This isn't a "light" topic to discuss in my opinion, however I find it relevant and important. The question I've always wondered is: is pain tolerance something physiological or psychological in the case of self-injury?
Wikipedia informed me that there is a difference between "pain tolerance" and "pain thresholds." Pain tolerance is the maximum level of pain that a person is able to tolerate. pain threshold is the point along a curve of increasing perception of a stimulus at which pain begins to be felt.
From the article, I learned pain perception can be altered, so the question I asked, in my opinion and what I gathered from the article, is seen more through a psychological approach then a physiological approach.
In this laboratory investigation, a sample from a community, and they examined differences between pain threshold and pain endurance. One group of participants self-injured and the control group was exposed to pressure pain applied to the finger. The participants who self-injured had higher pain thresholds (time to report pain) and endured pain for a longer time than the controlled participants. Higher pain thresholds were found in those who self-injured the longest. Although, this was not the case for pain endurance. Greater pain endurance was linked to neuroticism and negative beliefs about self worth. Some people who self-injure think they deserve pain and suffering.