Acrophobia is an extreme or irrational fear or phobia of heights, especially when one is not particularly high up. It belongs to a category of specific phobias, called space and motion discomfort, that share both similar causes and options for treatment. People with acrophobia can experience a panic attack in high places and become too agitated to get themselves down safely. Approximately 2–5% of the general population has acrophobia, with twice as many women affected as men. The term is from the Greek: ἄκρον, ákron, meaning "peak, summit, edge" and φόβος, phóbos, "fear".