DECREASED NOCICEPTIVE SENSITIVITY - A BIOLOGICAL RISK MARKER FOR OPIATE DEPENDENCE

In recent studies using a cold presser test we could show that former opiate addicts are persistently less pain-sensitive than healthy contr ols, indicating a neurophysiologic dysfunction in these patients. In t he present study we addressed the issue of whether this dysfunction wa s caused by the drug abuse or already existed prior to the heroin addi ction, and whether it is restricted to pain sensitivity or affects som atosensory or nociceptive sensitivity in general. After validating the method we obtained retrospective ratings for the pain, cold and warmt h sensitivity for the time before addiction, during addiction and duri ng detoxification. Ex-addicts perceive themselves less pain- and cold- sensitive than healthy controls, and no difference was detectable betw een the pre-addiction and the rehabilitation ratings, although nocicep tive sensitivity is highly increased during detoxification. Warmth sen sitivity was not different to healthy controls and was not affected by drug withdrawal. Our findings suggest that a decreased nociceptive se nsitivity may already precede opiate addiction pointing to physiologic al dysfunctions in heroin pre-addicts.