Specific phobias are marked by fears and avoidance of specific objects or situations, as well as recognition that the fears are unreasonable. Social phobias involve fears of performing certain behaviors in front of other people, such as public speaking. Biological factors, such as having sympathetic nervous systems that are overly reactive and slow to become accustomed to false signals of fear, can also increase people's likelihood of developing an anxiety disorder. Researchers believe these biological tendencies are inherited. Once people have developed a phobia, their fear is maintained by a number of factors, including the relief they feel when avoiding the feared object or situation, and the cognitive biases that cause them to focus on threats and to interpret situations in the most threatening way.
Panic disorder is less common, but usually more serious, than phobias.
People with panic disorder experience recurrent panic attacks. These individuals may also develop agoraphobia, an avoidance of any situation that might trigger a panic attack. Panic attacks are often triggered by stress. They turn into full-blown panic disorder when people focus their attention on the physical symptoms. Ironically, fear of these symptoms actually increases their severity, making panic more likely.