Cold Pressor Test was performed in 21 high (Highs) and 19 low hypnotizable individuals (Lows) during suggestions for analgesia (CPT+AN) and without them (CPT). Only Highs perceived lower pain intensity and exhibited higher pain threshold during CPT+AN with respect to CPT. In contrast, suggestions for analgesia (CPT+AN) increased pain tolerance in both Highs and Lows, but it was greater in the former in both conditions.

The CPT-dependent increases in heart rate and diastolic blood pressure were not modulated by hypnotizability and by suggestions for analgesia; in both groups, systolic blood pressure decreased during CPT and did not change during CPT+AN with respect to basal conditions. In contrast, during both CPT and CPT+AN, skin blood flow increased in Lows and did not change in Highs.

In conclusion, the results a) show a partial dissociation between pain experience and psychophysics; b) confirm previous findings showing a dissociation between subjective experience and autonomic correlates during pain in not hypnotized subjects; c) indirectly confirm the association of high hypnotizability with high availability of local vasodilating factors, which is independent of suggestions and is likely responsible for the lack of increase in skin blood flow in Highs.

Study supported by Fondazione ARPA, Pisa