ИСТИНА

Introduction.– Despite extensive studies of cognitive and behavioural factors of insomnia (Perlis et al., 2011), less is known about their interactions in illness perpetuation. Objectives.– In Russia disturbances of sleep hygiene and selfrestrictive behaviour are typical for more than 70% and 40% patients respectively, making important to reveal major and interaction effects of beliefs, thoughts and behaviour in sleep in patients with primary insomnia. Methods.– 37 patients with primary chronic insomnia (12 males, 16-65 years old) were interviewed about sleep hygiene and selfrestrictive behaviour and filled Glasgow Content of Thoughts Inventory, Dysfunctional Beliefs about Sleep Scale and Insomnia Severity Index. Objective sleep was registered using polysomnography. Results.– According to moderation analysis, disturbance of sleep hygiene, dysfunctional beliefs and thoughts before sleep are all related to poorer subjective sleep (= .26-.45, P < 05, R2 = 43.9%) but the effect of beliefs is stronger in patients without disturbance of sleep hygiene (= -.30, P < 05,R2 = 7.3%). The effect of thoughts is stronger in patients with self-restrictive behaviour (= .32, P < 05, R2 = 9.1%).Morethoughts are related to longer delta-sleep latency (= .47, P < 05) especially for those with disordered sleep hygiene (= .40, P < 05) and with shorter REM-sleep latency (= -.43, P < 05). Conclusions.– In primary insomnia self-restrictive behaviour could amplify negative effect of cognitions just before sleep while an effect of beliefs increases in patients with appropriate sleep hygiene. The reported study was funded by RFBR according to the research project No. 17-29-02169 Disclosure of interest.– The authors have not supplied their declaration of competing interest.