Physiological Responses to Psychological Challenge under Hypnosis in Patients Considered to Have the Hyperventilation Syndrome: Implications for Diagnosis and Therapy

Thirty patients who were considered to have the hyperventilation syndrome on clinical grounds (history and observation) were referred for testing: 29 patients completed a forced hyperventilation provocation test, and 28 underwent hypnosis during which time a psychological challenge was introduced which was meaningful to each individual patient. In 19/27 of these patients the PetCO₂ fell by an average of 18.2 mmHg and persisted spontaneously for more than three minutes. In 10 normal controls studied in a similar fashion there was an average fall of 5 mmHg. The difference in response between responders and controls/non-responders was highly significant (P< 0.001). A review of the literature is presented, for comparison. It is considered that a psychological challenge under hypnosis may have important implications for diagnosis and therapy in some patients considered to have the hyperventilation syndrome.