Prevalence of insomnia symptoms in sleep laboratory patients with and without sleep apnea.

We used the Insomnia Severity Index (ISI) to evaluate the prevalence and distribution of insomnia symptoms in 100 adult patients referred for laboratory evaluation of obstructive sleep apnea (OSA). Sixty-one percent met ISI criteria for a moderate to severe degree of insomnia symptoms. The distribution of insomnia symptoms did not differ by OSA severity.