Testing the contiguity of the sleep and fatigue relationship: a daily diary study.

STUDY OBJECTIVES: There is mixed evidence for the relationship between poor sleep and daytime fatigue, and some have suggested that fatigue is simply caused by lack of sleep. Although retrospective measures of insomnia and fatigue tend to correlate, other studies fail to demonstrate a link between objectively disturbed sleep and fatigue. The current study prospectively explored the relationship between sleep and fatigue among those with and without insomnia disorder. METHODS: Participants meeting Research Diagnostic Criteria for insomnia disorder (n = 33) or normal sleepers (n = 32) completed the Consensus Sleep Diary (CSD) and daily fatigue ratings for 2 weeks. Baseline questionnaires evaluated cognitive factors including unhelpful beliefs about sleep and rumination about fatigue. Hierarchical linear modeling tested the within- and between-participant relationships between sleep quality, total sleep time, and daily fatigue ratings. Mediation analyses tested if cognitive factors mediated the relationship between insomnia and fatigue. RESULTS: Self-reported nightly sleep quality significantly predicted subsequent daily fatigue ratings. Total sleep time was a significant predictor of fatigue within, but not between, participants. Unhelpful sleep beliefs and rumination about fatigue mediated the relationship between insomnia and fatigue reporting. CONCLUSIONS: The results suggest that perception of sleep plays an important role in predicting reports of daytime fatigue. These findings could be used in treatment to help shift the focus away from total sleep times, and instead, focus on challenging maladaptive sleep-related cognitions to change fatigue perception.

Is daily routine important for sleep? An investigation of social rhythms in a clinical insomnia population.

Social rhythms, also known as daily routines (e.g. exercise, of school or work, recreation, social activities), have been identified as potential time cues to help to regulate the biological clock. Past research has shown links between regularity and healthy sleep. This study examined the regularity and frequency of daytime activities in a clinical insomnia population and a good sleeper comparison group. Participants (N = 69) prospectively monitored their sleep and daily activities for a 2-week period. Although participants with insomnia and good sleepers had similar levels of activity, relative to good sleepers, those with insomnia were less regular in their activities. Findings from this study add to the growing number of studies that highlight the relative importance of the regularity of daytime activities on sleep. Accordingly, future research should test treatment components that focus on regulating daytime activities, which would likely improve treatment outcomes.

The relation between insomnia symptoms, mood, and rumination about insomnia symptoms.

STUDY OBJECTIVES: Research suggests that rumination may play an important role in insomnia. Whereas some have suggested that rumination mainly relates to depression, the evidence suggests that there may be insomnia-specific rumination. This paper explores insomnia symptom rumination across two distinct samples of varying levels of depressed mood and insomnia symptom severity. METHODS: The first sample consisted of nonclinical participants (N = 327) with a range of insomnia and depressed mood symptoms, and the second sample consisted of those who met both Major Depressive Disorder and Insomnia diagnoses (N = 66). Rather than relying on a measure developed for those with depression, we developed and tested an insomnia-specific measurement scale based on items from previous rumination studies and the addition of items derived from common daytime insomnia symptoms. RESULTS: Internal consistency was highly acceptable across the two samples for the new insomnia-specific rumination measure (Cronbach α was 0.93 and 0.94). In the first study, poor sleepers reported significantly higher levels of daytime symptom rumination than did good sleepers. Across both studies, rumination about daytime insomnia symptoms and depression were significantly correlated; however, insomnia rumination scores predicted insomnia even after controlling for depression. Moreover, in Study 2, insomnia-specific rumination was related to insomnia, but general depressive rumination was not predictive of insomnia. CONCLUSIONS: The findings provide support for the use of this insomnia-specific rumination scale; moreover the findings support previous observances regarding rumination about daytime insomnia symptoms that are not exclusive to depression.

Can we modify maladaptive attributions for fatigue?

Research has shown that those with insomnia focus primarily on their sleep as a cause of daytime fatigue rather than the multitude of other possible causes of fatigue. This can create sleep-related anxiety and further perpetuate the sleep disturbance. In order to lessen the increased focus on sleep, the present study investigated whether people could learn to consider other attributions for fatigue via an information-based manipulation. Undergraduate students (N = 88) were randomized to two information groups: They either received information about common factors that could explain daytime fatigue (the fatigue information condition) or received generic sleep-related information (the control condition). Each group was tested pre- and post-intervention. Fatigue information participants were significantly more likely to consider non-sleep-related attributions for fatigue at post-intervention, relative to control participants. These results demonstrate that attributions for fatigue may be amenable to change via an information-based intervention; thus, this research explores a preliminary step toward investigating refinements to insomnia treatments.

Rethinking safety behaviors in insomnia: examining the perceived utility of sleep-related safety behaviors.

