On the flip side, there are people who chronically fall asleep too much, often at unusual times. Like Mr. Benedict from the Mysterious Benedict Society book series, narcoleptics are susceptible to sudden, uncontrollable sleep attacks. Sufferers of this disorder may stop talking midsentence and fall asleep or become extremely drowsy after being triggered by a stressor.
Obviously, randomly sleeping can be inconvenient for sufferers, like in driving, eating, or their daily careers. Narcolepsy is linked to a lack of the neurotransmitter hypocretin, which keeps humans alert and awake.