Insomnia is a sleep disorder characterized by persistent problems falling asleep or staying asleep. People with insomnia typically complain that their sleep is unrefreshing and that they often suffer from drowsiness, lack of focus and energy, fatigue, impaired mental function, and moodiness during waking hours.

Anyone can suffer from insomnia at any age: 33% of adults experience insomnia at least intermittently as well as 20% to 40% of children and teenagers. Approximately 10% of the general population is affected by chronic insomnia, defined as symptoms occurring at least three times per week for at least three months. Insomnia can reduce life expectancy and increase the risk of cardiovascular events, compromised immunity, obesity, diabetes, seizures, asthma, memory problems, depression, irritability and motor vehicle accidents.

Common causes of insomnia are stress, pain, anxiety, depression, and age-related changes such as menopause. Other contributing factors include excess alcohol or caffeine consumption, excessive napping in the day, noise, jet lag, and certain medications.

The diagnosis and treatment of insomnia are complex because of its potential association with other health issues. Treatment of insomnia includes alleviating any physical and emotional problems that may be contributing to the condition as well as lifestyle changes, behavioral therapy and drug therapy.