Anxiety disorders involve a state of distressing chronic but fluctuating nervousness that is inappropriately severe for the person's circumstances.

Anxiety is a normal response to a threat or to psychologic stress and is experienced occasionally by everyone. Normal anxiety has its root in fear and serves an important survival function. When someone is faced with a dangerous situation, anxiety induces the fight-or-flight response. With this response, a variety of physical changes, such as increased blood flow to the heart and muscles, provide the body with the necessary energy and strength to deal with life-threatening situations, such as running from an aggressive animal or fighting off an attacker. However, when anxiety occurs at inappropriate times, occurs frequently, or is so intense and long-lasting that it interferes with a person's normal activities, it is considered a disorder.

Anxiety disorders are more common than any other category of mental health disorder and are believed to affect about 15% of adults in the United States. However, anxiety disorders often are not recognized by people who have them or by health care practitioners and consequently are seldom treated.

How Anxiety Affects Performance The effects of anxiety on performance can be shown on a curve. As the level of anxiety increases, performance efficiency increases proportionately, but only up to a point. As anxiety increases further, performance efficiency decreases. Before the peak of the curve, anxiety is considered adaptive, because it helps people prepare for a crisis and improve their functioning. Beyond the peak of the curve, anxiety is considered maladaptive, because it produces distress and impairs functioning.

Causes

The causes of anxiety disorders are not fully known, but both physical and psychologic factors are involved. Because anxiety disorders are prevalent in some families, heredity probably plays a role. Anxiety is viewed at a psychologic level as a response to environmental stresses, such as the breakup of a significant relationship or exposure to a life-threatening disaster. When a person's response to stresses is inappropriate or a person is overwhelmed by events, an anxiety disorder can arise. For example, some people find speaking before a group exhilarating. But others dread it, becoming anxious with symptoms such as sweating, fear, rapid heart rate, and tremor. Such people may avoid speaking even in a small group.

Anxiety disorders may also be caused by a physical disorder or the use of a drug. For example, an overactive thyroid or adrenal gland can cause anxiety, as can a tumor called a pheochromocytoma. Drugs that can cause anxiety include corticosteroids, cocaine, amphetamines, ephedrine, and sometimes caffeine if too much is consumed. Withdrawal from alcohol or certain sedatives can also cause symptoms of an anxiety disorder. In older people, dementia may be the most common cause of anxiety.

Did You Know... Anxiety disorders are the most common type of mental health disorder. People with an anxiety disorder are more likely than other people to have depression.

Symptoms

Anxiety can arise suddenly, as in panic, or gradually over minutes, hours, or days. Anxiety can last for any length of time, from a few seconds to years. It ranges in intensity from barely noticeable qualms to a full-blown panic attack (see Anxiety Disorders: Panic Attacks and Panic Disorder), which may cause shortness of breath, dizziness, an increased heart rate, and trembling (tremor).

Anxiety disorders can be so distressing and interfere so much with a person's life that they can lead to depression (see Depression and Mania: Depression). People who have an anxiety disorder (except for certain very specific phobias, such as fear of spiders) are at least twice as likely to have depression as those without an anxiety disorder. Sometimes depression develops first and an anxiety disorder develops later.

Diagnosis

The diagnosis of an anxiety disorder is based largely on symptoms. The ability to tolerate anxiety varies, and determining what constitutes abnormal anxiety can be difficult. Doctors usually use specific established criteria, based mainly on symptoms and exclusion of other causes of symptoms.

Doctors ask whether family members have had similar symptoms. A family history of an anxiety disorder (except posttraumatic stress disorder, which results from a specific event) may help doctors make the diagnosis. Doctors also do a physical examination. Blood and other tests may be done to check for disorders that can cause anxiety.

Treatment

Accurate diagnosis is important because treatment varies from one anxiety disorder to another. Additionally, anxiety disorders must be distinguished from anxiety that occurs in many other mental health disorders, which involve different treatment approaches. Depending on the anxiety disorder, drug therapy or psychotherapy (such as behavior therapy), alone or in combination, can significantly relieve the distress and dysfunction for most people.

Antianxiety Drugs Drug Uses Some Side Effects Comments Benzodiazepines Alprazolam Chlordiazepoxide Clonazepam Clorazepate Diazepam Lorazepam Oxazepam Generalized anxiety disorder Panic disorder Phobic disorders Sleepiness, impaired coordination, and slowed reaction time May lead to drug dependence Most commonly used type of antianxiety drug Promote mental and physical relaxation by reducing nerve activity in the brain Begin to work quickly, sometimes within an hour Should not be used by people who are dependent on alcohol Buspirone   Generalized anxiety disorder Dizziness and headache Does not cause drowsiness or interact with alcohol Does not lead to drug dependence May take several weeks to start working Antidepressants* Selective serotonin reuptake inhibitors (such as paroxetine) Norepinephrine/serotonin reuptake inhibitors (such as duloxetine and venlafaxine) Monoamine oxidase inhibitors Tricyclic antidepressants (such as clomipramine) Generalized anxiety disorder Panic disorder Phobic disorders Obsessive-compulsive disorder Posttraumatic stress disorder See Depression and Mania: Drugs Used to Treat Depression See Depression and Mania: Drugs Used to Treat Depression *Not all of the antidepressants listed work for all of the uses that are listed.

Last full review/revision August 2007 by John H. Greist, MD; James W. Jefferson, MD