Dialectical Behavior Therapy Versus General Psychiatric Management in the Treatment of Borderline Personality Disorder
To the Editor: We read with interest the article by Shelley F. McMain, Ph.D., et al. (1), published in the December 2009 issue of the Journal. It is my opinion that additional information would have clarified the primary study findings. The authors reported that there was no difference between treatment groups in primary outcomes of frequency and maximum severity of nonsuicidal self-injurious behavior, presenting a group contrast odds ratio and coefficient, respectively, without confidence intervals. When no difference is found between two potentially active treatments, confidence intervals inform the question of whether a study has either demonstrated that the treatments are equivalent or failed to demonstrate that one treatment is superior (2). In the former case, confidence intervals for a group contrast are narrow enough to exclude clinically meaningful differences (defined by the authors as at least a 20% difference in the rate of self-injurious behavior), while in the latter case confidence intervals include both clinically meaningful and nonmeaningful differences. Confidence intervals are therefore important in understanding the authors' conclusion that study results "legitimize the recommendations of the APA practice guideline on the management of borderline personality disorder" (1, p. 1372) using general psychiatric management. This conclusion would be supported most strongly by the finding that general psychiatric management is either equivalent or not inferior to dialectical behavior therapy, a treatment with demonstrated efficacy (3, 4).
The reader would also benefit from clarification of whether baseline characteristics presented in Table 2 rather than Table 1, particularly baseline rates of suicidal and self-injurious episodes (dialectical behavior therapy: 20.94 versus general psychiatric management: 32.19), were tested for group differences.
1 : A randomized trial of dialectical behavior therapy versus general psychiatric management for borderline personality disorder. Am J Psychiatry 2009; 166:1365–1374 Link, Google Scholar
2 : Clinical trials design lessons from the CATIE study. Am J Psychiatry 2009; 166:1222–1228 Link, Google Scholar
3 : Dialectical behaviour therapy for women with borderline personality disorder: 12-month, randomised clinical trial in The Netherlands. Br J Psychiatry 2003; 182:135–140 Crossref, Medline, Google Scholar
4 : Cognitive-behavioral treatment of chronically parasuicidal borderline patients. Arch Gen Psychiatry 1991; 48:1060–1064 Crossref, Medline, Google Scholar