The exact cause of GAD is not fully known, but a number of factors -- including genetics, brain chemistry and brain circuits, and environmental stresses -- appear to contribute to its development.
Genetics: Some research suggests that family history plays a part in increasing the likelihood that a person will develop GAD. This means that the tendency to develop GAD may be passed on in families.
Brain chemistry: GAD has been associated with abnormal functioning of certain neurotransmitters in the brain. Neurotransmitters are special chemical messengers that help move information from nerve cell to nerve cell. If the neurotransmitters are not working properly, messages cannot get through the brain properly. This can alter the way the brain reacts in certain situations, leading to anxiety.
Brain circuits: Brain areas that control mood and anxiety are thought to function abnormally in GAD -- in particular, abnormal connections between a brain region called the prefrontal cortex and another called the limbic system in GAD may interfere with someone's ability to assess and regulate risk and fear when making decisions (called "fear generalization").
Environmental factors: Trauma and stressful events, such as abuse, the death of a loved one, divorce, changing jobs or schools, may contribute to GAD. GAD also may become worse during periods of stress. The use of and withdrawal from addictive substances, including alcohol, caffeine and nicotine, can also worsen anxiety.
Nearly 4 million adult Americans suffer from GAD during the course of a year. It most often begins in childhood or adolescence, but can begin in adulthood. It is more common in women than in men.
How Is Generalized Anxiety Disorder Diagnosed?
If symptoms are present, the doctor will begin an evaluation by asking questions about your medical history and performing a physical examination. Although there are no laboratory tests to specifically diagnose anxiety disorders, the doctor may use various tests to look for physical illness as the cause of the symptoms, such as pulmonary, cardiac, thyroid or other types of endocrine problems.
The doctor bases his or her diagnosis of GAD on reports of the intensity and duration of symptoms -- including any problems with functioning caused by the symptoms. The doctor then determines if the symptoms and degree of dysfunction indicate a specific anxiety disorder. GAD is diagnosed if symptoms are present for more days than not during a period of at least six months. The symptoms also must interfere with daily living, such as causing you to miss work or school.