Abstract
The aim of this study was to determine how distinctive patterns of unhelpful beliefs about sleep endorsed by insomnia patients relate to their presenting symptoms and treatment responses. A sample of 281 primary insomnia sufferers completed items comprising the Dysfunctional Beliefs About Sleep scale (DBAS-16). Their resultant scores on the four DBAS-16 subscales were then subjected to a cluster analysis, which resulted in the identification of four distinctive age-matched subgroups. Two subgroups were characterized by pathologically elevated scores on at least two of the DBAS-16 subscales, whereas the other two subgroups had subscale scores that closely resembled those of a normative sample. Subsequent comparisons showed the insomnia subgroups differed in regard to their insomnia severity, use of prescribed medication for sleep, depression and anxiety symptoms, and daytime sleepiness. Furthermore, comparisons of treatment outcomes (i.e. analysis of change scores and normative comparisons) across clusters showed that the subgroups did not benefit equally from a standardized form of Cognitive-Behavioral Therapy (CBT) for insomnia. Findings demonstrate the contribution of specific sleep-related beliefs on presenting insomnia symptoms and suggest the potential usefulness of tailoring CBT protocols to match the needs of distinctive insomnia subtypes.