Till Örebro universitet

Introduction: Models of chronic insomnia suggest that cognitive and behavioural processes may maintain and worsen sleep problems. Our aim was to investigate if the degree of psychological processes at baseline would differ between three groups of stable sleep categories over 1.5 years, defined as having “insomnia disorder”, “poor sleep” or “normal sleep” at both times. Another aim was to investigate if groups with trajectories to worsened sleep (e.g. poor sleep to insomnia) would differ from groups with stable or improved sleep regarding the psychological processes.

Method: A survey with sleep-related questionnaires was sent to the general population. A multivariate analysis of variance was performed to investigate differences in psychological processes between sleep category groups. The dependent variables were safety behaviours, sleep related worry, selective attention, somatic arousal, and dysfunctional beliefs about sleep. The independent variable (1-9) consisted of nine possible combinations of development between the categories insomnia disorder, poor sleep, and normal sleep from time one until time two, 1.5 years later.

Results: There was a difference between the groups on the combined psychological processes F (5, 1238) = 19.36, p = .0001, with the groups explaining between 16-38 % of the variance of the five processes. Further analyses revealed that there were significant differences between the stable sleep groups on all psychological processes, where “stable insomnia” reported higher scores than “stable poor sleep” which in turn reported higher scores than “stable normal sleep” (p = .0001). “Poor sleep to insomnia” had significantly higher means on safety behaviours and worry compared with “stable poor sleep” and “poor sleep to normal sleep” (p = .0001).

Conclusion: The results suggest that the psychological processes are associated with different sleep trajectories over time, with worry and safety behaviours as possible risk factors for insomnia for people with poor sleep.