AimsSelf-Harm (SH) is defined as “any act of self-injury or poisoning carried out by a person irrespective of their motivation”. SH increases the risk of adverse outcomes including suicide attempts, necessitating early intervention. The most widely reported reason for SH is to relieve negative affect (NA), with NA precipitating SH engagement. SH participants show altered reward processing, particularly reward hypersensitivity. NA could trigger reward hypersensitivity and therefore SH engagement. However, the interaction between NA and reward processing in SH remains unclear.Aim: To investigate whether those who SH show differences in processing SH stimuli compared to healthy controls (HCs) following NA induction.Hypothesis: NA induction will result in SH participants having significantly shorter reaction latency (RL) and significantly greater reaction accuracy (RA) in the SH condition of the Incentive Delay task (IDT) than HCs.Methods16–25-year-old SH (n = 35) and HC (n = 20) participants were recruited on social media. Participants completed the Trier Social Stress Test, to induce NA, followed by the IDT. In the latter, participants were cued to respond to a target as quickly as possible, and on responding were shown images of either a SH act (SH condition), people socializing (social condition) or money (monetary condition), where each condition had control trials where a neutral image was shown, which participants also had to respond to (SH neutral, social neutral and monetary neutral conditions respectively). RA was the percentage of IDT trials in which participants responded within the target's presentation time. RL in the IDT was the time (seconds) between the target appearance and the participant's response.ResultsA linear mixed effects model showed no significant main effect of group on RL (SH vs HC), condition (Social, SH or Monetary) or group x condition interaction (p > 0.05). There was a significant main effect of condition on RA (p < 0.05) but not group or group x condition interaction (p > 0.05). Past-week SH frequency and RA were significantly and positively correlated in social, social neutral and monetary conditions (p < 0.05).ConclusionOverall, there was a non-significant effect of NA on reward processing. However, as greater past-week SH frequency was significantly associated with greater RA, understanding how reward processing and NA interact in SH can provide greater insight into its triggers. Given this study's limited sample size and cross-sectional nature, future studies should investigate how NA and reward processing interact longitudinally and in larger samples to understand how SH can be reduced.

Introduction Self-Harm (SH) is any act of self-injury carried out by somebody irrespective of motivation. SH most commonly functions to relieve negative affect (NA). Tentative evidence suggests reward processing is altered in SH. NA may trigger reward hypersensitivity and therefore SH. Whether NA influences reward processing in SH remains unclear. Objectives To investigate whether self-harmers differ in motivation to obtain SH stimuli than healthy controls (HCs) following NA induction. Hypothesis After NA induction, SH participants will have a significantly shorter reaction latency (RL) and greater reaction accuracy (RA) than HCs in the SH condition of the Incentive Delay (ID) task. Methods 16-25-year-old SH (n=35) and HC (n=20) participants were recruited online and underwent the Trier Social Stress Test, to induce NA, followed by the ID task, where participants were cued to respond to a target as quickly as possible. On responding, an image of either a SH act (SH Condition), people socializing (Social Condition) or money (Monetary Condition) appeared. Each condition included control trials showing a neutral image. RA was the percentage of trials responded to within the target’s presentation time. RL was the time (seconds) between target appearance and participants’ response. Results There was no significant main effect of group, condition or group x condition interaction for RL. There was a significant main effect of condition (p < 0.05) but not of group nor a group x condition interaction for RA. Conclusions Reward processing did not differ in the SH group compared to HCs post-NA induction. Future studies could investigate reward processing in longitudinal and larger SH samples. Disclosure No significant relationships.