Anxiety disorders can fill people's lives with overwhelming worry and fear. Examples of anxiety disorders include panic disorder, obsessive-compulsive disorder, post-traumatic stress disorder, and agoraphobia. While each of these has its own distinct features, they share the common theme of excessive, irrational fear and dread. Also, the anxiety that a person feels is generally chronic, unremitting, and can grow progressively worse. People with anxiety disorders are often tormented by panic attacks, obsessive thoughts, flashbacks of traumatic events, nightmares, or countless frightening physical symptoms. In some cases, they may even become housebound. Fortunately, treatments for anxiety can be effective at any age.