Synonyms: Sleeplessness

Medical Specialties: Family practice, Geriatrics

Clinical Definition

Insomnia, or difficulty sleeping, is a common sleep disorder. Those affected may be unable to fall sleep or to stay asleep, or may have early morning awakening, when the patient awakes several hours ahead of schedule and can't fall back asleep.

In Our Own Words

Insomnia, a common sleep disorder, affects many people, at least occasionally. Some experience chronic insomnia, having problems falling asleep, staying asleep or waking up too early and not being able to resume sleep.

A diagnosis of insomnia does not depend on the number of hours a person sleeps since the amount of sleep required varies from person to person. Instead, insomnia is an inadequate quantity or quality of sleep that makes daytime functioning difficult. Before diagnosing the problem as insomnia, other causes should be considered: medication side effects, depression or substance abuse, for starters. 

Relevant Conditions
  • Sleep disorders
  • Sleep disruption
  • Excessive daytime sleepiness
Common Types
  • Primary (not associated with other health problems)
  • Secondary (related to other health problems like diabetes)
  • Occasional
  • Chronic
Side Effects
  • Sleepiness
  • Fatigue
  • Decreased concentration
  • Irritability
  • Forgetfulness
Share this article
  • Centers for Disease Control and Prevention. "Key Sleep Disorders." May 2012. Accessed Aug. 2013.
  • Harvard Medical School. "Insomnia: Restoring restful sleep." Feb. 2009. Accessed Aug. 2013.
  • Cleveland Clinic. "What Is Insomnia?" Diseases & Conditions. Oct. 2010. Accessed Aug. 2013.
Keep Reading

Investigate your bodys signs and signals.
Try Symptom Checker