More than 10% of the US population have obstructive sleep apnea (OSA). Standard of care is therapy with CPAP (continuous positive airway pressure) which virtually eliminates OSA. However, most patients use CPAP only for part of the night (4-5hours) and about 50% patients discontinue CPAP long-term. Alternative therapies are limited, thus many OSA patients remain at risk of OSA sequelae (e.g. sleepiness, memory issues, high blood pressure, etc.). Importantly, different patients get OSA for different reasons, and recent data show that some of the underlying causes of OSA (endotypes) such as having a low arousal threshold (i.e. waking up easily) are associated with lower CPAP adherence. Using a randomized controlled trial design, this will be the first study using a targeted intervention to manipulate the underlying OSA causes (i.e., giving a safe hypnotic to patients with OSA to increase the arousal threshold) to test the hypothesis that endotype-targeted therapy increases CPAP-adherence in patients who have low but continued CPAP usage. Ultimately, this strategy may improve the care and outcomes of millions of undertreated OSA patients.