SPE C I AL S E R I E S SUBT Y PES OF OBSE S S I VE -C O M PU L S I VE D I S O RD E R
Introduction Jonathan Abramowitz, Mayo Clinic Dean McKay, Fordham University Steven Taylor, University of British Columbia
An accumulating body of research suggests that obsessivecompulsive disorder (OCD) is a heterogeneous condition, yet there is not yet a consensus on how best to conceptualize subtypes or dimensions of the disorder. This special series considers theoretical and practical issues pertaining to OCD subtypes. New possibilities for conceptualizing differences among OCD patients are considered, and avenues for treating different presentations of obsessions and compulsions are discussed. Treatment programs continue to be refined and outcome studies continue to demonstrate that tailoring cognitive-behavioral treatment toward specific presentations of OCD (e.g., contamination fears, severe obsessions) represents the future of OCD treatment. The articles in this special series are intended to further efforts to consider ways of better understanding the heterogeneity of OCD.
According to the Diagnostic and Statistical Manual (DSM-IV-TR; American Psychiatric Association, 2000), obsessive-compulsive disorder (OCD) is comprised of obsessions, compulsions, or (most commonly) both. This description suggests that OCD is homogeneous, which is what one would expect if OCD represents a unitary syndrome (cf. Robins & Guze, 1970). Whereas it is accepted practice to describe disorders in homogeneous terms, as research accumulates, greater complexity emerges. Clinicians who regularly treat patients with OCD readily suggest that subtypes must exist. Most research on subtypes has been based on symptom models and analyses of
Editor’s Note: Guest editors did not serve as action editors or reviewers for papers on which they were authors. Address correspondence to Jonathan S. Abramowitz, Ph.D., Mayo Clinic, OCD/Anxiety Disorders Program, 200 First Street SW, Rochester, MN 55905; e-mail:
[email protected]. BEHAVIOR THERAPY
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symptom checklists (McKay et al., 2004). As we have recently pointed out, this research has determined that OCD is comprised of multiple symptom dimensions. The symptom dimensions typically identified are: (a) obsessions (aggressive, sexual, religious, or somatic) and checking compulsions; (b) symmetry obsessions and ordering, counting, and repeating compulsions; (c) contamination obsessions and cleaning compulsions; and (d) hoarding obsessions and collecting compulsions (Taylor, 2005). These dimensions, however, are not distinct subtypes, and OCD sufferers frequently exhibit symptoms in more than one area (i.e., aggressive obsessions and contamination obsessions). While the research on dimensions of OCD has been primarily based on symptoms, other models exist. For example, distinctions have been identified between individuals who have OCD with comorbid tics compared to those without tics (Leckman et al., 2000). Recent research has also identified subtypes with and without prominent cognitive distortions typically associated with OCD (Taylor, Abramowitz, et al., in press). The importance of determining whether subtypes exist, what models are best for assessing the presence of subtypes, and their unique characteristics bears on conceptualization and treatment. It is well accepted that treatment for individual symptoms of OCD requires specific tailoring of interventions. As a consequence, there have already been substantial efforts to validate cognitive-behavioral treatments for symptoms of OCD, such as obsessions without compulsions (Freeston et al., 1997) and hoarding (Frost & Hartl, 1996). These symptoms are dimensions within the diagnosis of OCD (McKay et al., 2004) and point to the need to determine subtypes in order to develop more effective treatment procedures. Most of the contributors to this special series on OCD subtypes are members of a larger, international group of investigators, the Obsessive Compulsive Cognitions Working Group (OCCWG). The work-
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ing group consists of over 40 OCD researchers who have been pursuing a number of collaborative projects, including the development of instruments to measure dysfunctional beliefs in OCD (e.g., OCCWG, 2003, 2005). The presence of this collaborative network has made it relatively easy for subgroups of researchers to pursue special interests. Accordingly, a subgroup of OCCWG investigators recently initiated a series of projects aimed at examining the concept of OCD subtypes (e.g., McKay et al., 2004; Taylor, Abramowitz, et al., in press). The present special series is an extension of these investigative efforts. As such, the series illustrates how fruitful research programs can be developed and pursued by organizing research consortiums such as the OCCWG. In addition to facilitating data collection, such as the collection of data from hundreds of OCD patients (e.g., OCCWG, 2003), such consortia facilitate the lively exchange of ideas among investigators with diverse research backgrounds and clinical experiences. The articles included in this series each address the issue of OCD subtypes from a different, yet related perspective. In the first article, Radomsky and Taylor (2005; this issue) discuss the pitfalls and potentials of efforts to identify OCD subtypes. Although they are optimistic that the conceptualization of subtypes will improve the assessment and treatment of OCD, they caution that clinicians and researchers should heed a number of pertinent theoretical and practical considerations. In the second article, Haslam and