Anxiety is an unpleasant emotional experience of apprehension about something that has not yet happened. Pathological anxiety usually has no clear anxiogenic factor and the person is overreacting and persisting for too long. Anxiety disorders include obsessive-compulsive disorder, generalized anxiety disorder, post-traumatic stress disorder (PTSD), social anxiety disorder, and panic disorder. OCD is a neurological disorder characterized by obsessive-compulsive symptoms and the coexistence of self-compulsions and counter-compulsions in the consciousness. The strong conflict between the two causes anxiety and distress, and social functioning is severely impaired. OCD is difficult to treat, and surveys show that only 19% of patients have satisfactory outcomes; about 70% of patients require long-term or even lifelong medication maintenance; 10% of patients have poor outcomes. Panic disorder is a sudden and intense experience of fear, often accompanied by palpitations, shortness of breath, dizziness, tremor and sweating and other physical symptoms, sometimes accompanied by a sense of near death, often occurring suddenly and remitting on its own, and can recur several times in a short period of time. Social anxiety disorder, formerly known as social phobia, is a condition in which patients experience excessive anxiety, fear, a feeling of incompetence, confusion, embarrassment and humiliation, and even avoidance behavior in social situations and social operations. The core symptoms are fear of being scrutinized, fear that others will see that they are nervous and unnatural; and fear of operating or performing in public. Generalized anxiety disorder is a type of anxiety disorder that lacks a clear object and specific content of worry and nervousness. PTSD is a sudden, threatening, or catastrophic life event that results in the delayed onset and long-term persistence of a psychiatric disorder in individuals, characterized by re-experiencing trauma and accompanied by emotional irritability and avoidance behaviors.