Positive valence systems and nonsuicidal self-injury

The present chapter focuses on reward sensitivity and positive emotionality in the development and maintenance of NSSI. The chapter discusses several theoretical models that explain specific mechanisms that may contribute to the positive reinforcement qualities of NSSI. Additionally, it considers whether the association between NSSI and other harmful emotion regulating behaviors-that is, eating disorder behaviors (EDs) and substance use behaviors (SUDs)-can be partially explained by different characteristics of the positive valence systems. The chapter concludes that NSSI, ED, and SUD have both shared and distinct correlations with measures of reward sensitivity. All three behaviors seem to be triggered by specific cues, and patients show attentional bias toward these cues. NSSI, ED, and SUD can be automatically/socially positively reinforced, which explains their continuation for some people. Furthermore, on the neurobiological level, all three behaviors seem-at the starting phase-to be related to a hyperreactivity of the reward-related systems in the brain that is driven by dopamine release. However, over time, dysregulation of the dopaminergic system leads to a hyporeactivity of the reward-related systems, which may increase susceptibility for the use of NSSI, ED, and SUD behaviors to increase positive emotional experiences. On the level of temperamental features, the findings are more mixed. It seems that NSSI and ED behaviors have more common temperamental features than SUD. Additionally, the chapter discusses transdiagnostic interventions. Finally, it provides suggestions for future research and summarizes the main findings here. To conclude, research on the reward system is challenging, and requires further research.