This document discusses anxiety and anxiety disorders. It defines anxiety and fear, and notes that both involve physiological arousal through the sympathetic nervous system. Anxiety can be adaptive in moderation by increasing preparedness, while fear triggers the fight or flight response. Anxiety disorders are associated with neurotransmitter imbalances. The document reviews the DSM-5 criteria and common symptoms of several specific anxiety disorders, including generalized anxiety disorder, social anxiety disorder, panic disorder, agoraphobia, and specific phobias. It discusses common risk factors and treatments, which include psychological therapies focusing on exposure.