Obstructive sleep apnea hypopnea is the most common breathing-related sleep disorder. It is marked by nocturnal breathing disturbances described as “breathing pauses” or gasping/snorting for air during the night, often resulting in daytime sleepiness.
More specifically, obstructive sleep apnea involves repeated episodes (at least 5 per hour of sleep per night) of upper airway obstruction (apneas or hypopneas) during sleep. Apnea refers to the total absence of airflow, and hypopnea refers to a reduction in airflow.
The disorder requires that the daytime sleepiness, fatigue, or unrefreshing sleep that results is not better explained by another mental disorder (including a sleep disorder, such as insomnia) and is not attributable to another medical condition.
Note: The 2013 DSM-5 indicates that this disorder is now called obstructive sleep apnea hypopnea.