Anxiety disorders are a category of mental disorders characterized by feelings of anxiety and fear, where anxiety is a worry about future events and fear is a reaction to current events. These feelings may cause physical symptoms, such as a racing heart and shakiness. There are a number of anxiety disorders: including generalized anxiety disorder, a specific phobia, social anxiety disorder, separation anxiety disorder, agoraphobia, and panic disorder among others. While each has its own characteristics and symptoms, they all include symptoms of anxiety.