Compulsive Disorder

A thesis submitted in fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY, Discipline of Psychiatry, The University of Sydney. 7th April 2012. SYMPTOM-BASED SUBTYPES OF OBSESSIVE- COMPULSIVE DISORDER. Student: Dr Vlasios Brakoulias MB,BS (Hon), M(Psychiatry), FRANZCP Clinical lecturer and Staff Specialist in Psychiatry Department of Psychiatry Nepean Clinical School Level 5 South Block Nepean Hospital PO Box 63 Penrith NSW 2751 e-mail: [email protected] Tel: 61 2 4734 2585 Fax: 61 2 4734 3343 Research Supervisor: A/Professor Vladan Starcevic Associate Professor and Department Head Department of Psychiatry Nepean Clinical School Nepean Hospital Associate Research Supervisor: Professor Philip Boyce Professor and Department Head Department of Psychiatry Western Clinical School Westmead Hospital Institutions: Sydney West Area Health Service Department of Psychiatry University of Sydney Nepean Clinical School Nepean Anxiety Disorders Unit Date of Commencement: 5th March, 2007 on Part-time basis. Statement of Originality This thesis is submitted to The University of Sydney in fulfillment of the requirements for the Degree of Doctor of Philosophy. The work presented in this thesis is, to the best of my knowledge and belief, original. I hereby declare that I have not submitted this material either in full or in part, for a degree at this or any other institution. _____________________ ____________________ Vlasios Brakoulias Date 2 3 ABSTRACT Obsessive-compulsive disorder (OCD) is heterogeneous in its presentation and quests to clarify the best way to subtype OCD have remained elusive. This thesis aims to assess for symptom-based OCD subtypes in a sample of patients with OCD and to describe the characteristics of these OCD symptom subtypes. The methods used include principal components analysis of the results of the Yale- Brown Obsessive-Compulsive Disorder Scale – Symptom Checklist (YBOCS- SC) and the Vancouver Obsessional Compulsive Inventory (VOCI) self report obtained from a sample of 154 subjects with a primary diagnosis of OCD. Five symptom factors explained 67.9% of the variance. They were named: 1) hoarding; 2) contamination/cleaning; 3) symmetry/ordering; 4) unacceptable/taboo thoughts; and 5) doubt/checking. These factors were used as predictors of a number of systematically chosen characteristics and were subject to regression analyses. Results indicated that different OCD symptoms predicted different phenomenological characteristics, degrees of comorbidity, and different cognitive and emotional correlates. Results also indicate that psychological forms of therapy should be tailored to the patient’s prominent OCD symptoms. The study supported 5 major symptom dimensions rather than four. In particular, it revealed significant differences between unacceptable/taboo thoughts and doubt/checking. The results encourage researchers using symptom-based subtypes to continue their efforts with the hope of improving our understanding of the aetiology of these symptoms and the treatments that we provide patients with these symptoms. 4 5 OVERVIEW This thesis attempts to clarify the validity of symptom-based subtypes of obsessive-compulsive disorder. Chapter 1 provides a general overview of the diagnostic challenges that exist in the area of OCD and how researchers have attempted to understand these. In Section 1.1, the disorder currently known as OCD is described with an emphasis on the current primary focus of research in OCD, i.e. understanding its heterogeneity. In Section 1.2, the concept of the heterogeneity of OCD is expanded on with the presentation of currently popular proposals for the sub- typing of OCD. This includes an overview of the literature pertaining to the concept of obsessive-compulsive spectrum disorders and its relevance to the diagnostic conceptualization of OCD. It also includes a rationale for focusing on symptom-based subtypes. Section 1.3 describes the literature regarding psychiatric classification and diagnosis in general and Section 1.4 presents an attempt at synthesizing all proposed methods of assessing the validity of a psychiatric diagnosis whilst expanding on the components that contribute to each validating feature. In Section 1.5, these validating features are used to assess the validity of each of the proposed symptom subtypes using available literature. Section 1.6 concludes the introduction with a review of the strengths and limitations of existing studies that have attempted to assess the validity of symptom subtypes using factor analytic techniques. It also includes the rationale 6 for using an exploratory approach that assumes a dimensional model for OCD subtypes. Chapters 2 and 3 describe the aims and hypotheses of the study. These are organized according to a diagnostic