Subjective sleep characteristics in primary insomnia versus insomnia with comorbid anxiety or mood disorder

Abstract

We assessed subjective sleep measures in a cohort of 146 patients with chronic insomnia and hypothesized that these measures may differ depending on the presence as well as the type of comorbid psychiatric disorders. All patients were consecutively referred to a third line sleep medi-cine center and underwent an extensive clinical intake by both a sleep physician and a psychologist. Psychodiagnostics were performed according to the DSM-IV criteria. Subjective sleep was assessed by sleep diaries and the insomnia severity index. Insomniacs with anxiety disorders showed a relatively higher total sleep time and higher sleep efficiency than the two other groups. Furthermore, the number of awakenings was higher and time in bed after the final awakening was lower in patients with comorbid anxiety disorders when compared to the two other groups. Although subjective total bedtimes where comparable, patients with comorbid anxiety disorders on average reported a striking 2 h more sleep per night and around a 20% higher sleep efficiency than patients with comorbid mood disorders. Patients with comorbid mood disorders showed a trend towards a higher Insomnia Severity Index-score when compared to primary insomniacs. Insomniacs with comorbid anxiety disorders present with a markedly higher sleep efficiency and total sleep time. On the other hand, these patients describe more fragmented sleep. Our findings may have practical implications for more tailored cognitive behavioral treatment in insomniacs with and without different types of psychiatric comorbidity.