If you find yourself nodding off several times during the day, despite your best efforts to stay awake, you may have hypersomnia. If you are not spending enough time in bed at night, then you are not considered hypersomnic; instead you are just sleep deprived and you need to get more sleep. If you are spending enough time in bed at night but you find that you can’t sleep or you wake repeatedly throughout the night, this is called insomnia and the treatments for this condition are different than those for excessive sleepiness.

In order to diagnose you with excessive sleepiness, the doctor will ask you questions about your personal and medical history. Especially important is information about your sleep habits and your level of sleepiness during the day. The doctor will likely try to determine a cause such as those mentioned above and so may ask you about your drug and alcohol use, medications and supplements you take, your cancer history or history of recent head trauma, or about any of your relatives who may have excessive sleepiness or any of its possible causes.

You may be asked to undergo some tests to help pinpoint a cause for your excessive sleepiness. Common tests include blood tests, brain scans such as computed tomography (CT) or magnetic resonance imaging (MRI), an electroencephalogram (EEG) to measure brain waves, and a sleep test called a polysomnogram.