Excessive Daytime Sleepiness (EDS) is the main symptom of narcolepsy. Excessive daytime sleepiness causes the patient to tend to fall asleep easily. This can happen in relaxed situations and also at inappropriate times and places.
Patients may fall asleep while watching TV, reading a book, driving, attending a meeting, or engaging in a conversation. The daytime sleepiness is present even after normal nighttime sleep. Patients may describe this symptom as being tired, fatigued, sleepy, feeling lazy, or having low energy. Excessive daytime sleepiness is present throughout the day but the patient, with extreme effort, may be able to resist the sleepiness for some time.
Finally, it becomes overwhelming and results in a sleep episode of varied duration (seconds to minutes). In addition to daytime sleepiness, repetitive, irresistible, and unintentional sleep attacks may occur throughout the day. Excessive daytime sleepiness usually impairs a patient's functioning because it reduces motivation and vigilance, interferes with concentration and memory, and increases irritability.
Pathologic daytime sleepiness is the most frequent first sign in narcolepsy.
Other Definition:
Excessive daytime sleepiness (EDS) refers to the symptom of being overly sleepy