Anxiety Disorder is a condition in which the anxiety becomes excessive and it becomes difficult for the person to control it. There are a wide variety of anxiety disorders that includes post-traumatic stress disorder, obsessive-compulsive disorder, and panic disorder. These disorders collectively are among the most common mental disorders. Unlike the relatively mild, brief anxiety caused by a stressful event, these disorders last at least 6 months and can get worse if they are not treated. Different anxiety disorder have different symptoms. All the symptoms of anxiety disorders, but, cluster around excessive, irrational fear and dread.