Insomnia may be the primary problem, or it may be associated with other conditions.

Chronic insomnia is usually a result of stress, life events or habits that disrupt sleep. Treating the underlying cause can resolve the insomnia, but sometimes it can last for years.

Common causes of chronic insomnia include:

• Stress. Concerns about work, school, health, finances or family can keep your mind active at night, making it difficult to sleep. Stressful life events or trauma — such as the death or illness of a loved one, divorce, or a job loss — also may lead to insomnia.
• Travel or work schedule. Your circadian rhythms act as an internal clock, guiding such things as your sleep-wake cycle, metabolism and body temperature. Disrupting your body’s circadian rhythms can lead to insomnia. Causes include jet lag from traveling across multiple time zones, working a late or early shift, or frequently changing shifts.
• Poor sleep habits. Poor sleep habits include an irregular bedtime schedule, naps, stimulating activities before bed, an uncomfortable sleep environment, and using your bed for work, eating or watching TV. Computers, TVs, video games, smartphones or other screens just before bed can interfere with your sleep cycle.
• Eating too much late in the evening. Having a light snack before bedtime is OK, but eating too much may cause you to feel physically uncomfortable while lying down. Many people also experience heartburn, a backflow of acid and food from the stomach into the esophagus after eating, which may keep you awake.

Chronic insomnia may also be associated with medical conditions or the use of certain drugs. Treating the medical condition may help improve sleep, but the insomnia may persist after the medical condition improves.