Insomnia is difficulty getting to sleep or staying asleep, or having nonrefreshing sleep for at least 1 month.

Psychophysiological insomnia; Learned insomnia; Chronic insomnia; Primary insomnia

Primary insomnia refers to insomnia that is not caused by any known physical or mental condition.

Insomnia is caused by many different things. The most common causes of insomnia are:

• Alcohol
• Anxiety
• Coffee
• Stress

Secondary insomnia is caused by a medical condition. Depression is a very common cause of secondary insomnia. Often, insomnia is the symptom that causes people with depression to seek medical help.

Review Date: 08/17/2009
Reviewed By: Andrew Schriber, MD, FCCP, Specialist in Pulmonary, Critical Care, and Sleep Medicine, Virtua Memorial Hospital, Mount Holly, New Jersey. Review provided by VeriMed Healthcare Network. 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)