the model to assess whether executive function accounted for the relationship between sleep disturbance and maladaptive repetitive thought above and beyond the effect of general distress.
Method
Review and approval for this study and all procedures was obtained from the Vanderbilt University Institutional Review Board, and informed consent was obtained from all individual participants included in the study. Items on the ACS are rated on a Likert scale from 1 (almost never) to 4 (always), and higher scores indicate better attentional control. In the present sample, the ACS Focusing and Shifting subscales had adequate internal consistency (α = .83 and α = .80, respectively).
Items on the DASS are rated on a Likert scale from 0 (did not apply to me at all) to 3 (applied to me very much, or most of the time), and higher scores indicate higher degrees. In the present sample, the Depression and Stress subscales had adequate internal consistency (α = .89 and α = .89, respectively). Items on the DTS are rated on a Likert scale from 1 (strongly agree) to 5 (strongly disagree), and higher scores.
Items on the ISI are rated on a Likert scale from 1 (none) to 4 (very severe), and higher scores indicate a higher severity of insomnia. The PSQI is a 19-item self-report measure of sleep quality and sleep disturbance over the past month. Items are rated on a Likert scale from 1 (not at all typical of me) to 5 (very typical of me), and higher scores indicate an increased tendency to worry.
Items are rated on a Likert scale from 1 (strongly disagree) to 5 (strongly agree), and higher scores indicate an increased tendency to ruminate. Items are rated on a Likert scale from 1 (no problems experienced) to 4 (a great many problems experienced), and higher scores. Maladaptive Repetitive Thought (i.e., that the direct path drops to 0 upon including the intervening variables in the model).
Results
Second, we examined the significance of the indirect (intervening) pathways through the two proposed intervening variables and both pathways were significant (see Figure 2). We then conducted the chi-square difference test between the constrained model. whereby the direct path was constrained to 0) and the freed model (whereby the direct path was freely estimated). The non-significance of this difference supports the notion that the intervening variables fully account for the association between Sleep Disturbance and Maladaptive Repetitive Thought.
Together, the causal link test, the test of indirect effects via the mediators, and the Scaled Difference of the Satorra-Bentler Scaled Chi-Square test supported the proposition that. Executive Function and Distress fully account for the relationship between Sleep Disturbance and Maladaptive Repetitive Thought. To test for gender differences in the extent to which intervening variables fully account for the association between Sleep Disturbance and Maladaptive Repetitive Thought, we re- conducted all analyses based on the female-only subsample (n = 278) and the male-only subsample (n = 63).
Results were identical in the female-only and male-only subsamples, including both intervening variables being associated with significant indirect effects in both subsamples. Distress fully account for the association between Sleep Disturbance and Maladaptive Repetitive Thought in both males and females.
Discussion
Drawing from the available literature, it was hypothesized that deficits in executive function may account for the association between sleep disturbance and excessive worry and rumination. To assess the specificity of executive function in the relationship between sleep disturbance and maladaptive repetitive thought, it is critical to control for as many relevant confounds as is practical. More specifically, the present study highlights deficits in executive function as a potential mechanism by which sleep disturbance may confer risk for increased engagement in maladaptive repetitive thought.
However, the present results provide preliminary evidence for the role of executive function as a candidate mechanism that may link sleep disturbance and maladaptive repetitive thought and suggest that future. Based on this finding, addressing subjective sleep disturbance may aid in the treatment of maladaptive repetitive thought. Further, these results suggest that interventions aimed at enhancing executive function may be useful for the reduction of maladaptive repetitive thought in individuals with sleep disturbance (Cohen, Mor, & Henik, 2015; Diamond & Lee, 2011).
Future research addressing the downstream effects of sleep disturbance on cognitive and emotional function is necessary to further explore this pathway and delineate the role of executive function in the relationship between sleep and maladaptive repetitive thought. The present study examined the unique relationship between sleep disturbance and anxiety-related symptoms, as well as one potential mechanism by which sleep disturbance may contribute to anxiety-related symptoms. Study two found that executive function partially accounted for the relationship between sleep disturbance and maladaptive repetitive thought over and above the effect of general distress.
Further, the present findings indicate that executive function may be one mechanism by which sleep disturbance contributes to anxiety-related symptoms. The evidence for links between sleep disturbance and OCS, worry, and rumination suggest that sleep disturbance may be an important factor in the. The results of these studies also indicate that the link between sleep disturbance and anxiety-related symptoms is not accounted for by depression or depressive symptoms.
Finally, the results of study two offer preliminary evidence for the role of executive function in the relationship between sleep disturbance and anxiety-related symptoms. The relationship between sleep disturbance and the course of anxiety disorders in primary care patients.
