A study of Cognitive Disengagement Syndrome, sleep and everyday functioning in adults

Abstract

Cognitive Disengagement Syndrome (CDS) symptoms manifest as sluggishness, mind wandering, withdrawal and brain fog. Previously studied as part of ADHD, CDS is now regarded as a separate construct, with both conditions still sharing around 30 % of variance. There are few meta-analyses in the CDS literature and limited studies on adult samples examining the relationship between CDS and psychopathologies such as sleep, daytime sleepiness and executive function. This thesis sought to explore these relationships to consolidate and expand the evidence base. A systematic review was conducted, 14 studies were included examining associations between CDS and poor sleep, daytime sleepiness and circadian preference. Overall, 13 studies were included for numerical synthesis, and one was reported narratively. Moderate significant associations were found between CDS and poor sleep (r = 0.42 CI [0.33,0.49], k = 13, N = 3,456), CDS and daytime sleepiness (r = 0.38, CI [0.31,0.44], k =3, N = 616) and CDS and evening preference (r = -0.31, CIs [ -0.38, -0.24] k= 3, N =618). The review established that few adult studies have examined the relationship, as most were conducted in young student populations (k = 9), and many studies were conducted in the context of ADHD (k= 7). The significant moderate effects suggest that a relationship between CDS and sleep exists, however the meta-analytical findings could not ascertain whether this association was bidirectional. The empirical study aimed to examine this potential bidirectional relationship, and whether variables such as daytime sleepiness and executive function impacted the association. Using Hayes’ PROCESS macro (models 14 and 15), we carried out conditional process analyses to test the hypotheses, predicting a bidirectional relationship between poor sleep and CDS, mediated by daytime sleepiness and moderated by executive function in a community adult sample (N= 453). Significant direct effects between poor sleep on CDS, and CDS on poor sleep were found, significantly mediated by daytime sleepiness at the indirect path. There were non significant findings for both the moderated sleep by executive function interaction and the concentration by executive function interaction. The mediating effects of sleepiness on the indirect pathway of poor sleep and CDS became non-significant when controlling for ADHD symptoms. The significant effects observed in the other pathways remained significant though weakened when controlling for depression and ADHD. These findings warrant further investigation. The results from this review and empirical study highlight the need for future longitudinal research to explore the CDS and sleep association across multiple timepoints to test the inferences drawn from cross-sectional studies such as the current study, to test possible causal pathways. Further exploration is required to examine the mechanisms underpinning the impact of evening preference on CDS and depression, and links with daily dysfunction. Given the impact of ADHD on the indirect relationship between sleep and CDS mediated by sleepiness, future research could examine the nuances of CDS sub-components and association with sleep. This could lead to potentially useful interventions targeting mood, ADHD and daytime sleepiness to address both poor sleep and symptoms of poor concentration