What Causes Insomnia?

Most people have experienced sleep problems at one time or another, but what causes insomnia is very individual. There are actually two different forms of insomnia—secondary (when insomnia occurs as a symptom or side effect of something else) and primary (when insomnia is a disorder in itself, not occurring as the side effect of another condition). Both are characterized by the inability to fall or stay asleep.

There are two main categories of risks that can contribute to insomnia—those that you can't change, and those that you can.

Uncontrollable Risk Factors

These variables are out of your control. Although you can't do anything to change them, it's important to know what has been associated with the development of insomnia.
  • Your age. You are more likely to experience sleeping problems as you get older. After age 40, for example, your sleep patterns change, resulting in more awakenings during the middle of the night and a harder time staying asleep.
  • Your gender. Insomnia is more common among women, but experts aren't exactly sure why. Some theories include: Women experience more extreme hormonal changes (from pregnancy to menstruation to menopause); women are more sensitive to the sounds of their own children, which causes them to wake up more often during the night; and women are at higher risk for conditions that can result in secondary insomnia, such as depression and anxiety.
  • Your health history. Several medical conditions can cause secondary insomnia. Emotional disorders (depression, anxiety, and posttraumatic stress disorder), neurological disorders (such as Alzheimer's and Parkinson's diseases), respiratory conditions (asthma), heart failure (resulting in sleep apnea and/or breathing problems), hyperthyroidism, gastrointestinal disorders (such as heartburn or GERD), and conditions that cause chronic pain (arthritis, severe headaches and fibromyalgia, for example) can all disrupt sleep quality and quantity.
  • Your socioeconomic status. Insomnia is more common in people of low socioeconomic status.
  • Your work hours. Shift workers are at a high risk for insomnia. In one survey, 65 percent of shift workers experienced symptoms of insomnia several nights each week. Shift workers over the age of 50, and those whose shift hours change on a regular basis are even more prone to sleeping problems.
While you can’t change things like health history or your work hours, you can control certain factors related to your lifestyle—the choices you make each day about what to eat and how to care for yourself. These are areas of your life where you can take proactive steps to help prevent and treat insomnia and enhance your overall health.

Controllable Risk Factors

Controllable risk factors are behaviors and factors that you can modify to lower your risk of suffering from insomnia.
  • Your diet. Eating a heavy meal too close to bedtime can interfere with sleep. To ensure you get plenty of shut-eye, try a light snack before bed, but avoid protein-rich and caffeine-containing foods and beverages. Consuming dairy products before bed can be helpful to some, since milk contains the sleep-inducing amino acid, tryptophan.
  • Your caffeine intake. Caffeine is found in beverages (coffee, tea, soda and energy drinks), foods (chocolate, for example) and even medications. As a stimulant, it can keep you awake and alert during the day, but if consumed in large quantifies or too close to bedtime, it will keep you awake when you'd rather be sleeping. Discontinue your consumption of caffeine-containing products at least 4 hours before you go to bed for optimal sleep.
  • Your exercise routine. Following a consistent exercise program can help you increase your energy levels during the day, and regulate your sleeping patterns at night. Just make sure you don't work out too close to bedtime, because it can make it harder to fall asleep. Aim for morning or afternoon workouts instead. If you must exercise at night, finish at least three or four hours before you need to go to sleep. 
  • Your stress levels. People with uncontrolled, chronic stress, including those who are overworked at the office or at home, are more prone to developing insomnia. Taking time to relax and relieve stress through exercise, meditation, yoga or other techniques can help.
  • Your outlook on life. A pessimistic outlook on life (negative thoughts, beliefs and attitudes) can significantly increase your risk of experience insomnia. People who focus on the positive tend to sleep better and experience better health in general. Changing your thoughts can change your life!
  • Your sleeping environment. It's more difficult to fall and stay asleep in a room that is too bright, noisy, or extreme in temperatures (hot or cold). Wearing a sleeping mask and closing blinds and curtains can help diminish light, while ear plugs and white noise (like a fan or CD of rain sounds) can block out disturbing sounds.
  • Your medications. Both prescription and over-the-counter medications can result in side effects such as insomnia or sleep disturbances. Common culprits include asthma, allergy and cold medicines; sedatives; and beta blockers. If you think your medication may be contributing to your symptoms, talk to your doctor about finding an alternative medication for your condition that doesn't have this negative side effect.
  • Your sleep routine. When your sleep routine is disrupted (from traveling, jetlag, staying up late, or sleeping in) you're more likely to suffer from insomnia. Keeping a consistent sleep schedule—going to bed and waking up at the same time—every day, including the weekends, will help you better regulate your sleeping patterns.
  • Your use of tobacco products. Tobacco products all contain nicotine, a powerful stimulant that can interfere with sleep. Don't smoke or use tobacco before bed, but even better—take steps to quit today. Using tobacco is a serious risk factor for many health conditions.
  • Your drinking habits. Many people think that having a drink of alcohol will help them fall asleep since it's a depressant. While this is initially true, you're more likely to wake up in the middle of the night and experience nightmares and night sweats due to withdrawal of alcohol clearing from your system. Avoid or limit your use of alcohol at least a few hours before bedtime.
Some risk factors for insomnia can’t be modified, but many can. Lifestyle changes alone may help you sleep better, but talk with your health care provider if you continue to experience problems—especially those related to factors that you can't control. Every small lifestyle change you can make, in conjunction with the treatment plan laid out by your doctor, can help you sleep soundly and improve your health and energy levels.