CONTEXT: Intermittent use (i.e., a few nights per week) of hypnotic medication is often recommended for the treatment of chronic insomnia despite an absence of efficacy and safety data using this regimen.STUDY OBJECTIVES: To evaluate the clinical efficacy and safety of intermittent pharmacotherapy for chronic insomnia.DESIGN AND SETTING: Randomized, double-blind, placebo-controlled, parallel groups, clinical trial at six sleep research sites.PATIENTS: One hundred-sixty-three (115 women, 48 men; mean age 44.1+ SE. 0.9 years), DSM-IV-defined primary insomnia patients were randomized, 134 patients completed the study.INTERVENTIONS: Eight weeks of treatment with either zolpidem 10 mg or placebo. Patients were instructed to take medication when they felt they needed it, but at least three and no more than five times per week.MAIN OUTCOME MEASURES: Investigator and Patient Global Ratings were the primary outcome variables. Secondary measures from daily questionnaires to assess efficacy, rebound insomnia and drug taking behavior.RESULTS: The Investigator's Global Rating indicated that intermittent use of zolpidem produced a significantly better therapeutic effect and significantly reduced insomnia severity throughout the 8-week study relative to placebo. Zolpidem was found to be effective in initiating and maintaining sleep on nights taken, as compared to placebo, based upon the Patient's Global Ratings and all subjective sleep variables. No evidence of rebound insomnia was found on nights that zolpidem was not taken. The number of nights a pill was taken did not differ between groups, nor did frequency of pill taking change in either group across the duration of the study. There were no significant effects of treatment upon quality of life or neurocognitive measures.CONCLUSIONS: Zolpidem 10 mg is effective in treating insomnia when used intermittently, without evidence of discontinuation effects or increased frequency of pill taking.
Analysis of Variance Double-Blind Method