Is Mentalization a Common Process Factor in Transference-Focused Psychotherapy and Dialectical Behavior Therapy Sessions? Geoff Goodman Long Island University Transference-focused psychotherapy (TFP) and dialectical behavior therapy (DBT) are 2 treatment models designed to treat patients with borderline personality disorder (BPD). Although originating in separate theoretical orientations, TFP and DBT have been effective in treating BPD patients. Reflective functioning (RF), defined as interpreting the behaviors of self and others as motivated by the underlying mental states of self and others, has been suggested as an effective therapeutic process common to all BPD treatment models. Expert raters provided TFP and DBT prototypes as well as a prototype of RF process using the Psychotherapy Process Q-Set. Three hypotheses were tested: (1) The TFP prototype would be positively correlated with a previously constructed psychodynamic therapy (PDT) prototype and not with a previously constructed cognitive– behavioral therapy (CBT) prototype or the DBT prototype, (2) the DBT prototype would be positively correlated with the CBT prototype and not with the PDT prototype, and (3) the RF process prototype would be positively correlated with both the TFP and DBT prototypes. The TFP and DBT prototypes loaded onto 2 independent factors. The RF process prototype loaded onto both factors. The TFP prototype was positively correlated with the PDT prototype and not with the CBT or DBT prototypes. The DBT prototype was positively correlated with both the CBT and PDT prototypes. The RF process prototype was highly correlated with all prototypes. It is argued that enhancing RF in BPD patients is an implicit process inherent to TFP and DBT and should be explicitly acknowledged. Keywords: psychotherapeutic processes, transference-focused psychotherapy, dialectical behavior therapy, reflective functioning, common factors Transference-focused psychotherapy (TFP; Clarkin, Yeomans, & Kernberg, 2006) and dialec- tical behavior therapy (DBT; Linehan, 1993) are two empirically supported treatment models spe- cifically designed to treat patients diagnosed with borderline personality disorder (BPD). Both treat- ment models have accumulated evidence support- ing their efficacy and effectiveness in treating this population, yet no empirical studies have identi- fied their respective active ingredients. Recently, Bateman and Fonagy (2004a) hypothesized that enhancing mentalization is the common process factor inherent to all treatment models designed to treat BPD patients. This study tested this hypoth- esis by (a) identifying the similarities and differ- ences of TFP and DBT processes in prototypical sessions and (b) determining whether mentaliza- tion might be a common process factor in these two treatment models. Transference-Focused Psychotherapy Empirical evidence in support of the effec- tiveness and efficacy of TFP, a psychodynamic treatment model for BPD patients, has been gradually accumulating (Clarkin et al., 2001; This article was published Online First May 27, 2013. This research was supported by a generous grant from the International Psychoanalytical Association Research Advi- sory Board. The three TFP experts, three DBT experts, and three RF experts deserve special recognition for offering their valuable time to complete the prototypical Q-sorts. I thank Stuart Ablon, who graciously provided his compos- ited PDT and CBT prototypical Q-sorts, and Valeda Dent, who reproduced Tables 1 and 2 in Microsoft Word. Gia- como Buscaino and Silvia Fiammenghi provided expert coding assistance with the three founder-conducted psycho- therapy sessions, and Tina Lo and Brittany Hulse checked references. I gratefully acknowledge the assistance of Mar- cia Miller, chief librarian at Weill Medical College of Cor- nell University–Westchester Division, in locating and ob- taining reference materials. Correspondence concerning this article should be ad- dressed to Geoff Goodman, Clinical Psychology Doctoral Program, Long Island University, 720 Northern Boulevard, Brookville, NY 11548. E-mail: ggoodman@liu.edu This document is copyrighted by the American Psychological Association or one of its allied publishers. This article is intended solely for the personal use of the individual user and is not to be disseminated broadly. Journal of Psychotherapy Integration © 2013 American Psychological Association 2013, Vol. 23, No. 2, 179 –192 1053-0479/13/$12.00 DOI: 10.1037/a0032354 179