My son was diagnosed with excessive sleepiness. What does this mean?

Sleep disorder. There are few causes of daytime sleepiness. One is obstructive sleep apnea syndrome, usually seen in obese individuals and certain other issues, the other cause is narcolepsy. Obviously we need to look into medications, etc wich can cause drowsiness and sleepiness.
How diagnosed? The answer depends on what you mean by excessive sleepiness. Depending on his age, the amount of sleep needed can vary from 7-12 hours a day. Excessive sleepiness is only a symptom. If he had a sleep study, the doctor should be able to provide some information as to what is causing his sleepiness. Causes can include narcolepsy, sleep apnea, depression, etc. Check with your doctor.
Sleep. • may occur with or without long sleep time (> or < 10 hrs). Total sleep may be over 12-14 hours. • naps generally long and unrefreshing. Sleep inertia common. Need help waking up. • mslt shows average sleep latency < 8 min and < 2 sorems. • prevalence ~1: 20, 000 • onset usually around age 10-30, develops over several weeks, then stable, resolves in 25% • CSF hypocretin normal, but histamine may b.