Episodes of breathing cessation in patients with obstructive sleep apnea syndrome (OSAS) result in repetitive nocturnal oxygen desaturation, electroencephalographic arousals, and fragmentation of sleep. As a result of these changes, patients have both cardiovascular and neuropsychiatric sequelae. The most common presentations of OSAS patients are related to sleepiness and its consequences. In this review, we examine the link between OSAS and neuropsychiatric problems, and quality of life. Reports have linked OSAS to a variety of neuropsychiatric problems (psychiatric disorders, impaired cognitive function, impaired performance), poor quality of life, and an increased automobile accident rate. Treatment, usually with continuous positive airway pressure (CPAP), has been shown to improve many of the neuropsychiatric abnormalities and quality-of-life issues, however, some residual abnormalities may persist.