Rebecca C. Cox

A systematic review of sleep disturbance in anxiety and related disorders

Recent research suggests that sleep disturbance may be a transdiagnostic process, and there is increasing interest in examining how sleep disturbance may contribute to anxiety and related disorders. The current review summarizes and synthesizes the extant research assessing sleep in anxiety and related disorders. The findings suggest that sleep disturbance exacerbates symptom severity in the majority of anxiety and related disorders. However, the nature of sleep disturbance often varies as a function of objective versus subjective assessment. Although sleep disturbance is a correlate of most anxiety and related disorders, a causal role for sleep disturbance is less clear. A model of potential mechanisms by which sleep disturbance may confer risk for the development of anxiety and related disorders is discussed. Future research integrating findings from basic sleep research with current knowledge of anxiety and related disorders may facilitate the development of novel treatments for comorbid sleep disturbance and clinical anxiety.

Sleep Disturbance in Posttraumatic Stress Disorder: Epiphenomenon or Causal Factor?

Purpose of ReviewThe goal of this review is to integrate recent findings on sleep disturbance and PTSD, examine sleep disturbance as a causal factor in the development of PTSD, and identify future directions for research, treatment, and prevention.Recent FindingsRecent research highlights a relationship between both objective and subjective sleep disturbance and PTSD across diverse samples. Sleep disturbance also predicts PTSD over time. Finally, treatments targeting sleep disturbance lead to decreased PTSD symptoms, while standard PTSD treatments conclude with residual sleep disturbance.SummarySleep disturbance may be more than a mere epiphenomenon of PTSD. Future research examining the causal role of sleep disturbance in the development of PTSD, as well as the utility of targeting sleep disturbance in prevention and treatment, is necessary to fully understand the likely bidirectional relationship between sleep disturbance and PTSD.

Sleep disturbance and obsessive-compulsive symptoms: Results from the national comorbidity survey replication

A small body of developing research has found evidence for sleep disturbance in obsessive-compulsive disorder (OCD) and links between sleep disturbance and obsessive-compulsive symptoms (OCS) in unselected samples. However, the link between sleep disturbance and OCS is yet to be examined in a nationally representative sample. Furthermore, the extent to which the link between sleep disturbance and OCS is accounted for by symptoms of depression remains unclear. To address this gap in the literature, the present study examined the relationship between sleep disturbance and OCS in a nationally representative sample. Participants were assessed in the National Comorbidity Survey Replication (NCS-R; n = 2073). Consistent with predictions, results revealed that individuals with sleep disturbance reported increased OCS severity compared to individuals without sleep disturbance. Further, sleep disturbance severity was associated with OCS severity, even when controlling for depression (and other anxiety-related disorders). This study is the first to link sleep disturbance and OCS in a nationally representative sample, and these findings highlight the unique role of sleep disturbance in the experience of OCS. Future research is necessary to delineate specific mechanisms that may account for this relationship.

Effects of Experienced Disgust on Morally-Relevant Judgments

Although disgust has been implicated in moral judgments, the extent to which the influence of disgust on moral judgment is distinct from other negative affective states remains unclear. To address this gap in knowledge, participants in Study 1 were randomized to a disgust (hand submersion in imitation vomit), discomfort (hand submersion in ice water), or neutral (hand submersion in room temperature water) affect condition while moral judgments of offenses were simultaneously assessed. The results showed that participants in the discomfort condition made the most severe moral judgments, particularly for moderate offenses. To examine if disgust may have more of an effect on some moral violations than others, participants in Study 2 were randomized to similar affect inductions while judgments of purity and non-purity offenses were simultaneously assessed. The results showed that those who had their hand submerged in imitation vomit recommended harsher punishment for purity violations relative to moral violations unrelated to purity. The opposite was true for those who submerged their hands in ice water, whereas punishment ratings for purity and non-purity violations did not significantly differ for those who submerged their hands in room temperature water. The implications of these findings for further delineating the specific role of experienced disgust in moral decision-making are discussed.

Prospective Associations Between Sleep Disturbance and Repetitive Negative Thinking: The Mediating Roles of Focusing and Shifting Attentional Control

Although considerable evidence has linked sleep disturbance to symptoms of psychopathology, including repetitive negative thinking, few studies have examined how sleep disturbance may predict repetitive negative thinking over time. Further, no study to date has examined specific mechanisms that may account for this relationship. The present study sought to address these gaps in the literature by testing focusing and shifting attentional control as two potential mediators of the relationship between sleep disturbance and repetitive negative thinking over a 6-month period. A final sample of 445 unselected community participants completed measures of sleep disturbance and repetitive negative thinking at Time 1, measures of focusing and shifting attentional control 3 months later, and measures of repetitive negative thinking again 6 months later. Results revealed that focusing, but not shifting, attentional control mediated the relationship between sleep disturbance and repetitive negative thinking, specifically, worry, rumination, and obsessions. These findings provide preliminary evidence for focusing attentional control as a candidate mechanism that may explain the causal role of sleep disturbance in the development of repetitive negative thinking observed in various disorders.