validation scheme that is presented in Section 1.4. Chapter 4 describes the methods used with specific reference to factor analysis and linear and logistic regression techniques. Chapter 5 reports the results using the headings presented in Chapters 2 and 3. Chapter 6 discusses the results of this study in relation to the symptom factors presented in Chapter 5. It begins by discussing the nature of the sample and the way in which the results supported a symptom-based approach to sub-typing rather than other proposed methods. It then discusses how the results supported the reliability, validity and clinical utility of OCD symptom dimensions. The implications of the results, the strengths and limitations of the study and directions for future research are also discussed. Chapter 7 concludes the thesis. 7 8 ACKNOWLEDGEMENTS I sincerely thank my supervisor Prof Vladan Starcevic. He provided consistent, expert and high quality supervision. I am particularly grateful for his emphasis on improving my writing skills, conceptualizing the complex phenomena of belief, insight and diagnosis, and prioritizing tasks. I also thank my associate supervisor Prof Philip Boyce who greatly improved my understanding of statistical techniques used in relation to psychiatric diagnoses. I sincerely thank the research participants who volunteered their time to complete the lengthy and comprehensive assessments required for this study. I thank their families, friends and carers who assisted many of them to come to be assessed and to complete the lengthy questionnaires. I also thank the coordinators of the various support groups that referred patients to the study. In particular, Mr Colin Slocombe from the OCD support group of the OCD Sector of ACEDA in South Australia, Ms Michelle Graeber from the ARCVIC Anxiety Recovery Centre of Victoria and Ms Julie Leitch from the Anxiety Disorders Support groups of the Mental Health Association of New South Wales. I also thank the Nepean Anxiety Disorders Clinic and in particular Dr Denise Milicevic, Mr David Berle, Ms Karen Moses, and Mr Anthony Hannan, and the many Psychiatrists, General Practitioners, Psychologists and Counsellors that referred to the study. In particular, Dr Scott Blair-West of the Melbourne Clinic Private Psychiatric Hospital and coordinator for the in-patient OCD treatment program for his referrals. 9 The clinical psychologists at the Nepean Anxiety Disorders Clinic (Dr Denise Milicevic, Mr David Berle, Ms Karen Moses, and Mr Anthony Hannan) were invaluable. All assisted in recruitment, participant assessment and co-rating. They provided valuable support and constructive comments regarding the planning and progress of the study. They co-authored research papers and Mr David Berle in particular provided helpful advice with his excellent knowledge of statistical techniques used in the field and of the relevant literature. I thank Mrs Vicki Riley, our Department Secretary for her tireless efforts to coordinate phonecalls, participants bookings, reminders and mail outs. She provided support, enthusiasm and innovative ideas. I thank the Department Research Assistant Mr Peter Sammut who entered the incredible number of data, coordinated a very organized filing system, assisted with advertising, orders, copying and ethics applications. I would also like to sincerely thank Dr Andrew Martin from the Clinical Trials Centre of The University of Sydney for his tireless efforts in assisting with the complex statistical analyses of the enormous data set associated with the study. The study would not have been possible without the funding from the following grants: 1. Nepean Medical Research Foundation - $16, 925.45 2. Pfizer Neuroscience Grant Program - $22, 000.00 3. Discipline of Psychiatry Research Grant - $4, 950.00 10 I would also like to thank my family and friends for the time I took away from them as a sacrifice for science, medicine, and improved patient care. 11 PREFACE The study presented in this thesis represents research undertaken by the candidate in conjunction with other professionals and researchers within the Department of Psychiatry and the Nepean Anxiety Disorders Clinic of the Nepean Hospital. Ethics approval was granted by the Human Research Ethics Committee of the Sydney West Area Health Service Nepean campus. The candidate was involved in all aspects of the study and responsible for coordinating the study under the supervision of Prof Vladan Starcevic. The contributions of the candidate include: Planning and study design including selection of assessment tools, under the guidance of Prof Vladan Starcevic. Recruitment of patients via multiple talks to support groups, advocacy groups, community groups, general practitioners, psychiatric

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