colleagues (2005; this issue) extend the existing body of research by applying taxometric analysis to examine the categorical versus dimensional status of possible OCD subtypes. Their work represents an advance over existing studies as it considers both overt symptom-based subtypes (e.g., contamination, checking, obsessionality) and cognitionbased subtypes (e.g., responsibility and threat estimation, perfectionism and tolerance of ambiguity, importance/control of thoughts). As the ultimate goal of developing subtyping schemes is to improve the treatment of OCD, the third article, by Sookman et al. (2005; this issue), considers issues related to the clinical management of identified OCD subtypes. These authors describe specific cognitive and behavioral therapy techniques that show promise for addressing phenomenological idiosyncrasies characteristic of the different OCD symptom dimensions. An excellent example is the use of loop-tape imaginal exposure for severe obsessional thoughts (Freeston et al., 1997). In the final article in this series, Clark (2005; this issue) provides a commentary on the three articles. He concludes by proposing an alternative to the categorical subtyping approaches offered in the
three papers; one based on some form of profiling that recognizes the dimensional nature of OCD symptom and cognition variables. Clark’s views are partially consistent with recent profiling analyses (Taylor, Abramowitz, et al., in press) in which clusters of OCD patients were identified, differing in terms of their profiles of OC-related dysfunctional beliefs and symptoms. Taylor, Abramowitz, et al. found that one group of OCD patients, compared to various control groups, did not have abnormally elevated scores on measures OC-related dysfunctional beliefs. In other words, scores on measures of OC-related beliefs failed to distinguish OCD patients from other groups, thereby challenging the view that these people developed OCD because of unusually strong OC-related beliefs, such as beliefs concerning perfectionism and inflated personal responsibility. These results, however, are consistent with the view that dysfunctional beliefs may play a role in only some types of OCD (Taylor, McKay, & Abramowitz, 2005). Such findings merit replication and further investigation, because they suggest the possibility of developing an etiologically based subtyping scheme for classifying the various forms of OCD. We hope the articles that follow will contribute to future research and improve the clinical management of OCD. References American Psychiatric Association. (2000). Diagnostic and statistical manual of mental disorders (4th ed., text revision). Washington, DC: Author. Clark, D. A. (2005). Lumping versus splitting: A commentary on subtyping in OCD (2005). Behavior Therapy, 36, 401–404. Freeston, M. H., Ladouceur, R., Gagnon, F., Thibodeau, N., Rheume, J., Letarte, H., & Bujold, A. (1997). Cognitive behavioral treatment of obsessive thoughts: A controlled study. Journal of Consulting and Clinical Psychology, 65, 405–413. Frost, R. O., & Hartl, T. L. (1996). A cognitive behavioral model of compulsive hoarding. Behaviour Research and Therapy, 34, 341–350. Haslam, N., Williams, B. J., Kyrios, M., McKay, D., & Taylor, S. (2005). Subtyping obsessive-compulsive disorder: A taxometric analysis. Behavior Therapy, 36, 381–391. Leckman, J. F., McDougle, C. J., Pauls, D. L., Peterson, B. S., Grice, D. E., King, R. A., Scahill, L., Price, L. H., & Rasmussen, S. A. (2000). Tic-related versus non-tic-related obsessive-compulsive disorder. In W. K. Goodman, M. V. Rudorfer, & J. D. Maser (Eds.), Obsessive-compulsive disorder: Contemporary issues in treatment (pp. 43–68). Mahwah, NJ: Erlbaum. McKay, D., Abramowitz, J. S., Calamari, J., Kyrios, M., Sookman, D., Taylor, S., & Wilhelm, S. (2004). A critical evaluation of obsessive-compulsive disorder subtypes: Symptoms versus mechanisms. Clinical Psychology Review, 24, 283–313. Obsessive Compulsive Cognitions Working Group. (2003). Psychometric validation of the Obsessive Beliefs Questionnaire and the Interpretation of Intrusions Inventory: Part 1. Behaviour Research and Therapy, 41, 863–878.
introduction to the special series Obsessive Compulsive Cognitions Working Group. (2005). Psychometric validation of the Obsessive Beliefs Questionnaire and the Interpretation of Intrusions Inventory: Part 2. Behaviour Research and Therapy, 43, 1527–1542. Radomsky, A., & Taylor, S. (2005). Subtyping OCD: Prospects and problems. Behavior Therapy, 36, 371–379. Robins, E., & Guze, S.B. (1970). Establishment of diagnostic validity in psychiatric illness: Its application to schizophrenia. American Journal of Psychiatry, 126, 983–987. Sookman, D., Abramowitz, J. S., Calamari, J. E., Wilhelm, S., & McKay, D. (2005). Subtypes of obsessive-compulsive disorder: Implications for specialized cognitive behavior therapy. Behavior Therapy, 36, 393–400. Taylor, S. (2005). Dimensional and subtype models of OCD. In
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J. S. Abramowitz & A. C. Houts (Eds.), Concepts and controversies in obsessive-compulsive disorder (pp. 27–41). New York: Springer. Taylor, S., Abramowitz, J. S., McKay, D., Calamari, J. E., Sookman, D., Kyrios, M., Wilhelm, S., & Carmin, C. (in press). Do dysfunctional beliefs play a role in all types of obsessivecompulsive disorder? Journal of Anxiety Disorders. Taylor, S., McKay, D., & Abramowitz, J. S. (2005). Is obsessive-compulsive disorder a disturbance of security motivation? Comment on Szechtman and Woody (2004). Psychological Review, 112, 650–657. R e c e i v e d : September 21, 2004 Ac c e p t e d : January 5, 2005
