Excessive daytime drowsiness or difficulty staying awake may be a sign of a number of illnesses. The most prevalent is narcolepsy, a neurological condition that results in uncontrolled daytime sleep bouts. Other possible reasons include depression, which may interfere with sleep patterns, sleep apnea, where poor sleep quality promotes exhaustion, and insomnia. Excessive fatigue may also result from iron deficiency anemia and vitamin deficiencies (such as those in vitamin D or B12). To encourage wakefulness, doctors may prescribe drugs like
Modalert 200 (modafinil). A doctor's advice is necessary for an accurate diagnosis and course of therapy, however.
