Acrophobia is an extreme or irrational fear of heights, especially when one is not particularly high up. It is a type of specific phobia that causes people to feel extremely fearful and anxious when they think of tall heights or are positioned at a significant height. The fear is excessive to the situation, persistent, and can cause a person to avoid situations where they may be high up. People with acrophobia can experience a panic attack in high places and become too agitated to get themselves down safely. The main symptom of acrophobia is feeling intense anxiety and fear of heights. Some people with acrophobia fear significant heights such as a tall bridge while others also fear shorter heights such as being on a ladder. The causes of acrophobia are not fully understood, but researchers believe that it may be evolutionary or learned, or that a person may develop it following a traumatic experience. Acrophobia is treatable with psychological therapy called exposure therapy.