Hypersomnolence is marked by excessive and chronic daytime sleepiness. People who suffer this disorder do not enjoy restorative nighttime sleep, though some individuals sleep up to seven hours a night.
These sufferers nap throughout the day—at work, sitting down at dinner, and even at social events. The sleepiness is gradual and not normally experienced as an onslaught. The napping does not give the sufferer relief.
This disorder is common in both males and females, and onset age is 17 to 24. About 1 percent of the population experiences symptoms of hypersomnolence, particularly the prolonged impairment of alertness upon waking (sleep drunkenness).