The high prevalence of obstructive sleep apnea (OSA), the resulting impaired quality of life, and the various OSA complications have contributed to continued interest in learning about the different pathophysiological aspects of this disorder.

The serotonin system regulates autonomic response and arousal during sleep apnea episodes.

Our results demonstrate improvement in sleep patterns and an increase in serum serotonin levels in OSA patients after positive airway pressure (PAP) therapy.

An increase in serum serotonin levels in OSA patients after PAP may be an effect of decreased intermittent hypoxia and may constitute criteria for the effectiveness of PAP and an improvement in sleep quality.