PhD thesis

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					      The contribution of reinforcement sensitivity theory and family risk to

                   dysfunctional eating and hazardous drinking

                                    Natalie J. Loxton

                                     BPsych (Hons)

         School of Applied Psychology, Faculty of Health, Mt Gravatt Campus,

                                   Griffith University

Submitted in fulfilment of the requirements of the degree of Doctor of

Philosophy, September, 2004.

       This thesis details a continuing body of research investigating the

contribution of personality to disordered eating and alcohol abuse in young

women. There is growing evidence of high levels of reward sensitivity in women

with both disorders, and high levels of punishment sensitivity in dysfunctional

eating women. However, it is unlikely that personality alone accounts for the

development of such dysfunctional behaviour. Two studies were conducted to

further examine the contribution of reward and punishment sensitivity to these

disorders. In the first study, 443 university women completed self-report measures

of alcohol use, dysfunctional eating, reinforcement sensitivity, parental drinking,

family environment and maternal eating. Reward and punishment sensitivity were

better predictors of disordered behaviour than family factors, although maternal

dysfunctional eating significantly increased the risk of daughters’ dysfunctional

eating. Punishment sensitive daughters of bulimic mothers reported the highest

level of bulimic symptoms themselves. Punishment sensitivity also functioned as

a partial pathway variable between family risk and disordered eating. Given the

stronger contribution of personality to disordered behaviour, a second study was

conducted in which 131 women completed behavioural tasks under conditions of

reward and punishment. Performance on a computerised measure of punishment

sensitivity was associated with greater levels of dysfunctional eating but not

drinking. However, performance on a card-sorting task of reward sensitivity failed

to correlate with self-reported reward sensitivity or disordered behaviour. It was

concluded that an innate sensitivity to reward increases the risk of disorders

characterised by strong approach tendencies, whilst high punishment sensitivity,

perhaps due to a chaotic family, increases the risk of dysfunctional eating,

particularly daughters of eating disordered mothers.


This work has not previously been submitted for a degree or diploma in any

university. To the best of my knowledge and belief, the thesis contains no material

previously published or written by another person except where due reference is

made in the thesis itself.


Natalie J. Loxton

Date: 29 September 2004


       First and foremost, I wish to express my appreciation to my supervisor and

mentor, Associate Professor Sharon Dawe; over the past six years you have given

me so much more than just research training – thank you. This project would not

have been possible without your drive, guidance, and for the past year, patience. I

hope we will continue to collaborate in the years to come (I still haven’t mastered


       I also wish to thank the following people for assistance provided during

the course of this project: My associate supervisor Dr. Penny Davis for her

thorough reading of an earlier draft of this thesis. The final draft has benefited

enormously from your insightful comments. Dr. Stefano Occhipinti for feedback

on statistical decisions. Matthew Gullo and Nicholas Kambouropoulos for their

valuable discussions on the nuances of RST. Andrew Cooper for providing me

with the Q Task program code, John Winkleman for the original programming of

the Q Task, Dr. Paul Harnett for assistance with further programming

modifications, and Dr. Lynne Dawkins for providing instructions on the

construction of the CARROT. I also wish to thank the students and women from

the eating disorders support group for donating their time to participate in the

studies. Finally, I wish to thanks my parents for their love, support and

encouragement over the years.

Financial support for this project was provided via a Griffith University Women’s

Postgraduate Scholarship.

                              Table of Contents

Abstract ______________________________________________________________ ii

Declaration ___________________________________________________________iii

Acknowledgements _____________________________________________________iv

Table of Contents ______________________________________________________ v

List of figures _________________________________________________________ x

List of tables __________________________________________________________xi

CHAPTER ONE _______________________________________________________ 1

Overview and aims of the thesis ___________________________________________ 1

CHAPTER TWO ______________________________________________________ 6

Features and Prevalence of Alcohol Use Disorders And Eating Disorders __________ 6

