Delineating the unique contributions of mindfulness skills in predicting engagement in suicide attempts and non-suicidal self-injury among individuals with borderline personality disorder

The current research tested whether four dimensions of mindfulness – acceptance without judgment, observing, describing and acting with awareness – taught during 20 weeks of dialectical behavior therapy skills training (DBT-ST) predicted frequency of two forms of self-inflicted injury (SII), i.e. suicide attempts (SAs) and non-suicidal self-injury (NSSI), at baseline and mediated the relationship between pre-post treatment change in frequency of SAs/NSSI and DBT-ST. Eighty-four suicidal individuals with borderline personality disorder were enrolled in a single-blinded randomized trial comparing DBT-ST treatment to a waitlist control group. A series of regressions revealed no relationship between dimensions of mindfulness and self-inflicted injury at baseline. Although no significant effect of DBT-ST on SAs was found, a causal mediation analysis revealed acceptance without judgment significantly mediated the relation between DBT-ST and change in frequency of NSSI.