Insomnia is a sleep disorder characterized by difficulties falling or staying asleep, even though people have the chance for adequate sleep.
The condition can be short term (acute), lasting days or weeks, or long term (chronic), lasting for a month or more. Acute insomnia is often caused by stressful events, such as a death in the family, said Dr. Ulysses Magalang, director of the Sleep Disorders Program at The Ohio State University Wexner Medical Center, while chronic insomnia often has a secondary cause, such as another medical or psychiatric problem.
People with insomnia can feel sleepy during the day, have difficulty concentrating and learning, and may feel irritable, anxious or depressed, according to the National Institutes of Health. Those with persistent sleep disturbances are also at increased risk for traffic accidents, have higher rates of absenteeism from work, and are less satisfied with their jobs, according to a literature review conducted by the University of Rochester in February 2010.