Introduction: The purpose was to explore the development and remission of insomnia in the general population. Models of chronic insomnia suggest that cognitive and behavioural factors may maintain and worsen sleep problems. This had not been investigated prospectively before.
Method: A survey with sleep related questionnaires was sent out to 5000 in the general public three times over 1, 5 years. Respondents were classified as normal sleepers, poor sleepers, and insomniacs.
Results: Statistical software EXACON was used to examine expected and unexpected movement between sleep classifications over time. It was typical to remain in the same sleep category (p<.0001), and typical to move from insomnia to poor sleep (p<.0001). It was atypical to move from normal sleep to poor sleep or insomnia (p<.0001), and atypical to move from poor sleep or insomnia to normal sleep (p<.0001). Poor sleepers showed most classification movements. A multinomial logistic regression explored if worry (APSQ), somatic arousal (PSAS), monitoring (SAMI), dysfunctional beliefs (DBAS) and safety behaviours (SRBQ) could predict development to insomnia and normal sleep respectively for people with poor sleep at baseline. The model was significant (p<.01) with increased safety behaviours as a unique predictor of movement to insomnia (p<.01) Decreased safety behaviours showed a tendency towards significance for development to normal sleep (p>.01).
Conclusion: Complete remission was unusual once sleep problems had developed, although the severity varied over time. Safety behaviours seem to influence the development of insomnia for people with poor sleep. The role of psychological processes for insomnia needs to be explored further.