Nearly one in five Americans suffers from sleep disorders that result in excessive daytime sleepiness. Excessive daytime sleepiness can be a symptom of several sleeping disorders such as:
An overnight stay at a sleep center is required to diagnose most sleep disorders.
Excessive daytime sleepiness can also be a symptom of various other neurological disorders, a side effect of certain medications, a result of head injury or a tumor, or a number of other medical conditions. If no other underlying disorder is found in someone with excessive daytime sleepiness, the condition is referred to as idiopathic hypersomnia (or primary hypersomnia).