Aim: Twenty patients (14 of them women) suffering from psychophysiological insomnia (PPI) were enrolled for cognitive behavior therapy (CBT). The mean age of the patients was 56.9 years, and the mean duration of insomnia morbidity was 8.9 years. Each received individual combined CBT treatments consisting of stimulus control, sleep reduction, cognitive therapy and sleep hygiene education over a period of 1 month.
Methods: Just before the CBT and after its completion, sleep measurements were conducted that involved (i) sleep logs, Dysfunctional Beliefs and Attitudes about Sleep Scale (DBAS), and the Pittsburgh Sleep Quality Index (PSQI); (ii) actigraphy measurement; (iii) dissociation between subjective and objective evaluation of sleep calculated from sleep logs and actigraphy results; and (iv) correlation between DBAS and the aforementioned sleep parameters. Because the intention was to focus on patients' incorrect cognition about sleep, the definition 'changes in dissociation between the sleep log and actigraphically measured sleep' was used as the primary outcome and 'changes in DBAS score' as the secondary outcome.
Results: After the CBT the following was found: (i) underestimation by PPI patients of the objective evaluation of sleep; (ii) a decrease in the dissociation between the subjective and objective evaluation of sleep; (iii) improvement of the DBAS; and (iv) improvement of sleep logs and actigraphy measurements. Moreover, there was a correlation between the improvement of PSQI, sleep logs and DBAS.
Conclusion: CBT for insomnia is able to redress incorrect cognition about sleep, leading to improvement of the disorder.