Insomnia that lasts more than a few days but less than 1 month is called short-term insomnia. This is usually due to a bigger stressor, such as a short-term illness. Chronic insomnia can last months or years. Chronic insomnia is usually due to chronic medical or psychiatric illness or the use of medications. Some studies suggest that one in three Americans suffers from chronic insomnia.
Most emotional disorders can cause sleep disturbance.
Chronic insomnia can be a symptom of depression, anxiety, dementia, or panic disorder. A number of medical problems can also cause insomnia. Cardiovascular disease, heartburn, asthma, and thyroid disease are among the most common. Drugs are also common causes of insomnia. Stimulants like caffeine can disturb sleep.