What Causes Coma-Like Deep Sleep?

Updated June 15, 2018
Teenage boy in a deep sleep

Some people sleep so deeply that they are quite difficult to awaken and appear to be in a coma-like sleep. This can present problems in people who need to wake up to get to school or work at a specific time yet persistently sleep through alarms.

The Deepest Sleepers

Coma-like sleep is characterized by a deep sleep devoid of movement. Sleeping so deeply it appears coma-like is only an issue if it affects your daily functioning. For example, if you consistently sleep through alarms or can't wake up to care for young children, this merits a visit to a doctor for a referral to a sleep specialist for further evaluation. This may involve a physical examination and a sleep study to rule out any medical cause.


Medication can have a huge impact on how a person sleeps; some medications make people sleep much more deeply. Harvard Health warns that some antihistamines (those with diphenhydramine) and motion sickness medication can make users sleep more deeply than usual, as can some anti-depressants or anti-anxiety medications.

People react differently to medications, however, so a medication that lulls one person into a deep, coma-like sleep may have no impact on another user's sleep. Additional medications that can make people sleep more deeply than usual include:

  • Blood pressure medications
  • Some cancer medications
  • Muscle relaxants
  • Pain medications
  • Seizure medication
  • Recreational drugs and alcohol

Medical Conditions

The American Sleep Association classifies recurring coma-like sleep as Long Sleeping Disorder, characterized by individuals needing 10 to 12 hours of sleep nightly in order to function. People with this sleep disorder are usually difficult to awaken and should strive to get the sleep their body needs. Otherwise, they may find it difficult to function during the day.

Patients recovering from surgery or major medical events may sleep more deeply than usual as their body or brain works to repair damage. Heart disease and thyroid disorders can cause increased and deeper sleep too.

Depression and Deep Sleep

While some people with depression experience sleep disturbances to where they can't have a restful night's sleep, others experience deeper sleep while depressed. Depression - regardless of its effect on sleep - should be evaluated and treated.

Hypersomnia and Narcolepsy

These two sleep disorders aren't typically associated with deep nighttime sleep, but instead can be the cause of deep, coma-like sleep during the day. Hypersomnia causes an irresistible urge to sleep during the day and extended sleeping at night, while narcolepsy is characterized by sudden sleep accompanied with paralysis any time of day. Neither condition is considered curable, but is instead helped with maximized nighttime sleep and, in some cases, medication.

Teenagers and Deep Sleep

Teenagers experience a shift in their circadian rhythm that can prompt incredibly deep sleep, making it difficult to wake them up. This can frustrate or alarm parents.

As their brains work to rapidly develop and their bodies work to produce growth hormone, sleep becomes even more vital to a teenager's health and well-being. The deep, coma-like sleep that teenagers often experience is simply their brains and bodies working hard to transition from adolescence into adulthood.

Gender Differences

Women tend to have more lifetime events with the potential to affect their sleep, including menstruation, menopause, and pregnancy. Women also tend to spend more time during sleeping hours in deep sleep than men do, researchers report, and they are more likely to experience sleep disorders.

A Deeper Sleeper

Sleeping so deeply to where it appears to be coma-like is not generally classified alone as a sleeping disorder and isn't necessarily a concern unless it causes problems. It's important to understand that this is simply how some people sleep and is not a sign of laziness. If deep sleep is causing issues, visit a medical professional to ensure an underlying medical condition isn't causing the issues with sleep.

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What Causes Coma-Like Deep Sleep?