Do treatment outcomes differ after 3 months DBT inpatient treatment based on borderline personality disorder subtypes?

Heterogeneity in borderline personality disorder (BPD) drives the search for BPD subtypes to optimize the assessment and treatment of these patients. Therefore, the aims of the present study were (1) to replicate previously identified BPD subtypes based on reactive and regulative temperament; (2) to compare them on symptomatology and coping; and (3) to investigate whether these subtypes show different treatment responses after 3 months of inpatient dialectical behaviour therapy (DBT). A total of 145 BPD inpatients were assessed by means of measures of temperament, symptomatology and coping. Through model-based clustering on the Behavioural Inhibition and Behavioural Activation Scales (BISBAS) and Effortful Control Scale (ECS), we identified three BPD subtypes: an Emotional/Disinhibited subtype (15%, high BAS and low ECS); a Low Anxiety subtype (41%, low BIS) and an Inhibited subtype (44%, low BAS). After 3 months of DBT, 75 patients completed the measures for a second time. Repeated measure ANOVAs demonstrated a general improvement on all symptoms and coping strategies. In addition, the BPD subtypes showed trajectory differences in clinical and borderline specific symptomatology and dissociation. These findings indicate that BPD subtypes based on temperament demonstrate different treatment responses, which can contribute to the search of more BPD subtype tailored treatment interventions.