The goal of this prospective cohort study is to study patients referred for sleep study by in-lab polysomnography in the Jordan University Hospital and the Jordan Hospital or with an at-home sleep study kit. The main aims are: * To prospectively obtain demographic and clinical information of patients referred for a sleep study. * To determine the diagnostic value of facial discoloration as potential marker for obstructive sleep apnea to increase detection rate for the condition. * To establish a correlation between obstructive sleep apnea and vasovagal symptoms with resulting increased smoking tendency and study the effect of treatment on the disorders. * To determine the association between timing of appearance of obstructive sleep apnea symptoms and initiation of smoking.