Nonsuicidal self‐injury in men: a serious problem that has been overlooked for too long
Authors: Nathan A. Kimbrel, Patrick S. Calhoun, Jean C. Beckham
Journal: World Psychiatry (2017)

Nonsuicidal self-injury (NSSI) refers to the act of deliberately destroying one's own body tissue without conscious intent to die and for reasons that are not socially sanctioned1-3. Common methods include cutting, scratching, and burning oneself. It is estimated that around 6% of adults in the general population have engaged in NSSI at least once during their lifetime2. While once thought to occur primarily within the context of borderline personality disorder, contemporary research demonstrates that NSSI is a transdiagnostic condition which is associated with significant functional impairment3. As a result, NSSI disorder has been included in DSM-5 as a condition for further study. By definition, the function of NSSI is different from that of suicidal behavior, where the goal is to end one's life. The most common reason that patients provide for engaging in NSSI is that they believe that it helps them to regulate their emotions. Other commonly alleged reasons include self-punishment, physiological stimulation, and communication with others1, 2. Although NSSI and suicidal behavior are clearly distinct, increasing evidence suggests that NSSI is a significant risk factor for suicidal behavior. NSSI is more strongly associated with history of suicide attempts than impulsivity, depression, anxiety, and borderline personality disorder. Actually, NSSI is a stronger prospective predictor of suicide attempts than history of suicide attempts4-6. Despite the significant implications that NSSI has for patients' health, well-being, and risk for suicide, this important clinical condition has been largely overlooked among men. This lack of attention is due in large part to the historical viewpoint that NSSI is far more common among females than males7. However, contemporary population-based studies of NSSI have consistently failed to find evidence for sex differences in rates of NSSI among adults2, 8. A recent meta-analysis including many clinical studies concluded that "women are slightly more likely than men to engage in NSSI", but the overall rate of NSSI identified among males (26.36%) was still remarkably high9. In that meta-analysis, the observed sex difference appears to have been largely driven by the inclusion of clinical samples. The discrepancy in sex differences observed between clinical and population-based studies of NSSI may be due to the fact that women are more likely to seek out psychiatric treatment than men9. Sample selection practices might also help to explain this discrepancy, as clinical settings that have a preponderance of male patients (e.g., veterans' hospitals) are likely to be under-utilized in NSSI research. In support of this view, we found that 57% of male veterans seeking treatment for post-traumatic stress disorder reported a history of NSSI10, suggesting that men who are actively seeking treatment for psychiatric issues may be just as likely as women to engage in NSSI. Sex differences in the expression of NSSI could also affect prevalence estimates. The above-mentioned meta-analysis explored sex differences in NSSI methods and found that females were more likely than males to engage in cutting, biting, scratching, and hair pulling9. Wall/object punching was not included among the twelve NSSI methods considered in the meta-analysis. However, Whitlock et al1 reported that wall/object punching is the single most common form of NSSI endorsed by college-aged men. Moreover, males who self-injure are significantly more likely to engage in wall/object punching than females who self-injure (44% vs. 19%, p<0.001). Such findings are critically important, because the vast majority of NSSI research has not examined wall/object punching as a possible NSSI method. Thus, it is entirely possible that the systematic exclusion of one of the most common NSSI methods for males to use has resulted in a significant underestimate of the true prevalence of NSSI among men. More importantly, the failure to include wall/object punching and other forms of NSSI in standard psychiatric risk assessment batteries has likely resulted in many individuals (particularly men) who engage in NSSI not being properly identified and treated, despite the fact that NSSI is one of the strongest predictors of suicide attempts identified to date. In sum, NSSI is common among men and associated with high levels of clinical distress, significant functional impairment, and increased risk for suicide attempts. It is possible that prior research has underestimated the true prevalence of NSSI in men due to biased selection and assessment methods. It is time for clinicians and researchers to recognize that NSSI is a serious problem that warrants careful investigation in both men and women. Nathan A. Kimbrel1-3, Patrick S. Calhoun1-4, Jean C. Beckham1-3 1Durham Veterans Affairs (VA) Medical Center, Durham, NC, USA; 2VA Mid-Atlantic Mental Illness Research, Education, and Clinical Center, Durham, NC, USA; 3Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC, USA; 4VA Center for Health Services Research in Primary Care, Durham, NC, USA This work was supported by the Research and Development and Mental Health Services of the Durham VA Medical Center and the VA Mid-Atlantic Mental Illness Research, Education, and Clinical Center. N.A. Kimbrel was supported by a Career Development Award (no. IK2CX000525) from the Clinical Science Research and Development (CSR&D) Service of the VA Office of Research and Development. J.C. Beckham was supported by a Research Career Scientist Award (no. 11S-RCS-009) from CSR&D. The views expressed in this letter are those of the authors and do not necessarily reflect the position or policy of the VA or the US government.