Intrusive thoughts and their relationship to actigraphic measurement of sleep: towards a cognitive model of insomnia

Although cognitive over-arousal has been hypothesised as a causal factor in sleep-onset insomnia, relatively little is known about the specific pre-sl eep intrusions which delay sleep. To investigate this relationship adequate ly 'live', verifiable, unobtrusive and independent monitoring of thought pr ocess and sleep pattern is essential. This study was designed with these re quirements in mind. Voice-activated audiotape recordings of spontaneous tho ughts, and actigraphic data from which to estimate sleep parameters, were o btained over three consecutive nights from 21 participants (63 subject nigh ts). Content analysis of transcribed audiotapes yielded eight categories of pre-sleep intrusion. Results from correlational and regression analyses in dicate that thinking about sleep and the anticipated consequences of poor s leep, along with general problem-solving are the strongest predictors of ob jective sleep latency. Principal Components Analysis suggests that intrusio ns can be subsumed under one of three factors: 'active problem-solving', 'p resent state monitoring' and 'environmental reactivity'. Implications for c ognitive models and treatments of insomnia are discussed. (C) 2000 Elsevier Science Ltd. All rights reserved.