Results from Two Countries on How Thwarted Interpersonal Needs Contribute to Understanding Self-Harm.

Abstract Self-harming behavior (SHB) represents an important public health issue and is one of the most critical predictors of completed death by suicide. The current study evaluated the incremental contribution of the Interpersonal Theory of Suicide constructs of thwarted belongingness and perceived burdensomeness for the prediction of SHB beyond that associated with having a psychiatric diagnosis. Community adults from two different countries included a Portuguese sample of 414 adults, aged between 18 and 65 years (M  = 45.09, SD = 13.11), and predominantly female (79%), and an American sample of 290 adults (198 men, 91 women, 1 unreported) with a mean age of 37.76 years (SD  = 10.84) ranging from 20 to 71, who participated online. Results demonstrated mediation effects for perceived burdensomeness in the association of thwarted belongingness with SHB, partial mediation in the Portuguese sample and full mediation in the American sample. Findings also indicated that the interaction between thwarted belongingness and perceived burdensomeness failed to make a statistically significant contribution to the prediction of SHB. The results are discussed within the Interpersonal Theory of Suicide and its relevance for clinical practice.