The present study is the first to examine OCPD as a specific predictor of EX/RP outcome. Over a third of our primary OCD sample met criteria for OCPD. Our findings show that both OCPD diagnosis and greater OCPD severity at baseline predicted worse EX/RP outcome, controlling for baseline OCD severity, Axis I and II comorbidity, prior SRI treatment, quality of life, and gender. When the individual OCPD criteria were tested separately, only perfectionism predicted worse EX/RP outcome, over and above the previously mentioned covariates.
Our results are consistent with several studies that show that OCD patients with a comorbid personality disorder are less responsive to CBT (AuBuchon & Malatesta, 1994
; Steketee, Chambless, & Tran, 2001
). However, the sole prior study to examine the effect of specific personality disorders on CBT outcome for OCD utilized an individually tailored multimodal CBT and found that only baseline schizotypal and passive-aggressive traits were predictive of later treatment failure at trend level (Fricke, et al., 2006
). The present investigation improves upon this prior work by: (1) examining the specific effect of OCPD (both diagnosis and severity) on outcome; (2) utilizing a highly structured, intensive, manualized (with quality control) version of EX/RP; (3) studying a sample with a higher rate of comorbid OCPD; and (4) assessing personality disorders with a structured diagnostic interview.
Our findings suggest that comorbid OCPD impedes EX/RP outcome in OCD. One possible explanation for this finding is that the interpersonal dysfunction associated with OCPD (Costa, et al., 2005
) may interfere with the collaborative nature of this treatment and hamper working alliance between therapist and patient, thereby affecting engagement in and adherence to EX/RP assignments. Therapists may require more time to create a therapeutic relationship with these patients since individuals with OCPD have been described as having difficulty with trust and commitment (Gibbs & Oltmanns, 1995
). As a result, patients with comorbid OCPD may need a longer, more comprehensive treatment than standard EX/RP (e.g., with adjunctive interventions to address interpersonal functioning).
Our data further suggest that one of the most important aspects of OCPD for predicting poorer EX/RP outcome for OCD is perfectionism. The presence of this single OCPD trait was as predictive of outcome as the total number of OCPD criteria endorsed. Perfectionism is one of the most prevalent and stable OCPD features (McGlashan, et al., 2005
) and has consistently emerged as an important component in factor analytic studies of OCPD (Ansell, et al., 2010
; Ansell, Pinto, Edelen, & Grilo, 2008
; Hummelen, Wilberg, Pedersen, & Karterud, 2008
Our finding that perfectionism negatively impacted EX/RP outcome is consistent with treatment studies of depression and anorexia nervosa in which the trait was also associated with poorer treatment outcome. In the Treatment of Depression Collaborative Research Program, perfectionism negatively impacted treatment outcome, regardless of treatment modality (Blatt, Quinlan, Pilkonis, & Shea, 1995
). Higher pretreatment perfectionism was associated with lower treatment gain and lower patient satisfaction with treatment (Blatt, et al., 1995
), as well as less satisfying interpersonal relationships, fewer coping skills, and greater self-criticism (Blatt, Zuroff, Bondi, Sanislow, & Pilkonis, 1998
). A systematic review of the anorexia nervosa literature indicates a negative impact for perfectionism in both longitudinal studies of course and acute treatment trials (Crane, Roberts, & Treasure, 2007
). Some explanations for the negative impact of perfectionism on outcome include difficulty developing strong therapeutic alliances (Zuroff, et al., 2000
) and a heightened sense of failure in response to slow treatment gains (Blatt, et al., 1998
In the context of EX/RP, perfectionism can interfere in treatment outcome in various ways, including the following scenarios: (1) Patient tries “too hard” to do the treatment “perfectly” and fixates (“gets stuck”) on the specifics of EX/RP technique, perseverating on whether or not he/she is doing the treatment “correctly,” as opposed to focusing on the overall cognitive-behavioral model of OCD and the purpose of doing exposures; (2) Patient avoids or does not adhere to between-session EX/RP assignments for fear of not doing them perfectly. (OCD patients with a need for the “just right”/perfect feeling before completing an action may not comply with EX/RP assignments in order to avoid the discomfort associated with “incompleteness.”); (3) Patient adopts a narrow view of EX/RP assignments and does not attempt to generalize to related situations for fear of failure or discomfort; (4) Patient gives up on treatment or withdraws effort if he/she believes progress is suboptimal (“If the treatment is not going perfectly, why should I bother at all?”).
Recently a focused, brief, manualized cognitive-behavioral intervention has shown promise in reducing clinical perfectionism (with a large effect size) and reductions were maintained at follow-up (Riley, Lee, Cooper, Fairburn, & Shafran, 2007
). It may be useful to incorporate such an intervention into EX/RP for OCD in patients with prominent perfectionism that interferes with treatment. The treatment consists of four elements originally developed by Fairburn, Cooper, and Shafran (2003)
: (1) identifying perfectionism as a problem and understanding how it is maintained (e.g., repeated performance checking or over-training); (2) conducting behavioral experiments to learn more about the nature of the patient’s perfectionism and alternative ways of coping (e.g., the impact of checking repeatedly vs. checking only occasionally); (3) applying psychoeducation and cognitive restructuring (in combination with behavioral experiments) to modify personal standards, self-criticism, and cognitive biases such as selective attention to perceived failure; and (4) broadening the patient’s capacity for self-evaluation, by identifying and adopting alternative cognitions and behaviors.
By focusing on patients that have already received an adequate SRI trial, the study was designed to recruit patients similar to those seen in routine clinical practice. We believe our findings are broadly applicable to OCD patients on SRIs who seek to augment their treatment with EX/RP. A limitation of the present study is the reliance on DSM-IV criteria for OCPD. Grilo et al. (2001
) found the psychometric strength and diagnostic efficiencies of these criteria to vary, with some criteria having questionable utility. DSM-IV also does not adequately capture all problematic aspects of OCPD, including its cognitive, affective, and interpersonal domains. Moreover, the criteria-level exploratory analyses employed in this study were problematic in that they were based on individual dichotomous (present/absent) items. Future studies of OCPD would benefit from a more comprehensive and dimensional characterization of the disorder and its components. Given our findings, we also recommend further research with more sensitive dimensional measures of perfectionism to explore the impact of this trait on treatment outcome in patients with versus without OCPD. A dimensional approach is emphasized in the proposed personality disorder revisions for DSM-5 (Skodol, et al., 2011
). For example, the new system would allow clinicians to rate the degree to which a patient matches narrative descriptions of personality disorder types (including OCPD) and the degree to which particular pathological personality traits (including perfectionism) describe the patient.
In summary, in this sample of OCD patients who were stable on SRIs and received EX/RP treatment, both OCPD diagnosis and greater OCPD severity predicted worse EX/RP outcome, controlling for other known predictors of EX/RP outcome. Of all the OCPD criteria, the presence of perfectionism was most strongly associated with poor EX/RP outcome. Our results underscore the importance of considering the impact of personality pathology on the course and treatment of Axis I disorders. Future studies should examine whether OCPD has similar effects on EX/RP outcome in non-medicated samples. Incorporating interventions that directly address OCPD-related traits, especially perfectionism, into EX/RP would be one way to personalize care and potentially improve treatment outcome.