Study objectives: To examine polysomnographic parameters and sleep diary data, as well as the prevalence of sleep apnea and periodic limb movement disorder (PLMD) in older chronic users of zopiclone compared with aged-matched drug-free patients with insomnia and good sleepers.
Methods: Polysomnographic data were collected at a university-based outpatient clinic for adults and elderly. Seventeen patients using zopiclone on a daily basis for at least 1 year were compared with 64 drug-free patients with insomnia and 26 good sleepers. Mean (SD) age was 63.8 (7.0) years. Outcome measures were polysomnographic sleep parameters, sleep diary data, and psychological symptoms, as well as prevalence estimates of sleep apnea and PLMD.
Results: The zopiclone users spent more time awake, had longer sleep latencies, and reduced sleep efficiency compared with the good sleepers. The amount of slow-wave sleep was also significantly lower in the zopiclone group compared with the good sleepers. There were no differences between the zopiclone and insomnia group on any of the polysomnography parameters. A similar pattern was found for data based on sleep diaries. The frequency of sleep apnea (apnea-hypopnea index > 10) were 41% to 42% in both the zopiclone and insomnia groups, compared with 12% in the good sleepers group, whereas there were no significant group differences in the frequency of PLMD. The zopiclone group reported higher levels of anxiety and depression compared with the other groups.
Conclusions: This study suggests that the sleep of chronic users of zopiclone is no better than that of drug-free patients with insomnia. It is disturbing that 41% of the patients treated pharmacologically for insomnia also had sleep apnea. We suggest careful sleep assessment as a prerequisite for long-term prescription of sleep medications.