Stress. Concerns about work, school, health or family can keep your mind active at night, making it difficult to sleep. Stressful life events, such as the death or illness of a loved one, divorce or a job loss, may lead to insomnia.
Anxiety. Everyday anxieties as well as more-serious anxiety disorders may disrupt your asleep.
Depression. You might either sleep too much or have trouble sleeping if you're depressed. This may be due to chemical imbalances in your brain or because worries that accompany depression may keep you from relaxing enough to fall asleep. Insomnia often accompanies other mental health disorders as well.
Medications. Many prescription drugs can interfere with sleep, including some antidepressants, heart and blood pressure medications, allergy medications, stimulants (such as Ritalin) and corticosteroids. Many over-the-counter (OTC) medications, including some pain medication combinations, decongestants and weight-loss products, contain caffeine and other stimulants. Antihistamines may initially make you groggy, but they can worsen urinary problems, causing you to get up to urinate more during the night.
Caffeine, nicotine and alcohol. Coffee, tea, cola and other caffeine-containing drinks are well-known stimulants. Drinking coffee in the late afternoon and later can keep you from falling asleep at night. Nicotine in tobacco products is another stimulant that can cause insomnia. Alcohol is a sedative that may help you fall asleep, but it prevents deeper stages of sleep and often causes you to awaken in the middle of the night.
Medical conditions. If you have chronic pain, breathing difficulties or a need to urinate frequently, you might develop insomnia. Conditions linked with insomnia include arthritis, cancer, heart failure, lung disease, gastroesophageal reflux disease (GERD), overactive thyroid, stroke, Parkinson disease and Alzheimer's disease. Making sure that your medical conditions are well treated may help with your insomnia. If you have arthritis, for example, taking a pain reliever before bed may help you sleep better.
Change in your environment or work schedule. Travel or working a late or early shift can disrupt your body's circadian rhythms, making it difficult to sleep. Your circadian rhythms act as internal clocks, guiding such things as your sleep-wake cycle, metabolism and body temperature.
Poor sleep habits. Habits that help promote good sleep are called sleep hygiene. Poor sleep hygiene includes an irregular sleep schedule, stimulating activities before bed, an uncomfortable sleep environment and use of your bed for activities other than sleep or sex.
'Learned' insomnia. This may occur when you worry excessively about not being able to sleep well and try too hard to fall asleep. Most people with this condition sleep better when they're away from their usual sleep environment or when they don't try to sleep, such as when they're watching TV or reading.
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, making it difficult to get to sleep. Many people also experience heartburn, a backflow of acid and food from the stomach into the esophagus after eating. This uncomfortable feeling may keep you awake.