Offset Analgesia and Onset Hyperalgesia: A Comparison Between Women With Non-Suicidal Self-Injury and Healthy Women.

BACKGROUND: Individuals who engage in non-suicidal self-injury (NSSI) exhibit reduced pain sensitivity compared to the general population. It has been argued that this hypoalgesic characteristic may be attributable to hyper-effective pain modulation. However, empirical support for this theory remains inconsistent. The aim of the study was to use a combined offset analgesia (OA) and onset hyperalgesia (OH) protocol to investigate if women with NSSI have a propensity to inhibit nociceptive signals to a higher degree (stronger OA response) and facilitate nociceptive signals to a lesser degree (weaker OH response), compared to a control group. METHODS: Data was collected from 76 women, 18-35 age (37 with NSSI and 39 healthy controls). The OA and OH protocol were combined with functional magnetic resonance imaging (fMRI). RESULTS: The NSSI group displayed a weaker OH response, compared to the control group. This suggests that women with NSSI do not facilitate nociceptive signals to the same extent as healthy women. However, there were no significant differences between the groups regarding OA. Across all participants, we observed stronger activation in the primary sensory cortex during the OH condition, compared to the control condition. CONCLUSIONS: The results offer partial support for the general hypothesis that women with NSSI demonstrate enhanced pain modulation. The fMRI finding requires replication.