Effects of suppression and acceptance of sadness on the urge for non-suicidal self-injury and self-punishment.

The present study wanted to test the course of the urge for non-suicidal self-injury (UNSSI) and the urge for self-punishment (USP) when suppressing or accepting upcoming emotions in response to a sadness-inducing film clip in female participants with borderline personality disorder (BPD). Thirty-six women with BPD were allocated either to a condition in which they were asked to engage in expressive suppression or acceptance while watching a sadness-inducing film clip. Ratings of UNSSI, USP, and positive and negative emotions were assessed prior to the clip (baseline), immediately after it (t1) and after a 5min waiting period (t2), during which participants viewed landscape pictures. Additionally, physiological measures were obtained. Main results revealed a significant increase in UNSSI from baseline to t2 in the acceptance, but not in the suppression group. Furthermore, USP scores significantly increased from baseline to t2 in the acceptance, but not in the suppression condition. However, there was no differential impact on the sympathetic and parasympathetic branch depending on strategy. The results are in line with recent literature showing that expressive suppression in BPD may also have an adaptive function.