Table 3.

Zero-order correlations between placebo-condition CPM and placebo-controlled morphine responses.

Morphine Effect Measure	Correlation (r)
Ischemic MPQ-S	0.09
Ischemic MPQ-A	−0.03
Ischemic MPQ-PPI	0.25***
Ischemic VAS Intensity	0.18*
Ischemic VAS Unpleasantness	0.17*
Thermal MPQ-S	0.18*
Thermal MPQ-A	−0.09
Thermal MPQ-PPI	0.31***
Thermal VAS Intensity	0.22**
Thermal VAS Unpleasantness	0.07
Unpleasantness Factor	−0.24***
Sedation Factor	0.08
Euphoria Factor	0.06

^*p<.05

^**p<.01

^***p<.001

Note: MPQ-S, MPQ-A, and MPQ-PPI = McGill Pain Questionnaire-Short Form Sensory, Affective, and Present Pain Intensity subscales respectively. The CPM variable was derived so that greater negative values indicate greater descending inhibition. Morphine analgesic effects were derived so that more negative values indicate greater morphine analgesia. Factor scores indexing morphine subjective effects were derived such that greater positive scores indicated greater subjective effects with morphine.