Paranoia in the Nonclinical Population Rhani Allen-Crooks MA Thesis submitted to the University of London for the degree of Doctor of Philosophy Department of Psychology Royal Holloway, University of London June 2012 1 Acknowledgements This thesis was made possible by the help and support of many individuals, to each of whom I am extremely grateful. However, I would like to pay special thanks to a few people without whom the experience would not have been as enriching or enjoyable. I am grateful to my primary supervisor, Dr Lyn Ellett for all her help, support and guidance over the past three years. She has always been available in times of need and has supervised and taught me with equal measures of patience and enthusiasm. I would also like to express my gratitude to Professor Paul Chadwick, whose advice and insights were invaluable, and whose contributions at our meetings together always left me feeling encouraged and motivated to press on with the research. Special thanks must also be given to my colleague Dr Sam McCormick; proof reader, personal advisor, motivation coach, and friend. Finally, I would like to thank my husband Lee, and children Jobe and Lily, who supported me with grace and understanding whilst I spent three years intently looking at something I found quite interesting. 2 Declaration of Authorship I Rhani Allen-Crooks hereby declare that this thesis and the work presented in it is entirely my own. Where I have consulted the work of others, this is always clearly stated. Signed: ______________________ Date: ________________________ 3 Abstract A growing body of research demonstrates that paranoia is common in the general population. Four studies are presented that investigate factors associated with paranoia and naturalistic change in non-clinical groups. First, two experimental studies examine paranoia in the context of the Prisoner’s Dilemma Game (PDG), an interpersonal research paradigm, where two players have the choice to cooperate or compete with each other. The dominant and rational choice for both players is to compete, however each players’ individual reward would be greater if they both played cooperatively. Study 1 found that higher state paranoia was associated with the choice to compete. However the competitive choice can be selected due to distrust of the other player, or in order to maximise personal gain. The second experimental study employs a Three-Choice version of the PDG (PDG-Alt) that includes the option to withdraw, the rational choice when distrust of the other player is high. Higher state paranoia was associated with the withdrawal choice. These studies conclude that the withdrawal choice in the PDG –Alt provides a potential behavioral marker of state paranoia. Second, two studies examine naturalistic change in nonclinical paranoia. Idiosyncratic accounts of a single past paranoid experience are elicited and variations in dimensions known to be important in clinical paranoia are examined. Results show that levels of preoccupation, distress, impact on well being and conviction that harm was intentional significantly reduce over time. However the amount of time passed since the experience occurred is not significantly associated with level of change. Finally, in Study 4 a qualitative investigation is presented that identifies themes associated with change in nonclinical experiences of paranoia. The thesis concludes with a discussion of the theoretical, clinical and research implications of the findings. 4 Table of Contents Abstract .................................................................................................................................... 4 1 Chapter One - Introduction .............................................................................. 15 1.1 Overview of Introduction Chapter .................................................................................. 15 1.2 What is Paranoia? ........................................................................................................... 16 1.2.1 Historical Accounts .............................................................................................. 16 1.2.2 Operational Accounts of Paranoia ...................................................................... 16 1.2.3 Problems with Operational Accounts ................................................................. 18 1.3 Freeman and Garety’s Definition .................................................................................... 19 1.3.1 Current Usage of the Term ................................................................................. 21 1.4 Current Models of Paranoia ............................................................................................ 21 1.4.1 Paranoia as Defence, and Emotional Consistent Accounts. ............................... 22 1.4.2 Freeman’s Emotional Consistent Account .......................................................... 24 1.4.3 Poor Me and Bad Me Paranoia ........................................................................... 25 1.5 Continuum views of Paranoia ......................................................................................... 27 1.5.1 The Phenomenological and Vulnerability Distinction ......................................... 29 1.5.2 The Continuous and Quasi-continuous Distinction ............................................ 29 1.5.3 Support for the Continuum Approach ................................................................ 30 1.6 Prevalence Studies of Psychosis in Nonclinical Populations ........................................... 31 1.6.1 Paranoia in Nonclinical Populations .................................................................... 32 5 1.6.2 Criticisms of Prevalence Research ...................................................................... 41 1.7 Questionnaire based Research ....................................................................................... 42 1.7.1 Questionnaire Measures of Paranoia in Nonclinical Groups ............................. 44 1.7.2 Social Cognitive Biases and Nonclinical Paranoia ............................................... 47 1.7.3 Criticisms of Self Report Data ............................................................................. 48 1.8 Experimental Approaches to Paranoia ........................................................................... 50 1.8.1 The Camera Paradigm ......................................................................................... 50 1.8.2 Virtual Reality Studies ......................................................................................... 53 1.8.3 Green, Freeman & Kuipers, 2011 ........................................................................ 55 1.8.4 Limitations with Experimental Approaches to Date ........................................... 57 1.9 Research Questions & Implications ................................................................................ 58 1.10 Thesis Plan ....................................................................................................................... 59 2 Chapter Two – Prisoner’s Dilemma Game and Paranoia ............ 62 2.1 Introduction .................................................................................................................... 62 2.1.1 The Prisoner’s Dilemma Game (PDG) ................................................................. 63 2.1.2 Iteration vs. One Shot Games ............................................................................ 66 2.1.3 PDG as a Tool in Psychological Research ............................................................ 67 2.1.4 Prisoners Dilemma and Paranoia ........................................................................ 67 2.2 Study 1 – Two-Choice Prisoner’s Dilemma Game and Paranoia ..................................... 67 2.2.1 Rationale ............................................................................................................. 67 6 2.2.2 Design .................................................................................................................. 68 2.2.3 Participants ......................................................................................................... 68 2.2.4 Measures ............................................................................................................. 69 2.2.5 Procedure ............................................................................................................ 73 2.2.6 Results ................................................................................................................. 77 2.2.7 Discussion ............................................................................................................ 81 2.3 Study 2 – A Three-Choice version of the Prisoner’s Dilemma (PDG- Alt) ....................... 82 2.3.1 Rationale ............................................................................................................. 82 2.3.2 Power Analysis .................................................................................................... 83 2.3.3 Participants ......................................................................................................... 84 2.3.4 Measures and Procedure .................................................................................... 84 2.3.5 Results ................................................................................................................. 85 2.3.6 Discussion ...........................................................................................................