Organizing borderline personality disorder symptoms, childhood maltreatment experiences, and posttraumatic stress disorder symptoms: Do unique subgroups exist and influence dialectical behaviour therapy outcomes?

BPD is characterized by dysregulation in emotions, behaviours, relationships, identity, and thoughts, as well as frequent engagement in self-injury. Childhood maltreatment experiences (including childhood trauma) and Posttraumatic Stress Disorder (PTSD) symptoms are highly associated with BPD, and predict worse BPD-treatment responses. However, it remains unclear whether distinct childhood maltreatment-related experiences and PTSD symptoms uniquely covary with BPD symptoms, or whether such covariation differentially predicts BPD-relevant treatment outcomes. The present study thus examined whether in trauma-exposed individuals with BPD receiving standard Dialectical Behaviour Therapy (DBT): 1) unique subgroups of distinct BPD symptoms, childhood maltreatment experiences, and PTSD symptoms exist; and 2) whether identified subgroups differentially predict BPD-relevant treatment outcomes. Latent Profile Analysis revealed three distinct classes: Low, Moderate, and High Maltreatment. Classes stratified on the bases of severity of childhood maltreatment experiences and PTSD symptoms, though BPD symptoms did not differentiate classes. Within each class, childhood emotional abuse and neglect, and some PTSD symptoms (e.g., intense negative emotion, emotional reactivity) were elevated in severity compared to other forms of childhood maltreatment and PTSD symptoms. Generalized estimating equation models also revealed that the High Maltreatment class exhibited a slower decline in frequency of self-injury and PTSD symptom severity compared to the Moderate and Low Maltreatment Classes. This study suggests that individuals with more severe childhood emotional abuse and neglect, and higher severity PTSD symptoms, may require additional or alternative (e.g., trauma-focused) interventions to standard DBT for self-injury and PTSD symptom severity to improve.