An experimental investigation of daytime monitoring for sleep-related threat in primary insomnia

An experimental manipulation was conducted to test the hypothesis that monitoring for sleep-related threat during the day triggers a cycle of cognitive processes that includes increased negative thinking, increased use of safety behaviours, increased perceived impairment in functioning, and increased self-reported sleepiness. Forty-seven individuals with primary insomnia were randomly assigned to a monitoring group (instructed to monitor their body sensations), a no-monitoring group (instructed to distract from their body sensations), or a no-instruction group. The manipulations to monitor or not monitor were administered immediately on waking and participants were asked to continue the manipulation throughout the experimental day. The monitoring group reported more negative thoughts, the use of more safety behaviours, and more sleepiness during the day relative to the no-instruction group. These findings offer support to a recent cognitive model, which identifies daytime monitoring for sleep-related threat as a key factor in the maintenance of the daytime distress and difficulty functioning in chronic insomnia.