Objective: The aim of this article is to examine whether standard Dialectical Behavior Therapy (DBT) (1) can be successfully implemented in a mixed population of borderline patients with or without comorbid substance abuse (SA), (2) is equally efficacious in reducing borderline symptomatology among those with and those without comorbid SA, and (3) is efficacious in reducing the severity of the substance use problems.
Method: The implementation of DBT is examined qualitatively. The impact of comorbid SA on its efficacy, as well as on its efficacy in terms of reducing SA, is investigated in a randomized clinical trial comparing DBT with treatment-as-usual (TAU) in 58 female borderline patients with (n = 31) and without (n = 27) SA.
Results: Standard DBT can be applied in a group of borderline patients with and without comorbid SA. Major implementation problems did not occur. DBT resulted in greater reductions of severe borderline symptoms than TAU, and this effect was not modified by the presence of comorbid SA. Standard DBT, as it was delivered in our study, however, had no effect on SA problems.
Conclusions: Standard DBT can be effectively applied with borderline patients with comorbid SA problems, as well as those without. Standard DBT, however, is not more efficacious than TAU in reducing substance use problems. We propose that, rather than developing separate treatment programs for dual diagnosis patients, DBT should be "multitargeted." This means that therapists ought to be trained in addressing a range of severe manifestations of personality pathology in the impulse control spectrum, including suicidal and self-damaging behaviors, binge eating, and SA.