Cognitive behavioral treatment for insomnia is equally effective in insomnia patients with objective short and normal sleep duration.

Background: It has been suggested that insomnia patients with short sleep duration and insomnia patients with normal sleep duration may respond differently to cognitive behavioral treatment for insomnia (CBT-I). To evaluate this hypothesis, we retrospectively examined a large sample of patients with chronic insomnia regarding their outcome post-treatment and six months after participating in a two-week standardized inpatient CBT-I program.

Objectives: Seventy-two women and 20 men with chronic insomnia received standardized inpatient CBT-I and were examined with three nights of polysomnography (two baseline nights and one post-treatment night directly following the two-week treatment). Follow-up measurements of subjective insomnia symptoms were conducted after six months. The CBT-I outcome was compared between insomnia patients with polysomnographically determined short (< 6 h) and normal (≥ 6 h) sleep duration.

Results: Concerning subjective outcomes, CBT-I was equally effective in insomnia patients with objective short and normal sleep duration. Secondary analyses of polysomnographic data collected at post-treatment revealed that insomnia patients with short sleep duration showed a better treatment response in comparison to those with normal sleep duration.

Conclusions: These results suggest that the distinction in insomnia between objective short and normal sleep duration may be of limited value for treatment decisions regarding CBT-I. However, as the overall picture of the literature on this issue is not conclusive, we conclude that further prospective research is necessary to investigate the clinical validity of phenotyping insomnia patients by objective sleep data.