Insomnia is complex problem caused by many factors that may act individually or in combination with others.
Psychological or emotional issues can cause insomnia. Stress, anxiety, depression and other behavior or mood-related problems are among the psychological causes of sleepless nights for many people. Stress hormones can make the mind active at night and keep someone awake for hours. Studies show that insomnia commonly accompanies anxiety disorders.
Depression and insomnia can be linked in more ways than one. The chemical imbalance thought to be involved in depression can cause symptoms of insomnia. In addition, the worries that normally accompany depression could make it difficult for you to sleep at night.
Psychoactive drugs or stimulants
Any psychoactive drug or stimulant (including caffeine) cause chemical reactions in the brain that affect the release of certain hormones causing some people to suffer from insomnia.
Insomnia may be a side effect of some antidepressants, blood pressure medications, anti-allergy drugs and stimulants.
Caffeine: Drinks that contain caffeine increase your alertness. Having coffee, tea, cola and energy drinks in the late afternoon or evening will likely keep you awake at night.
Smoking: Smokers are at risk for insomnia because the nicotine in tobacco products is a stimulant. Those who drink alcohol are not spared from sleep problems either. Alcohol may quickly induce sleep, but it prevents deeper stages of sleep and may awaken you in the middle of the night. As consequence, your body fails to rejuvenate.
Insomnia may develop in patients suffering from diseases that cause pain and other discomfort. Restless leg syndrome, cancer, congestive heart failure, diabetes, lung disease, hyperthyroidism, stroke, Parkinson's disease and Alzheimer's disease are among the conditions linked to insomnia. Additionally, insomnia can also be present in sleep disorders such as sleep apnea and narcolepsy.
Certain circumstances or conditions can increase your risk for insomnia.
More on Risk Factors for Insomnia
Szuba, M. et al. Insomnia Principles and Management
National Heart Lung and Blood Instutute. What causes insomnia?
http://www.nhlbi.nih.gov/health/dci/Diseases/inso/inso_causes.html accessed 10.22.09
Schneck, C., Sleep: The Mysteries, the Problems and the Solutions. Penguin Group. 2007
Mayo Clinic. Insomnia: Causes.1.8.2009