Harvey's cognitive model of insomnia (2002a) proposes that sleep-related safety behaviors play a central role in the maintenance of insomnia because such maladaptive coping strategies are thought to reinforce threat-based appraisals of the likelihood and consequences of poor sleep. Research to date has assessed the frequency of safety behavior use in those with insomnia only; however, in addition to the frequency of occurrence, the function of safety behaviors (i.e., a belief that they will prevent a feared outcome from occurring), may be an important consideration. The purpose of this study was to examine sleep-related safety behaviors based on an expanded theoretical understanding of such behaviors across psychological disorders; that is, by examining both their frequency and perceived utility. Undergraduate students (N=376) completed an online survey about their sleep, mood, and use of sleep-related safety behaviors. Insomnia severity was associated with a greater perceived need to use safety behaviors (i.e., utility) but not with frequency of safety behavior use. Higher perceived utility of safety behaviors was also associated with unhelpful beliefs about sleep, fear and avoidance of fatigue, and both general and sleep-specific helplessness. These results suggest that these behaviors and the associated underlying maladaptive beliefs may be important targets in cognitive behavioral therapy for insomnia. The current study extends the existing literature and refines the concept of safety behaviors in insomnia to include both the function and frequency of these behaviors.

Should we be anxious when assessing anxiety using the Beck Anxiety Inventory in clinical insomnia patients?

Assessing for clinical levels of anxiety is crucial, as comorbid insomnias far outnumber primary insomnias (PI). Such assessment is complex since those with Anxiety Disorders (AD) and those with PI have overlapping symptoms. Because of this overlap, we need studies that examine the assessment of anxiety in clinical insomnia groups. Participants (N = 207) were classified as having insomnia: 1) without an anxiety disorder (I-ND), or 2) with an anxiety disorder (I-AD). Mean Beck Anxiety Inventory (BAI) item responses were compared using multivariate analysis of variance (MANOVA) and follow-up ANOVAs. As a validity check, a receiver operating characteristic (ROC) curve analysis was conducted to determine if the BAI suggested clinical cutoff was valid for identifying clinical levels of anxiety in this comorbid patient group. The I-ND had lower mean BAI scores than I-AD. There were significant group differences on 12 BAI items. The ROC curve analysis revealed the suggested BAI cutoff (≥16) had 55% sensitivity and 78% specificity. Although anxiety scores were highest in those with insomnia and an anxiety disorder, those with insomnia only had scores in the mild range for anxiety. Nine items did not distinguish between those insomnia sufferers with and without an anxiety disorder. Additionally, published cutoffs for the BAI were not optimal for identifying anxiety disorders in those with insomnia. Such limitations must be considered before using this measure in insomnia patient groups. In addition, the poor specificity and high number of overlapping symptoms between insomnia and anxiety highlight the diagnostic challenges facing clinicians.

Residual sleep beliefs and sleep disturbance following Cognitive Behavioral Therapy for major depression.

BACKGROUND: Sleep disturbance is a commonly reported residual symptom after effective depression treatment. This residual sleep impairment, as well as the presence of problem levels of certain sleep beliefs, may be important for depressive relapse prevention, and as such should be addressed in treatment. The following study examined residual sleep disturbance and residual maladaptive sleep beliefs in those treated with Cognitive Behavior Therapy for depression. METHODS: Participants (N = 24) were clinic patients seeking treatment for depression at a community clinic. Repeated measures analyses of variance tested pre- to posttreatment change on depression symptoms, general negative beliefs, sleep quality, and maladaptive sleep beliefs. RESULTS: As expected, significant time effects were found for depressive symptoms and general negative beliefs. Sleep quality scores also decreased significantly at posttreatment; however, 92% of those no longer meeting depressive criteria continued to endorse residual sleep disturbance, according to an established clinical cutoff score of > 5 on a validated measure of sleep quality (the Pittsburgh Sleep Quality Index). There were no significant pre- to posttreatment changes for maladaptive sleep beliefs. CONCLUSIONS: The results indicate that sleep disturbance and maladaptive sleep-related beliefs remain a problematic residual symptom of remitted depression. These findings are discussed with reference to improving cognitive behavioral treatments for depression in order to help reduce rates of residual sleep problems.

Distinguishing rumination from worry in clinical insomnia.

Research has found that repetitive thought processes, such as worry and rumination, play an important role in several disorders; however, these cognitive processes have not yet been examined in insomnia. This study explores rumination and worry in insomnia by examining: 1) whether those high and low on rumination and worry differ on subjective sleep measures, and 2) whether rumination and worry are distinct processes in insomnia. Participants (N=242) were diagnosed with an insomnia disorder by sleep experts. Participants completed measures of worry and rumination and maintained a 2-week daily sleep log. Results of a multivariate analysis of variance found no main effect of worry; although high and low ruminators differed on several sleep log indices, including sleep efficiency, wakefulness after sleep onset and sleep quality. Factor analysis supported the idea that rumination and worry are separate constructs. Whereas previous research has focused on worry in insomnia, these findings suggest that rumination is important for understanding sleep disturbance. Further, although rumination and worry are both repetitive thought processes, these results indicate that they are distinct processes within insomnia and should be treated as such. The results are discussed with respect to treatment implications for Cognitive Behavioural Therapy for Insomnia.