The test-retest reliability of the hyperventilation provocation test

The hyperventilation provocation test (HPT) has been widely used for reproducing symptoms of panics. It is assumed that subjects experience similar symptoms on consecutive occasions of hyperventilation. Fourteen subjects with a history of panics and fourteen without such a history underwent the HPT on two occasions one week apart. In the group of 28 subjects as a whole, there were moderate similarities between the HPTs in both the choice and severity of symptoms reported, even when pre-existing symptoms were controlled statistically. Nevertheless, in the subject-by-subject analysis, many subjects showed no resemblance between the two HPTs in the choice of symptoms. This suggests that many subjects would not show any resemblance between the symptoms experienced in an HPT and those of their latest panic even if hyperventilation occurred in that panic.