Insomnia is a sleep disorder that hinders a person's ability to fall asleep or stay asleep at night. The disorder affects at least 35 percent of adults worldwide. Insomnia results in increased daytime sleepiness and increased risk of accidents.
Common causes of insomnia include irregular sleep schedules, stress, poor sleep habits, depression, physical pain, neurological problems, medications, and various sleep disorders.
Causes
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.
Additional common causes of insomnia include:
- Mental health disorders. Anxiety disorders, such as post-traumatic stress disorder, may disrupt your sleep. Awakening too early can be a sign of depression. Insomnia often occurs with other mental health disorders as well.
- Medications. Many prescription drugs can interfere with sleep, such as certain antidepressants and medications for asthma or blood pressure. Many over-the-counter medications — such as some pain medications, allergy and cold medications, and weight-loss products — contain caffeine and other stimulants that can disrupt sleep.
- Medical conditions. Examples of conditions linked with insomnia include chronic pain, cancer, diabetes, heart disease, asthma, gastroesophageal reflux disease (GERD), overactive thyroid, Parkinson's disease and Alzheimer's disease.
- Sleep-related disorders. Sleep apnea causes you to stop breathing periodically throughout the night, interrupting your sleep. Restless legs syndrome causes unpleasant sensations in your legs and an almost irresistible desire to move them, which may prevent you from falling asleep.
- Caffeine, nicotine and alcohol. Coffee, tea, cola and other caffeinated drinks are stimulants. Drinking them in the late afternoon or evening can keep you from falling asleep at night. Nicotine in tobacco products is another stimulant that can interfere with sleep. Alcohol may help you fall asleep, but it prevents deeper stages of sleep and often causes awakening in the middle of the night.
