Table 1 Participant selection criteria

Inclusion criteria

 • Adults ≥ 21 years of age

 • Diagnosis of OSA with an AHI ≥ 5 on a diagnostic polysomnogram

 • Accept PAP as primary/sole OSA therapy, been given a prescription for PAP, and have had an opportunity to use PAP for ≥ 1 month

 • Meets the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5), Insomnia Research Diagnostic Criteria

 • A sleep onset latency or wake time after sleep onset > 30 min for 3 or more nights per week during 2 weeks of sleep diary monitoring [1]

 • An Insomnia Severity Index (ISI) score ≥ 10, indicating at least “mild” insomnia

Exclusion criteria

 • Current, untreated, psychiatric disorder (i.e., major depression)

 • A lifetime diagnosis of any psychotic or bipolar disorder

 • Imminent suicide risk

 • Alcohol or drug abuse within the past year

 • Terminal illness (i.e., cancer) or neurological degenerative disease (i.e., dementia)

 • Current use of medications known to cause insomnia (e.g., stimulants)

 • Comorbid narcolepsy, idiopathic hypersomnia, restless legs syndrome, periodic limb movement during sleep (PLMS with arousal > 15 per hour), or severe circadian rhythm sleep disorder (with severity defined by bedtimes later than 3:00am or rise times later than 11:00 am)

 • Consumption of more than 2 alcoholic beverages per day on a regular basis (defined as 5 or more times per week)

Additional considerations

 • Varying levels of PAP adherence are being included, with the candidates’ most recent diagnostic PSG to determine if they meet the AHI inclusion and PLM exclusion criteria

 • Individuals using sleep aids (prescribed or over-the-counter) are not excluded as long as they still meet criteria for insomnia disorder

 • Participants who report consuming alcohol regularly after 7:00 pm at the screening visit are asked to discontinue this practice at least 2 weeks prior to baseline assessment

 • Individuals using psychotropic medications (SSRI or SNRI) are eligible for the study, as long as medication doses are stable for at least 3 months with at least partial remission (via structured interview) of related mood or anxiety disorder

 • All participants are asked to not initiate other treatment for their insomnia during the trial, but are not excluded if they choose to do so (they are asked to report other treatments if they choose to obtain such treatment)