How is persistent insomnia maintained? A prospective study on 50-60 years old adults in the general population.

OBJECTIVES

The purpose of this study was to examine whether arousal, distress and sleep-related beliefs are related to the maintenance of insomnia in old adults.

DESIGN

From a randomly selected sample from the general population (N=3,600; 50-60 years old), 2,239 participants filled out a baseline and 1-year follow-up survey.

METHODS

Logistic regressions were used to investigate whether psychological mechanisms were related to sleep status (insomnia: N=230; poor sleep: N=210; normal sleep: N=658; good sleep: N=253) over one year. Cluster analysis was employed to assess whether it was possible to classify the participants based on their profiles of psychological functioning.

RESULTS

The results showed that arousal, sleep-related beliefs about future consequences and anxiety were significantly related to the maintenance of insomnia (14-66% of the variance). Out of the individuals with persistent insomnia, 67% belonged to a cluster characterized by high scores on arousal, sleep-related beliefs and anxiety, 24% to a cluster defined by medium scores on the three mechanisms and 9% to a cluster characterized by low scores on the three mechanisms.

CONCLUSIONS

This investigation shows not only that arousal, sleep-related beliefs and anxiety are associated with the maintenance of persistent insomnia, but also that these mechanisms often co-occur in individuals with persistent insomnia.