Mapping punishment avoidance learning deficits in non-suicidal self-injury in young adults with and without borderline personality disorder: An fMRI study

Introduction: Non-suicidal self-injury (NSSI) is a growing public health concern among young adults in both clinical and non-clinical settings. Despite evidence linking NSSI to alterations in learning from reward and punishment, this area remains understudied, especially in non-clinical populations without borderline personality disorder (BPD). Methods: We employed a modified version of the Probabilistic Stimulus Selection (PSS) task in two groups of young adults with recurrent NSSI, with (NSSI+BPD) and without BPD (NSSI), and an additional group of healthy controls (HC). While undergoing functional magnetic resonance imaging (fMRI), participants were asked to choose between pairs of stimuli with different reward probabilities. In the training phase, they received probabilistic feedback and learned to identify the most rewarding option within fixed pairs. In the test phase, these learned stimuli were recombined into novel pairs, where participants' accuracy in selecting the most rewarding and avoiding the most punishing options reflected their ability to learn from reward and punishment, respectively. Results: Compared to HC, participants in the NSSI and NSSI+BPD groups were less accurate at avoiding the most punishing options than at choosing the most rewarding options, and showed reduced activity in the nucleus accumbens (NAcc) during punishment avoidance relative to reward selection. Limitations: The modest sample size, descriptive rather than modeling approach, and absence of ecological momentary assessments may limit the results. Conclusion: Findings suggest that reduced activation of the NAcc when avoiding loss may underlie difficulties in learning to avoid punishment in young adults with NSSI, regardless of the presence of BPD.