Table of Contents
Introduction
Insomnia comes from the Latin words for “no sleep.” Insomnia is characterized by:
- Difficulty falling asleep
- Difficulty staying asleep
- Waking up too early
- Poor quality ("non-restorative") sleep
Insomnia may be primary or secondary:
- Primary insomnia means that the inability to sleep is not caused by other health problems.
- Secondary insomnia is due to other health conditions that interfere with sleep. It is also called “comorbid insomnia.”
Duration of Insomnia
Insomnia is often categorized by how long it lasts:
- Transient insomnia lasts for a few days.
- Short-term insomnia lasts for no more than 3 weeks.
- Chronic insomnia occurs at least 3 nights per week for 1 month or longer.
Related Disorders
Review Date: 06/11/2010
Reviewed By: Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine,
Harvard Medical School; Physician, Massachusetts General Hospital.
Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M.,
Inc.
A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org)

