The exact cause of anxiety disorders is unknown; but anxiety disorders — like other forms of mental illness — are not the result of personal weakness, a character flaw, or poor upbringing. As scientists continue their research on mental illness, it is becoming clear that many of these disorders are caused by a combination of factors, including changes in the brain and environmental stress.
Like other brain illnesses, anxiety disorders may be caused by problems in the functioning of brain circuits that regulate fear and other emotions. Studies have shown that severe or long-lasting stress can change the way nerve cells within these circuits transmit information from one region of the brain to another. Other studies have shown that people with certain anxiety disorders have changes in certain brain structures that control memories linked with strong emotions. In addition, studies have shown that anxiety disorders run in families, which means that they can at least partly be inherited from one or both parents, like the risk for heart disease or cancer. Moreover, certain environmental factors — such as a trauma or significant event — may trigger an anxiety disorder in people who have an inherited susceptibility to developing the disorder.