title: Benzodiazepines and zolpidem for chronic insomnia: a meta-analysis of treatment efficacy.
abstract: OBJECTIVE
  To evaluate the efficacy of benzodiazepines and zolpidem tartrate in chronic insomnia based on a quantitative review of literature.
  
  
  METHODS
  Articles from 1966 to 1996 were identified using MEDLINE, by a manual review of relevant journals, and from bibliographies of identified articles.
  
  
  METHODS
  Studies using randomized, double-blind, placebo-controlled, parallel or crossover designs with benzodiazepines or zolpidem in adults younger than 65 years with chronic insomnia (modified Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria for primary insomnia) were selected for review. Self-report and polysomnographic measures of sleep-onset latency, total sleep time, number of awakenings, and sleep quality were selected as outcomes.
  
  
  METHODS
  Twenty-two studies met the selection criteria. A combined test of Pvalues was performed, pooling broadly from the 22 studies to determine whether medication was superior to placebo. A combined test of effect sizes was performed on the subset of studies that reported effect size information to determine the magnitude of medication effect.
  
  
  RESULTS
  A homogeneous sample of studies summarized 1894 patients treated for a median duration of 7 days. The combined test of P values demonstrated that medication was superior to placebo in all 4 outcome measures. Treatment response was moderate in magnitude by the combined test of effect sizes.
  
  
  CONCLUSIONS
  Benzodiazepines and zolpidem produced reliable improvements in commonly measured parameters of sleep in patients with chronic insomnia. Relative to the chronic and recurring course of insomnia, both the limited duration of treatments studied and the lack of follow-up data from controlled trials represent challenges for developing evidence-based guidelines for the use of hypnotics in the management of chronic insomnia.
authors.affiliation: Department of Psychiatry, School of Medicine, University of Pittsburgh, Pa, USA.
authors.forename: P D
authors.initials: PD
authors.lastname: Nowell
authors.forename: S
authors.initials: S
authors.lastname: Mazumdar
authors.forename: D J
authors.initials: DJ
authors.lastname: Buysse
authors.forename: M A
authors.initials: MA
authors.lastname: Dew
authors.forename: C F
authors.initials: CF
authors.lastname: Reynolds
authors.forename: D J
authors.initials: DJ
authors.lastname: Kupfer
mesh_terms: D000328:Adult; D014151:Anti-Anxiety Agents / Q000627:therapeutic use*; D001569:Benzodiazepines / Q000627:therapeutic use*; D002908:Chronic Disease; D006801:Humans; D006993:Hypnotics and Sedatives / Q000627:therapeutic use*; D008875:Middle Aged; D011725:Pyridines / Q000627:therapeutic use*; D016032:Randomized Controlled Trials as Topic; D012890:Sleep; D007319:Sleep Initiation and Maintenance Disorders / Q000188:drug therapy*; D013223:Statistics as Topic; D016896:Treatment Outcome; D000077334:Zolpidem
chemical_list: D014151:Anti-Anxiety Agents; D006993:Hypnotics and Sedatives; D011725:Pyridines; D001569:Benzodiazepines; D000077334:Zolpidem