Nervousness and pain sensitivity: II. Changed relation in ex-addicts as a predictor for early relapse.

We recently demonstrated a coupling between nervousness and pain sensitivity in healthy volunteers, and we defined a mean ratio of nervousness/log pain threshold of 1.95 +/- 1.47 for healthy humans. Because in another study former opiate addicts were found to exhibit a persistent opioid independent analgesia, we wondered whether nervousness is also changed in these patients, or if the balance between nervousness and pain sensitivity is altered. Forty unmedicated former opiate addicts during long-term rehabilitation and 40 age-matched control subjects were included in the study. The subjects rated their nervousness prior to a cold pressor test on a Visual Analog Scale. It turned out that the average nervousness rating was higher than in the control subjects and that a distinct subgroup of pain sensitive ex-addicts exhibited a higher ratio of nervousness vs. pain threshold. In this group the risk for relapse was three to four times higher than in the other ex-addicts.