To Örebro University

Psychological factors and their association with persistent insomnia

Objectives: Models of chronic insomnia suggest that cognitive and behavioural factors may maintain sleep problems. This study focused on five psychological factors outlined by Harvey (2002): unhelpful beliefs about sleep, monitoring for sleep-related threats, sleep-related safety behaviours, pre-sleep somatic arousal, and sleep-related worry. The aim was to investigate if the degree of psychological factors at baseline would differ between three groups of stable sleep classifications over 18 months, defined as having either “insomnia disorder”, or “poor sleep” or “normal sleep” at both times. Another aim was to investigate if people with persistent insomnia would differ from those with improved sleep (e.g. insomnia to normal sleep) regarding the same psychological factors.

Methods: A longitudinal design with two measurement points, 18 months apart, was used. Participants (n=1561) from a randomly selected sample of the general population completed a survey that included the five factors outlined by Harvey (2002).

Results: The persistent insomnia group had higher scores on all factors, compared with the persistent poor sleep group (worry: d = .92; beliefs: d = .85; somatic arousal: d = .58; monitoring: d = .88; safety behaviours: d = .91) who in turn had higher scores than the persistent normal sleep group (worry: d = .72; beliefs: d = .46; somatic arousal: d = .79; monitoring: d = .67; safety behaviours: d = .84). Investigating insomniacs only, the persistent insomnia group displayed more worry (d=.47), safety behaviours (d=.45), and more monitoring (d=.40) at baseline, compared with the group of people whose insomnia remitted fully over time. Those with remitted insomnia had a larger change (lowering) of worry (d=.43), dysfunctional beliefs (d=.52), monitoring (d=.52) and safety behaviours (d=.67) between the two measure points compared with the persistent insomnia group.

Conclusion: Persistent insomnia was linked to a higher degree of psychological factors compared with those with persistent poor sleep or persistent normal sleep. Worry, dysfunctional beliefs, monitoring and safety behaviours may have maintaining effects, as lower scores at baseline and/or a lowering of them over time were associated with remittance from insomnia.