If you have an anxiety disorder, you're not alone. Anxiety disorders, such as panic disorder, obsessive-compulsive disorder, and PTSD, are the most common mental illnesses reported in the United States. Approximately 40 million people—roughly 18 percent of the population—have an anxiety disorder. While there are treatments available for anxiety disorders, they usually do not get rid of the symptoms completely. Most people with anxiety have to learn to live with their disorder, which can plague them for years or even for their whole life.