Subjective sleep disturbances are associated with intrinsic motivation toward sleep-related thinking

Sleep-related attentional and interpretive-bias in insomnia: A systematic review and meta-analysis

Cognitive models of insomnia highlight internal and external cognitive-biases for sleep-related "threat" in maintaining the disorder. This systematic review of the sleep-related attentional and interpretive-bias literature includes meta-analytic calculations of each construct. Searches identified N = 21 attentional-bias and N = 8 interpretive-bias studies meeting the inclusion/exclusion criteria. Seventeen attentional-bias studies compared normal-sleepers and poor-sleepers/insomnia patients. Using a random effects model, meta-analytic data based on standardized mean differences of attentional-bias studies determined the weighted pooled effect size to be moderate at 0.60 (95%CI:0.26-0.93). Likewise, seven of eight interpretive-bias studies involved group comparisons. Meta-analytic data determined the weighted pooled effect size as moderate at .44 (95%CI:0.19-0.69). Considering these outcomes, disorder congruent cognitive-biases appear to be a key feature of insomnia. Despite statistical support, absence of longitudinal data limits causal inference concerning the relative role cognitive-biases in the development and maintenance of insomnia. Methodological factors pertaining to task design, sample and stimuli are discussed in relation to outcome variation. Finally, we discuss the next steps in advancing the understanding of sleep-related biases in insomnia.

Sleep-related monitoring on awakening mediates the relationship between insomnia-related interpretive bias and insomnia symptoms using the insomnia ambiguity paradigm

A number of studies have examined and confirmed the presence of a sleep-related interpretive bias amongst poor sleepers and individuals with insomnia using an insomnia ambiguity task. This study explored possible mechanisms underlying the relationship between interpretive bias and insomnia using the insomnia ambiguity task. More importantly, the possible mediating role of sleep-associated monitoring, sleep preoccupation, sleep anticipatory anxiety and generalized anxiety was also examined. A total of N = 176 participants were stratified into normal sleepers and those displaying insomnia symptoms. Participants completed an online version of the insomnia ambiguity task and questionnaire measures pertaining to sleep and anxiety. Data concerning task response time and time of testing were also collected. Individuals in the insomnia symptom group presented significantly higher sleep-related interpretive bias scores compared to normal sleepers. When sleepiness, sleep-associated monitoring, sleep preoccupation, sleep anticipatory anxiety and generalized anxiety were controlled for, only monitoring on awakening predicted sleep-related interpretive bias. Multiple mediation modelling demonstrated that sleep-associated monitoring on awakening mediated the relationship between interpretive bias and insomnia symptoms. The current outcomes are consistent with previous research, supporting the notion that insomnia is characterized by a disorder-consistent interpretive bias. Furthermore, monitoring for insomnia-consistent cues on awakening appears to mediate group differences in interpretive bias.

Misperception of sleep is associated with intrinsic motivation toward thinking about sleep

BACKGROUND AND OBJECTIVES

Misperception of sleep, the underestimation of total sleep time and overestimation of sleep onset latency (SOL) relative to objective measures, is often found in people with sleep disturbances. Theories of insomnia have proposed that perceived sleeplessness triggers excessive intention and effort to sleep, ironically disturbing the normal initiation of sleep. The current study tested this specific association between (mis)perception of sleep and intrinsic motivation to think about sleep.

METHODS

The sample (n = 74) covered students and community living in Munich and surrounds with ages between 18 and 30 years. We assessed the subjective and objective sleep of participants using a sleep diary and actigraphy. Participants also completed a decision-making task (the pay-per-view task), where they had to decide between thinking about sleep vs. eating. As these options were associated with a variable monetary reward, participants typically experienced a conflict between their preferred topic and the reward for their choice.

RESULTS

Multilevel logistic regression analyses showed that participants with greater SOL misperception (i.e., longer subjective relative to objective SOL) forgo a greater reward for the opportunity to think about sleep.

LIMITATIONS

The non-clinical nature of our sample may limit the implication of the findings for clinical levels of insomnia.

CONCLUSIONS

Results support the cognitive model of insomnia, suggesting that perception of sleeplessness is associated with higher intrinsic motivation to engage in sleep-related thinking.

Pre-sleep arousal can be associated with efficient processing of sleep-related information

BACKGROUND AND OBJECTIVES

Cognitive bias to sleep-related information is thought to be a core feature of sleep disturbances. The bias may enhance pre-sleep arousal, such as excessive worry about sleeplessness, which prevents people from initiating normal sleep onset. The present study focused on (a) attention bias toward sleep-related stimuli and (b) difficulty in updating working memory for sleep-related stimuli as two possible mechanisms underlying pre-sleep cognitive arousal.

METHOD

Participants (n = 61, a community sample) completed a dot-probe task (with sleep-related and matched control word stimuli) and a 1-back and 2-back task (with sleep-related and non-sleep-related pictorial stimuli).

RESULTS

For the dot-probe task, the results showed no significant association between pre-sleep cognitive arousal and sleep-related attention bias. However, the results of the 2-back task suggest that pre-sleep arousal is associated with decreased interference by sleep-related stimuli in maintaining non-sleep-related information. That is, individuals with higher levels of pre-sleep arousal are more efficient at processing sleep-related materials.

LIMITATIONS

The non-clinical nature of the sample may limit the clinical implications of the findings.

CONCLUSIONS

Although the current results cannot be explained by the extant cognitive theories of insomnia, we offer an alternative explanation based on the idea of worry as mental habit: mental processes that occur frequently (e.g., repetitive thoughts about sleep) require less cognitive resource. Therefore, sleep-related information may be processed easily without consuming much cognitive effort.