The clinical population targeted will be newly diagnosed patients with polysomnographically diagnosed OSA who are not currently taking hypnotics for concomitantly diagnosed insomnia. Outpatients who are also judged to be capable to follow the study procedures (consent, timelines, visits, questionnaires) and who do not have any concurrent disease that in the view of the investigator will interfere with participation in the trial to completion will be included. Approximately 160 subjects were recruited (80 per treatment arm) in the recent trial of eszopiclone. This size is expected to be able to discern an important difference of 80 minutes per night. In the current clinical population newly prescribed CPAP at Mount Sinai Hospital, the average compliance after 4 weeks of initiation of nCPAP was 4:01 (SD 2:59) hours per night. To be able to discern a difference of at least 1 hour (60 minutes) in usage per night, including entirely non-adherent patients who do not use treatment at all as 'zero hour' users, would require randomization of 264 patients (132 per group).

Our hypothesis for this study is that initial titration of CPAP treatment of OSA may be improved by initial prescription of a common hypnotic, zopiclone. To answer this question we intend to recruit 264 consecutive consenting subjects with OSA confirmed by a physician (ABSM or by a respirologist with extensive sleep medicine experience) with supportive polysomnography results who are willing to initiate long-term CPAP treatment.

Background: Obstructive sleep apnea (OSA) is a common sleep breathing disorder that is associated with serious complications. Continuous positive airway pressure (CPAP) is the treatment of choice for most patients but its use in the real world is limited by low patient adherence which may result in sub-optimal outcomes for some patients. A single hypnotic with low risk of adverse effects is a cost-effective intervention to augment the currently low adherence to CPAP, especially if only prescribed for a limited time. The hypnotic is generic zopiclone 3.75-7.5 mg at bedtime for up to 14 doses.

The clinical population targeted will be newly expert physician-diagnosed patients polysomnographically supported OSA who are not currently taking hypnotics for concomitantly diagnosed insomnia. Outpatients who are also judged to be capable to follow the study procedures (consent, timelines, visits, questionnaires) and who do not have any concurrent disease that in the view of the investigator will interfere with participation in the trial to completion will be included.

Inclusion Criteria:

• MD diagnosis of obstructive sleep apnea
• No previous use of CPAP
• No concurrent use of hypnotic medication

Exclusion Criteria:

• Fatal comorbidities (i.e., life expectancy less than 6 months)
• Contraindications for CPAP use
• Pregnancy
• Liver Failure