Distinguishing rumination from worry in clinical insomnia.

Research has found that repetitive thought processes, such as worry and rumination, play an important role in several disorders; however, these cognitive processes have not yet been examined in insomnia. This study explores rumination and worry in insomnia by examining: 1) whether those high and low on rumination and worry differ on subjective sleep measures, and 2) whether rumination and worry are distinct processes in insomnia. Participants (N=242) were diagnosed with an insomnia disorder by sleep experts. Participants completed measures of worry and rumination and maintained a 2-week daily sleep log. Results of a multivariate analysis of variance found no main effect of worry; although high and low ruminators differed on several sleep log indices, including sleep efficiency, wakefulness after sleep onset and sleep quality. Factor analysis supported the idea that rumination and worry are separate constructs. Whereas previous research has focused on worry in insomnia, these findings suggest that rumination is important for understanding sleep disturbance. Further, although rumination and worry are both repetitive thought processes, these results indicate that they are distinct processes within insomnia and should be treated as such. The results are discussed with respect to treatment implications for Cognitive Behavioural Therapy for Insomnia.