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Treatment of Monozygotic Twins with Obsessive Compulsive Disorder Using Cognitive Therapy and Exposure with Ritual Prevention

  • Michael P. Twohig (a1), Maureen L. Whittal (a2) and Katherine A. Peterson (a1)

Background: Assessment and treatment of cohabiting monozygotic (MZ) twins with obsessive compulsive disorder (OCD) is a possible challenge for clinical psychologists. Aims: This study aims to present a detailed history of two sets of cohabiting MZ twins with OCD, and describe the adaption of cognitive behavior therapy in their treatments. Method: Two sets of cohabiting MZ twins completed a structured intake and the Yale Brown Obsessive Compulsive Scale as well as measures of depression, anxiety, a measure of obsessive beliefs, and thought action fusion. One set received cognitive behavior therapy and exposure with ritual prevention (ERP) simultaneously and the other received ERP separately. Pre-, post-treatment and follow-up assessments occurred for both sets of twins. Results: All four individuals showed notable decreases in OCD, and results were maintained for three of the four participants at follow-up points. Conclusions: This study highlights the developmental course of OCD that can occur in cohabiting twins, and the clinical adaption that may be necessary.

Corresponding author
Reprint requests to Michael P. Twohig, Utah State University, 2810 Old Main Hill, Logan, UT 84322, USA. E-mail: An extended version of the measures section, description of participants, and treatment procedures is available in the table of contents for this issue: or from the authors.
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Baxter, L. R. JR., Schwartz, J. M., Bergman, K. S., Szuba, M. P., Guze, B. H., Mazziotta, J. C., Alazraki, A., Selin, C. E., Ferng, H. K., Munford, P. and Phelps, M. E. (1992). Caudate glucose metabolic rate changes with both drug and behavior therapy for obsessive compulsive disorder. Archives of General Psychiatry, 49, 681689.
Henin, A. and Kendall, P. C. (1997). Obsessive-compulsive disorder in childhood and adolescence. Advances in Clinical Child Psychology, 19, 75131.
Nestadt, G., Samuels, J., Riddle, M., Bienvenu, J. O., Liang, K., LaBuda, M., Walkup, J., Grados, M. and Hoehn-Saric, R. (2000). A family study of obsessive-compulsive disorder. Archives of General Psychiatry, 57, 358363.
Salkovskis, P. M. (1985). Obsessional-compulsive problems: a cognitive-behavioral analysis. Behaviour Research and Therapy, 23, 571583.
Steketee, G. (1993). Social support and treatment outcome of obsessive-compulsive disorder at 9-month follow-up. Behavioral Psychotherapy, 21, 8195.
Van Grootheest, D. S., Cath, D. C., Beekman, A. T. and Boomsma, D. I. (2005). Twin studies in obsessive-compulsive disorder: a review. Twin Research and Human Genetics, 8, 450458.
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Behavioural and Cognitive Psychotherapy
  • ISSN: 1352-4658
  • EISSN: 1469-1833
  • URL: /core/journals/behavioural-and-cognitive-psychotherapy
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