Test Your Knowledge

There are many causes of insomnia. Lifestyle factors that can cause insomnia include:

• Foods. Foods that contain caffeine, such as chocolate, may cause insomnia. Salty foods may disrupt sleep by causing thirst. Eating too much or too soon before bedtime may also interrupt sleep.
  
  
• Drinks. Drinks that contain caffeine, such as coffee and soft drinks, may result in insomnia. Alcohol may initially induce sleep, but can result in waking up too early.
  
  
• Stress. Life circumstances, such as a new baby, job loss or death of a loved one, are common causes of transient insomnia.
  
  
• Changes in environment or work schedules. Travel between time zones or working the night shift can disrupt the body's circadian rhythm (internal clock that guides the wake-sleep cycle, metabolism, body temperature and other bodily functions). A bed partner's snoring can also cause insomnia.
  
  
• Poor sleep habits. Excessive daytime napping and using the bed for activities other than sleeping and sex can sometimes cause insomnia.

Many medications may also cause insomnia in some people. These may include some medications that are prescribed to treat the condition, especially if they are used for lengthy periods of time.

Numerous medical and mental health conditions may also cause insomnia. Chronic pain diseases such as osteoarthritis and inflammatory conditions such as allergic rhinitis (hay fever) may make it difficult to sleep. People suffering from peptic ulcers often experience insomnia. Hormonal changes in the body also can affect a person’s sleep pattern. Pregnant women require more sleep, especially early in pregnancy, but may also have insomnia as a result of the hormonal changes experienced during pregnancy. After puberty, some teenage girls may experience insomnia as a result of the hormonal changes associated with the onset of menstruation. After menopause, women are at higher risk of chronic insomnia, especially those who experience severe hot flashes. People with mental illnesses such as depression or anxiety disorders are also affected with insomnia.

In addition, other sleep disorders may produce changes in sleep and cause insomnia. These include:

• Sleep apnea. A disorder in which a person's breathing stops and starts many times during sleep.
  
  
• Restless legs syndrome. Sleep disorder characterized by unpleasant sensations in the legs that are described as creeping, crawling, tingling, pulling or painful.
  
  
• Periodic limb movement disorder (nocturnal myoclonus). Characterized by periodic episodes of repetitive jerking and kicking during sleep.
  
  
• Circadian rhythm sleep disorder. Involves disruption of the sleep cycle. Common examples are jet lag and sleep problems associated with shift work.

For many people, a combination of these factors causes insomnia. For example, a person experiencing stress at work may eat or drink later in the evening, resulting in insomnia.

In some cases, the cause of insomnia cannot be determined. This is called idiopathic insomnia. People with idiopathic insomnia often have trouble falling or staying asleep their entire lives. Physicians believe it may be caused by imbalances of certain chemicals in the brain. Patients with idiopathic insomnia often have family members with the condition.