Why Do People Hurt Themselves? A New Conceptual Model of Nonsuicidal Self-Injury

Researchers have wondered how the brain creates emotions since the early days of psychological science. With a surge of studies in affective neuroscience in recent decades, scientists are poised to answer this question. In this target article, we present a meta-analytic summary of the neuroimaging literature on human emotion. We compare the locationist approach (i.e., the hypothesis that discrete emotion categories consistently and specifically correspond to distinct brain regions) with the psychological constructionist approach (i.e., the hypothesis that discrete emotion categories are constructed of more general brain networks not specific to those categories) to better understand the brain basis of emotion. We review both locationist and psychological constructionist hypotheses of brain-emotion correspondence and report meta-analytic findings bearing on these hypotheses. Overall, we found little evidence that discrete emotion categories can be consistently and specifically localized to distinct brain regions. Instead, we found evidence that is consistent with a psychological constructionist approach to the mind: A set of interacting brain regions commonly involved in basic psychological operations of both an emotional and non-emotional nature are active during emotion experience and perception across a range of discrete emotion categories.

Published prevalence estimates of nonsuicidal self-injury (NSSI) among nonclinical samples are highly heterogeneous, raising concerns about their reliability and hindering attempts to explore the alleged increase in NSSI over time. Accordingly, the objectives of this study were to investigate the influence of methodological factors on heterogeneity in NSSI prevalence estimates, explore changes over time, and estimate overall international NSSI prevalence. Results showed that methodological factors contributed over half (51.6%) of the heterogeneity in prevalence estimates, and, after adjusting for these factors, NSSI prevalence did not increase over time. Overall, pooled NSSI prevalence was 17.2% among adolescents, 13.4% among young adults, and 5.5% among adults. Clearly, development of standardized methodology in NSSI research is crucial if accurate estimates are desired. © 2014 The American Association of Suicidology.

People have engaged in self-injury-defined as direct and deliberate bodily harm in the absence of suicidal intent-for thousands of years; however, systematic research on this behavior has been lacking. Recent theoretical and empirical work on self-injury has significantly advanced the understanding of this perplexing behavior. Self-injury is most prevalent among adolescents and young adults, typically involves cutting or carving the skin, and has a consistent presentation cross-nationally. Behavioral, physiological, and self-report data suggest that the behavior serves both an intrapersonal function (i.e., decreases aversive affective/cognitive states or increases desired states) and an interpersonal function (i.e., increases social support or removes undesired social demands). There currently are no evidence-based psychological or pharmacological treatments for self-injury. This review presents an integrated theoretical model of the development and maintenance of self-injury that synthesizes prior empirical findings and proposes several testable hypotheses for future research.