Extreme REM rebound during continuous positive airway pressure titration for obstructive sleep apnea in a depressed patient

A 20% increase in REM sleep duration has been proposed as a threshold to identify REM rebound in patients with obstructive sleep apnea (OSA) who start continuous positive airway pressure (CPAP) treatment. We describe the case of one patient with OSA who showed an unexpectedly high degree of REM rebound during titration of CPAP. A 34-year-old man was diagnosed with OSA. He remained untreated for many years, during which he developed systemic hypertension, depression, and severe daytime somnolence.When he was reevaluated sixteen years later, his Epworth sleepiness score was 18, and his OSA had greatly worsened (apnea/hypopnea index: 47, lowest nocturnal saturation: 57%). He underwent a successful CPAP titration during nocturnal polysomnography. Electroencephalographic analysis of the sleep recording revealed a huge amount of REM sleep, accounting for 72% of the total sleep time. When asked, the patient referred that he had suddenly interrupted paroxetine assumption three days before the polysomnography. The very large REM rebound observed in this patient could be due to additional effects of initiation of CPAP therapy and suspension of antidepressive treatment. This case does not report any dangerous consequence, but sudden antidepressive withdrawal could be dangerous for patients with OSA who develop hypoventilation during REM sleep with CPAP application.