Preoccupation with sleep and dysfunctional beliefs about sleep mediate the influence of psychological inflexibility on insomnia in the older adult population

Introduction This study aimed to explore whether the Discrepancy between the desired time in Bed and the desired total Sleep Time (DBST) index influences insomnia severity in the older adult population and examined the potential role of psychological inflexibility in this association. Methods An online survey study was conducted for older individuals aged ≥ 65 via a survey company between January and February 2023. A total of 300 responses and data without personally identifiable information were delivered to the researchers. The survey questionnaires include the DBST, Glasgow Sleep Effort Scale (GSES), Insomnia Severity Index (ISI), Dysfunctional Beliefs about Sleep-2 items (DBS-2), and Acceptance and Action Questionnaire-II (AAQ-II). Results The analysis included 295 older adult participants. The DBST index was significantly correlated with all questionnaires. Linear regression revealed the DBST index was predicted only by the ISI (β = 0.26, p = 0.003). Mediation analysis showed that the GSES (Z = 2.92, p = 0.003) and DBS-2 (Z = 2.17, p = 0.030) mediated the effect of the DBST index on the ISI, while the AAQ-II did not. Path analysis showed that the DBST could be directly predicted by the ISI (Z = 2.94, p = 0.003), GSES (Z = 2.75, p = 0.006), and DBS2 (Z = 2.71, p = 0.007) but not by the AAQ-II itself. However, the AAQ-II exerted a significant indirect effect on the ISI through the DBS-2 (Z = 2.21, p = 0.027) and GSES (z = 2.24, p = 0.025). Conclusions Our study showed that preoccupation and dysfunctional beliefs about sleep may mediate the relationship between the DBST index and insomnia severity in the older adult population. We opine that psychological inflexibility might play a significant role in insomnia severity via preoccupation with and dysfunctional beliefs about sleep.