Chapter 57: Anxiety Disorders

GENERAL CONSIDERATIONS

Anxiety is a diffuse, unpleasant, and often vague subjective feeling of apprehension accompanied by objective symptoms of autonomic nervous system (ANS) arousal. The experience of anxiety is associated with a sense of danger or a lack of control over events. The psychological component varies from individual to individual and is strongly influenced by personality and coping mechanisms.

Many factors contribute to the experience of anxiety by individuals in our society. We live in a rapidly changing culture characterized by continuous technologic advancements, proliferation of increasingly refined information, and a mass media and entertainment industry saturated with violence and sexuality, all of which promote feelings of insecurity. In the workplace, downsizing, restructuring, mergers, and specialization are commonplace; transient work relationships and the elimination of benefits such as health insurance and retirement provisions increase the sense of insecurity.

Anxiety is pathologic when it occurs in situations that do not call for fear or when the degree of anxiety is excessive for the situation. Anxiety may occur as a result of life events, as a symptom of a primary anxiety disorder, as a secondary response to another psychiatric disorder or medical illness, or as a side effect of a medication.

The majority of individuals with mental disorders receive psychiatric care from primary care settings, whereas <20% receive care in specialized mental health settings. Among mental disorders, anxiety disorders have the highest overall lifetime morbidity risk: specific phobia (18.4%), social phobia (13.0%), posttraumatic stress disorder (10.1%), generalized anxiety disorder (9.0%), separation anxiety (8.7%), panic disorder 6.8%), agoraphobia 3.7%), obsessive-compulsive disorder (2.7%), and any anxiety disorder (41.7%), yet only 23–59% of anxious patients receive treatment. The estimated 1-year prevalence rate is 17% with a lifetime prevalence rate at 25%. Patients with anxiety disorders are at increased risk of other medical comorbidities, longer hospital stays, more procedures, higher overall health care costs, failure in school or at work, low-paying jobs, and financial dependence in the form of welfare or other government subsidies.

PATHOGENESIS

A. Biomedical Influences

Because the symptoms of anxiety are so varied and prevalent, several etiologies exist to explain them. A recent meta-analysis revealed a significant genetic component, especially for panic disorder, generalized anxiety, and phobias. Temperament, which has genetic roots, is a broad vulnerability factor for anxiety disorders.

The inhibitory transmitter γ-aminobutyric acid (GABA) occupies ~40% of all ...