The condition characterized by an inability to fall asleep is insomnia. It is a sleep disorder in which a person has difficulty falling asleep, staying asleep, or waking too early and being unable to return to sleep.
Difficulty falling asleep specifically is sometimes called sleep-onset insomnia. Stress, anxiety, chronic pain, irregular schedules, medications, and conditions such as restless legs syndrome can contribute to it. Short-term insomnia may follow an upsetting event, illness, travel, or a major change in routine.
Insomnia is often confused with sleep apnea, but sleep apnea involves repeated interruptions in breathing during sleep. Narcolepsy causes sudden, uncontrollable episodes of sleepiness, while hypersomnia refers to excessive sleepiness or unusually long sleep. Insomnia can also produce daytime fatigue, irritability, and trouble concentrating, even when someone spends enough time in bed.
Persistent insomnia is commonly treated with cognitive behavioral therapy for insomnia, improved sleep habits, and, when appropriate, medication. A related fact readers often ask about is that insomnia can involve both trouble falling asleep and trouble remaining asleep; it is not limited to complete sleeplessness.