CARDIOVASCULAR CONDITIONING AND ANTICIPATORY NAUSEA AND VOMITING IN CANCER-PATIENTS

Explanations of individual differences in susceptibility to learning o f anticipatory nausea and/or vomiting (AN/V) in cancer patients have f ocused mainly on the patients who develop AN/V. On the basis of condit ioning theory, however, one would expect that all patients who experie nce post-treatment nausea and/or vomiting (PN/V) should develop AN/V. Consistent with findings demonstrating that conditioned responses are more easily established in autonomic-reactive individuals, we have pre viously reported that patients who do not develop AN/V (noAN/V) are le ss autonomic reactive than the AN/V patients. Thus, we hypothesized th at the noAN/V patients might not show classical conditioning to the sa me degree and extent as the AN/V patients and that conditioning may be the mediating mechanism in AN/V. This study presents data from 36 pat ients. Among the 28 patients who experienced PN/V, 16 developed AN/V. We found no systematic group differences in severity of PN/V or antiem etic treatment. Before chemotherapy, all patients were tested in a sig naled reaction-time paradigm. We used two different tones (CSs), one o f which was always followed by a noise (UCS) as a button-press signal. The patients who later developed AN/V demonstrated significantly shor ter reaction times, and also showed enhanced cardiovascular reactivity to the tone followed by the UCS (CS+) in comparison with the nonsigna l tone (CS-). The noAN/V patients did not show differential cardiovasc ular responses to the CS+ and CS-.