LEP and obstructive sleep apnea syndrome: Studies in normal volunteers showed that selective serotonin reuptake inhibitors (SSRIs) increase genioglossus electromyogram (EMG).88 More recent animal studies questioned the magnitude of the effect and relevance of serotonergic pathways,89 while clinical trials were disappointing.90 However, our study suggests that leptin-mediated serotonergic pathways may be significant in the settings of obesity hypoventilation combined with upper airway obstruction (90% of patients with OHS and 10%–40% of obese OSA patients).