Linking non-suicidal self-injury to psychopathology: The utility of transdiagnostic and DSM-based models

Non-suicidal self-injury (NSSI) is a significant public health concern, and its primary formal link to the universe of psychopathology content in DSM diagnoses has been mostly through borderline personality disorder (BPD). Recent research has produced ample evidence of weaknesses of diagnoses relative to transdiagnostic psychopathology dimensions, and found that NSSI-related variables like suicidality are best predicted by transdiagnostic versus diagnosis-based variables. These findings suggest a need to characterize how NSSI may relate to different forms of psychopathology classification constructs. We examined how transdiagnostic dimensions of psychopathology relate to NSSI, focusing on how transdiagnostic (shared) variance of dimensional psychopathology spectra might differentially explained the variance in NSSI relative to traditional DSM diagnoses. In two nationally representative United States samples (Ns = 34,653 and 36,309), we modeled the common distress-fear-externalizing transdiagnostic comorbidity model and investigated questions of predictive utility of these dimensional and categorical psychopathology structures. Transdiagnostic dimensions were superior in predicting NSSI compared to common DSM-IV and DSM-5 diagnoses. These dimensions accounted for 33.6-38.7 % of NSSI variance across all analyses in both samples. DSM-IV/DSM-5 diagnoses, however, demonstrated only modest incremental prediction of NSSI over and above the transdiagnostic dimensions. These results support a transdiagnostic reconceptualization of NSSI's links with psychopathology and highlight the importance of transdiagnostic dimensions for predicting clinical outcomes relating to self-injurious behaviors. Implications for research and clinical practice are discussed.