582 Insomnia-related cognitive and behavioural factors in adolescents with delayed sleep-wake phase disorder

Abstract

Abstract Introduction Although delayed sleep-wake phase disorder (DSWPD) shares phenomenological experiences with chronic insomnia disorder, previous research on the conceptual understanding of DSWPD has been limited, with a predominant focus on its chronobiological basis. The present study examined several insomnia-related cognitive and behavioural factors in adolescents with DSWPD. Methods Twenty-five adolescents with DSWPD (age = 19.9 ± 1.6; female = 28%), 28 with chronic insomnia disorder (age = 20.4 ± 2.0; female = 61%), diagnosed according to the ICSD-3 criteria, and 25 healthy control (age = 20.4 ± 1.5; female = 68%) were included in the present study. Participants completed 7-day prospective sleep diary and actigraphy monitoring, and a battery of questionnaires on sleep and chronotype measures. Participants were also measured on hyperarousal (Pre-Sleep Arousal Scale, PSAS), sleep reactivity (Ford Insomnia Response to Stress Test, FIRST), sleep-related beliefs (Dysfunctional Beliefs and Attitudes about Sleep, DBAS-16), and sleep hygiene practices (Sleep Hygiene Practices Scale, SHPS). Analysis of covariance (ANCOVA) with gender as the covariate was used for between-group comparisons. Results Relative to healthy control group, insomnia and DSWPD group showed significantly more insomnia symptoms as measured by Insomnia Severity Index (p<.001). As compared to healthy control group, DSWPD group showed significantly more delay in circadian phase based on sleep diary and actigraphy derived mid-point of sleep, as well as greater preference towards eveningness as measured by the Morningness-Eveningness Questionnaire. DSWPD group also showed significantly more cognitive and somatic hyperarousal (p<.001, d = 1.36–2.31), sleep reactivity (p<.001, d = 1.73), dysfunctional belief about sleep (p<.001, d = 1.59), as well as poorer sleep hygiene practices (p<.001, d = 2.62), compared to healthy control. There were no significant differences in the circadian parameters, PSAS, FIRST, DBAS-16, and SHPS between DSWPD and insomnia groups. Conclusion Several insomnia-related cognitive and behavioural factors, namely hyperarousal, sleep reactivity, maladaptive beliefs about sleep, and poor sleep hygiene, are also evident in youths with DSWPD. The findings had important implications for the conceptual understanding and clinical management of DSWPD. Support (if any) This work was supported by the Seed Fund for Basic Research (University Research Committee, The University of Hong Kong) awarded to Dr. Shirley Li.