Disrupted sleep moderates the association between Psychotic-like Experiences and Working Memory in Young Adults.

Isla Tsz Kwan, Forrest Tin Wai Cheung, Shirley Xin Li

Abstract

Introduction: Psychotic-like Experiences (PLEs) refer to psychotic symptoms in a subclinical population. Individuals with PLEs (e.g., increased bizarre experiences) were found to have cognitive deficits, such as low working memory capacity. Although growing literature has suggested the negative effects of sleep disturbances on cognitive functioning, it remains unclear whether poor sleep would exacerbate cognitive problems in people with PLEs. The current study aimed to examine the moderating effect of sleep on the association between PLEs and working memory in young adults.

Methods: A total of 64 university students (age = 19.21 ± 1.5, % female = 76.6) were included in the analyses. Participants were free of any psychiatric disorders as ascertained by Mini International Neuropsychiatric Interview (MINI). They completed the Community Assessment of Psychic Experiences (CAPE) as a measure of PLEs, the Insomnia Severity Index (ISI) and Pittsburgh Sleep Quality Index (PSQI) as measures of self-perceived sleep quality, and 8-day actigraphy sleep monitoring, followed by a laboratory-based assessment using a computerized n-back task and digit span task to measure working memory. Weighted d prime (d’), which considered both hit and false alarm rates, was used to reflect the accuracy, while Response time (RT) was calculated for only correct responses in the n-back task. Sleep onset latency (SOL), wake after sleep onset (WASO), total sleep time (TST), and sleep efficiency (SE) were derived from sleep diary and actigraphy for analyses. Hayes’ PROCESS Macro version 4.0 was used to test the moderating effect of sleep on the association between PLEs and working memory performance.

Results: Total PLEs were associated with n-back RT at a marginal significance (B = -1.60, p = .057). Moderation analyses indicated that most sleep parameters significantly moderated in the association between total PLEs and n-back RT. These included WASO measured by both actigraphy (B = -.157, p = .002) and sleep diary (B = .669, p = .014), sleep diary measured by SOL (B = .416, p = .003), as well as TST (B = .040, p = .011) and SE (B = .400, p = .005) measured by actigraphy. Self-reported sleep quality (PSQI, B=-.556, p=.510) and insomnia symptoms (ISI, B=-.177, p=.536) and other parameters from sleep dairy and actigraphy did not significantly moderate the association between PLEs and n-back RT. No significant associations was found between PLEs and the performance on digit span task.

Conclusion: The findings of the present study provided preliminary support for the moderating effect of sleep on the relationship between PLEs and working memory. Future studies should include a larger sample size and utilize a longitudinal design to examine the causality of these associations. The findings also implied the potential need for timely assessing and addressing disrupted sleep in vulnerable young adults, especially those with PLEs.

Recommended citation: Hui, T. K., Cheung, F. T. W., & Li, S. X. (2022). Disrupted sleep moderates the association between Psychotic-like Experiences and Working Memory in Young Adults. Sleep Medicine, 100, S145.