Anxiety disorder is characterized by excessive, exaggerated feeling of nervousness, apprehension, fear, or worry about everyday life events with no obvious reasons for worry. People with symptoms of generalized anxiety disorder tend to always expect disaster and can't stop worrying about health, money, family, work, or school. In people with GAD, the worry often is unrealistic or out of proportion for the situation. Daily life becomes a constant state of worry, fear, and dread.

Anxiety may occur without a cause, or it may occur based on a real situation but may be out of proportion to what would normally be expected. Severe anxiety can have a serious impact on daily life. Eventually, the anxiety so dominates the person's thinking that it interferes with daily functioning, including work, school, social activities, and relationships.

Psychologist David H. Barlow of Boston University conducted a study that showed three common characteristics of people suffering from chronic anxiety, which he characterized as "a generalized biological vulnerability," "a generalized psychological vulnerability," and "a specific psychological vulnerability A number of factors -- including genetics, brain chemistry 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 levels 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 out of balance, messages cannot get through the brain properly. This can alter the way the brain reacts in certain situations, leading to anxiety.
• Environmental factors: Trauma and stressful events, such as abuse, the death of a loved one, divorce, changing jobs or schools, may lead 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.

There are over 100 symptoms of anxiety.
Because each person has a unique chemical make up, the type, number, intensity, and frequency of anxiety symptoms will vary from person to person. Anxiety affects the way a person thinks, but the anxiety can lead to physical symptoms, as well. Symptoms of anxiety can include:

• Excessive, ongoing worry and tension
• An unrealistic view of problems
• Restlessness or a feeling of being "edgy"
• Irritability
• Muscle tension
• Headaches
• Sweating
• Difficulty concentrating
• Nausea
• The need to go to the bathroom frequently
• Tiredness
• Trouble falling or staying asleep
• Trembling
• Being easily startled

In addition, people with Anxiety often have other anxiety disorders (such as panic disorder,obsessive-compulsive disorder, and phobias), suffer from depression, and/or abuse drugs or alcohol.