I sleep with my Mind's eye open: Cognitive arousal and overgeneralization underpin the misperception of sleep.

Background and Objectives: Misperception of sleep (e.g., underestimation of sleep time relative to objective measures) is a common feature of insomnia and other psychopathologies. To elucidate the mechanisms underlying this tendency, we examined the role of pre-sleep cognitive arousal and overgeneralization.
Methods: We monitored the sleep of 54 community dwellers (the majority being university students), using actigraphy and a sleep diary for 7 days. Immediately after this period, the participants provided an additional global evaluation of their sleep for the past week. In this global evaluation, participants were asked to estimate their average number of hours of sleep and the duration of time taken to fall asleep (sleep onset latency) across the past seven nights.
Results: Single-night misperceptions (difference between actigraphy and sleep diary estimations) of sleep time and sleep onset latency were significantly associated with pre-sleep cognitive arousal, but not with overgeneralization. In contrast, global misperception of sleep (difference between sleep diary and global estimations) were associated with overgeneralization, but not with cognitive arousal.
Limitations: Our sample mainly consisted of female university students, which limits the generalizability of the results.
Conclusions: Misperception of sleep occurs in two cases: (1) in the case of a single night due to excessive arousal, and (2) in the case of multiple nights due to overgeneralization.
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