What does it mean that it doesn't hurt? Understanding the role of pain in nonsuicidal self-injury.

Comments on an article by J. Fales et al. (see record  2021-79063-001 ). Fales and colleagues resent a meta-analysis indicating that people with borderline personality disorder (BPD) report reduced physical pain during laboratory pain induction tasks. This adds to existing evidence that people with a history of non-suicidal self-injury (NSSI) similarly report reduced laboratory pain. As Fales and colleagues discuss, this is an intriguing phenomenon with potentially significant clinical implications: a diminished, if not wholly absent, acute pain response could explain why people with BPD engage in NSSI, a behavior that should ordinarily cause significant pain and, thus, be highly aversive. Despite the considerable data regarding the pain experience of people with BPD in the laboratory, the same is not true regarding pain during real-life NSSI events. This distinction is meaningful because, in the laboratory, participants respond to painful stimuli chosen and administered by experimenters. In contrast, during NSSI events in their daily lives, individuals themselves both determine the nature of the stimulus, deciding what method to use, how severely to injure, as well as a range of other potentially significant factors, and self-administer it. As a result, while people with BPD, relative to someone without BPD, may experience less pain following an experimentally controlled stimulus, this does not mean that they do not experience pain during NSSI.