Vicious cycles of sleeplessness: A new scale for insomnia
Worries about sleep, negative expectations of sleep, and frustration about sleep loss are assumed to play an important role in the development of insomnia. Eight items designed to measure aspects of vicious cycles of sleeplessness (VCS), on which insomnia patients and controls were found to differ in an earlier study, were used to form a new VCS scale. A sleep questionnaire including the VCS scale