Cognitive mechanisms of disgust in the development and maintenance of psychopathology: A qualitative review and synthesis

A growing body of research has implicated disgust in various psychopathologies, especially anxiety-related disorders. Although the observed role of disgust in many disorders is robust, the mechanisms that may explain this role are unclear. Cutting-edge research in cognitive science has the potential to elucidate such mechanisms and consequently improve our understanding of how disgust contributes to the etiology and maintenance of psychopathology. In this qualitative review, we systematically assess cognitive bias mechanisms that have been linked to disgust and its disorders. This review suggests that disgust-related biases may be observed in memory, interpretation, judgment of expectancies, and attention, as well as at implicit levels. Of these cognitive domains, the most robust bias appears to be observed at the level of attention. However, reliable moderators of attentional biases for disgust have not yet been identified, and this bias has not been systematically linked to other levels of analysis. Despite these limitations, the available research indicates that attentional avoidance rather than orienting or maintenance may be the most characteristic of disgust. Attentional avoidance of disgust may have important implications for etiological and treatment models of disorders characterized by excessive disgust reactions. The implications for advancing such models are discussed in the context of a combined cognitive bias hypothesis.

The effects of cognitive reappraisal on conditioned disgust in contamination-based OCD: An analogue study

Experimental research has shown that conditioned disgust is resistant to extinction, which may account for the slower habituation to disgust relative to fear in contamination-based obsessive-compulsive disorder (OCD). However, few studies have examined the efficacy of interventions that may attenuate conditioned disgust responses. Studies of cognitive reappraisal have demonstrated that reinterpreting a stimulus can alter emotional responding. This technique is based on cognitive theories which suggest that anxiety disorders arise from biased cognitions; therefore, changing a persons thoughts will elicit durable changes in emotional responses. Given the demonstrated effectiveness of cognitive reappraisal, the present study examined whether cognitive reappraisal would attenuate conditioned disgust responses. We conditioned participants high in contamination fear (n=55) using images of neutral food items (conditioned stimuli; CS) paired with videos of individuals vomiting (unconditioned stimuli; US) while we obtained subjective disgust reports. After conditioning, half of the participants were randomly assigned to cognitive reappraisal training aimed at decreasing their emotional response to the US and CS, while the other half received no such training. The findings showed that cognitive reappraisal participants demonstrated a reduction in learned disgust across sessions and further benefited from extinction. These findings suggest that cognitive reappraisal may be an effective strategy for attenuating learned disgust.

Linking attentional control and PTSD symptom severity: the role of rumination

Abstract Although deficits in attentional control have been linked to posttraumatic stress disorder (PTSD), the mechanism that may account for this association has not been fully elucidated. The present study examined rumination as a mediator of the relationship between attentional control and PTSD symptoms. Veterans with PTSD and trauma-exposed veterans without PTSD completed measures of attentional control, rumination, and PTSD symptom severity. As predicted, the findings showed that veterans with PTSD reported significantly lower levels of attentional control than veterans without PTSD. Veterans with PTSD also reported significantly higher levels of rumination than veterans without PTSD. Subsequent analysis of the total sample revealed that the relationship between attentional control and PTSD symptom severity was accounted for by excessive rumination. Attentional control may contribute to PTSD symptoms through excessive rumination. Attentional control and rumination may be important targets for PTSD interventions.

The role of eveningness in obsessive-compulsive symptoms: Cross-sectional and prospective approaches

BACKGROUND Eveningness may be defined as the tendency to be most active and alert during the evening. Previous research has linked eveningness with maladaptive psychological outcomes, and recent evidence has highlighted circadian dysregulation as a novel factor in psychopathology, including obsessive-compulsive disorder (OCD). However, limited research has examined the unique relationship between eveningness and OC symptoms. Two studies were conducted to thoroughly examine the links between eveningness and OC symptoms, while also considering the role of depression symptoms and sleep-related factors. METHODS Using a cross-sectional approach, Study 1 examined the association between eveningness and OC symptoms when controlling for depression symptoms. Study 2 then employed a prospective approach to examine the extent to which the relationship between eveningness and change in OC symptoms over 4 months is mediated by change in sleep disturbance and total sleep time when controlling for depression symptoms. RESULTS Results indicated that depression better accounts for the cross-sectional association between eveningness and OC symptoms. However, eveningness was found to be a more robust prospective predictor of change in OC symptoms in Study 2. Furthermore, sleep disturbance, but not total sleep time, partially mediated the relationship between eveningness and OC symptoms. LIMITATIONS Single-method self-report approach, unselected sample, and lack of experimental manipulation. CONCLUSIONS These findings suggest that eveningness may contribute to the development of OC symptoms over time, in part due to its effect on sleep disturbance. Future research examining the role of circadian dysregulation in OCD may uncover novel physiological mechanisms.

Sleep Disturbance in Obsessive-Compulsive Disorder: Preliminary Evidence for a Mechanistic Relationship

Purpose of ReviewSleep disturbance has received growing attention as a transdiagnostic factor that may contribute to multiple forms of psychopathology, including obsessive-compulsive disorder (OCD). The extant literature regarding the role of sleep disturbance in OCD is rapidly developing. This review integrates the findings related to sleep and OCD over the past year and highlights important areas for future research.Recent FindingsResults indicate impaired sleep in those with OCD versus healthy controls and link sleep disturbance to OCD symptom severity in multiple samples. Findings from the past year also implicate cognitive control as a potential mechanism in this relationship. Finally, a recent treatment outcome study suggests that sleep disturbance may limit treatment response in pediatric OCD.SummaryFindings from the past year contribute to the robustness of the small, but growing body of literature linking sleep disturbance to OCD. These results highlight the importance of incorporating sleep disturbance into extant models of OCD and suggest that consideration of the biopsychosocial effects of sleep disturbance may offer novel insight into the etiology and treatment of OCD.