High altitudes, anxiety, and panic attacks : is there a relationship?

People exposed to high altitudes often experience somatic symptoms triggered by hypoxia, such as breathlessness, palpitations, dizziness, headache, and insomnia. Most of the symptoms are identical to those reported in panic attacks or severe anxiety. Potential causal links between adaptation to altitude and anxiety are apparent in all three leading models of panic, namely, hyperventilation (hypoxia leads to hypocapnia), suffocation false alarms (hypoxia counteracted to some extent by hypocapnia), and cognitive misinterpretations (symptoms from hypoxia and hypocapnia interpreted as dangerous). Furthermore, exposure to high altitudes produces respiratory disturbances during sleep in normals similar to those in panic disorder at low altitudes. In spite of these connections and their clinical importance, evidence for precipitation of panic attacks or more gradual increases in anxiety during altitude exposure is meager. We suggest some improvements that could be made in the design of future studies, possible tests of some of the theoretical causal links, and possible treatment applications, such as systematic exposure of panic patients to high altitude.