Inclusion Criteria:  Age 18+ Chronic pain Chronic opioid use (daily use for >3 months duration) Apnea-hypopnea index >/= 5 events/hr (screening sleep study will be performed)  Exclusion Criteria:  Already using CPAP or non-invasive ventilation on a daily basis Use of opioids outside medical supervision (i.e. recreational use) Pain due to active cancer Prisoners Pregnancy Psychiatric illness other than treated mood disorders Life expectancy <12 months Anticipated inability to sleep in the laboratory setting or to use CPAP Unable or unwilling to provide informed consent or comply with research procedures