Objective Investigate influence and change of self-directedness (SD) in 
Dialectical-Behavior Therapy (DBT) for 26 female outpatients with borderline 
personality disorder (BPS). Method Variance analyses are used to evaluate 
psychopathology and interpersonal problems in 2 subgroups (low vs. high SD) with 
questionnaires at 3 measuring times over the period of 1 year. Results Low SD 
was associated with higher psychopathology, more interpersonal problems and 
lower symptomreduction. Over time of intervention the SD of all patients 
improved significantly. Conclusion DBT strengthens the SD of patients with BPD. 
A screening of SD before intervention, and systematic support should be 
considered.