Anxiety refers to an unpleasant emotional state, a response to anticipated threat or to specific psychiatric disorders. In anxiety, the anticipated threat is often imagined. Anxiety consists of physiological and psychological features. The physiological symptoms can include breathing dif-ficulties (hyperventilation, shortness of breath), palpitations, sweating, light-headedness, diarrhea, trembling, frequent urination, and numbness and tingling sensations. The anxious person is usually hypervigilant and startles easily. The subjective psychological experience of anxiety is characterized by feelings of apprehension or fear of losing control, depersonalization and derealization, and difficulties in concentration. Strains around the performance of social roles (e.g., spouse, parent, wage earner) and certain life situations (e.g., separating from parents when starting school or leaving home, illness) can generate anxiety symptoms. Other factors can contribute to the etiology of anxiety, such as use of alcohol, caffeine and otherstimulant drugs (e.g., amphetamine), a family history of anxiety symptoms...