     Alcohol Use Disorders______________________________________________ 6

          Classification of alcohol use disorders_____________________________ 6

          Continuum of alcohol-related problems____________________________ 7

          Prevalence and clinical significance of hazardous drinking ____________ 8

          Gender differences in alcohol-related problems _____________________ 9

          Etiology of alcohol use problems________________________________ 10

     Eating Disorders _________________________________________________ 12

          Classification of eating disorders ________________________________ 12

          Prevalence of eating disorders __________________________________ 14

          Gender differences in eating disorders____________________________ 15

          Continuum of Eating Disorders _________________________________ 15

          Clinical significance of subthreshold disordered eating ______________ 18

          Etiology of eating disorders ____________________________________ 20

     Co-occurrence of hazardous alcohol use and dysfunctional eating___________ 21

          Continuity of co-occurring hazardous drinking and dysfunctional

          eating _____________________________________________________ 24

          Eating disorder subtype differences in co-occurrence of alcohol

          misuse ____________________________________________________ 28

     The paradoxical comorbidity _______________________________________ 28

CHAPTER THREE ___________________________________________________ 31

Personality and addictive behaviour_______________________________________ 31

     Biopsychological models of personality _______________________________ 32

          Eysenck’s “Big Three” _______________________________________ 32

          Gray’s Reinforcement Sensitivity Theory_________________________ 35

          Cloninger’s Taxonomy _______________________________________ 45

     Evidence of impulsivity/reward sensitivity and anxiety/punishment

     sensitivity to alcohol misuse and dysfunctional eating____________________ 49

          Impulsivity/reward sensitivity and alcohol misuse __________________ 49

          Impulsivity/reward sensitivity and binge-eating/purging _____________ 54

          Impulsivity/reward sensitivity and comorbidity ____________________ 60

          Anxiety/punishment sensitivity and dysfunctional eating_____________ 61

          Anxiety/punishment sensitivity and alcohol use disorders ____________ 63

     The application of RST to hazardous drinking and dysfunctional eating______ 67

     Future directions in the study of RST in eating disorders and alcohol misuse __ 72

CHAPTER FOUR ____________________________________________________ 74

Family Factors _______________________________________________________ 74

     Family Environment ______________________________________________ 76

     Maternal disordered eating and daughters’ eating _______________________ 77

     Maternal alcohol use and daughters’ drinking __________________________ 78

    Relationships between personality and family factors on alcohol problems

    and dysfunctional eating ___________________________________________ 79

    Personality as moderators of family risk _______________________________ 80

    Personality as mediators of family risk ________________________________ 83

CHAPTER FIVE______________________________________________________ 92

STUDY ONE ________________________________________________________ 92

Method _____________________________________________________________ 99

         Participants_________________________________________________ 99

         Measures __________________________________________________ 99

         Procedure _________________________________________________ 105

Results _____________________________________________________________ 105

    Data Screening__________________________________________________ 105

    Reliability and Validity Tests ______________________________________ 109

    Descriptive Information___________________________________________ 112

    Similarities and differences in reinforcement sensitivity across groups ______ 117

    Relative contribution of family risk and reinforcement sensitivity to

    dysfunctional eating and hazardous drinking __________________________ 120

    Reward and Punishment sensitivity as moderators of family risk and

    hazardous drinking and dysfunctional eating __________________________ 125

    Reward and punishment sensitivity as mediators of family risk factors and

    daughters’ dysfunctional eating and drinking __________________________ 130

Discussion __________________________________________________________ 133

    Reinforcement sensitivity and addictive behaviour______________________ 134

    Family factors and dysfunctional eating and drinking ___________________ 137

    Reward and punishment sensitivity as moderators of comorbidity and

    dysfunctional eating _____________________________________________ 140

    Reward and punishment sensitivity as mediators between mothers’ eating

    and family environment on daughters’ dysfunctional eating and drinking ___ 142

CHAPTER SIX _____________________________________________________ 146

STUDY TWO_______________________________________________________ 146

    Laboratory studies of reward sensitivity in hazardous drinkers and

    dysfunctional eating women _______________________________________ 147

    Laboratory studies of punishment sensitivity in hazardous drinkers and

    dysfunctional eating women _______________________________________ 149

    Behavioural tasks of RST _________________________________________ 153

         Q Task ___________________________________________________ 153

         Card    Arrangement     Reward     Responsiveness     Objective     Test

         (CARROT) _______________________________________________ 155

Method ____________________________________________________________ 157

         Participants _______________________________________________ 157

         Materials _________________________________________________ 158

                Tasks _______________________________________________ 158

                Questionnaires ________________________________________ 162

         Procedure _________________________________________________ 163

Results ____________________________________________________________ 163

    Descriptive information __________________________________________ 164

         Order effects on the Q Task and CARROT_______________________ 166

    Validation of the Q Task __________________________________________ 166

         Conditioning Phase _________________________________________ 166

         Test Phase ________________________________________________ 167

    Relationship between Q Task performance and punishment sensitivity ______ 168

    Validation of the CARROT ________________________________________ 170

    Relationship between CARROT performance and reward sensitivity _______ 170

    Relationship between Q Task performance and dysfunctional eating and

    hazardous drinking ______________________________________________ 171

    Relationship between CARROT score and dysfunctional eating and

    drinking _______________________________________________________ 172

Discussion __________________________________________________________ 172

    Validity of the Q Task and the CARROT _____________________________ 173

    Relationships between the Q Task and dysfunctional eating, hazardous

    drinking and comorbidity _________________________________________ 176

    Relationship between CARROT and dysfunctional eating, hazardous

    drinking and comorbidity _________________________________________ 178

CHAPTER SEVEN___________________________________________________ 180

General discussion ___________________________________________________ 180

REFERENCES ______________________________________________________ 189

APPENDIX A _______________________________________________________ 216

APPENDIX B _______________________________________________________ 219

APPENDIX C _______________________________________________________ 221

APPENDIX D _______________________________________________________ 222

APPENDIX E _______________________________________________________ 223

APPENDIX F _______________________________________________________ 226

APPENDIX G _______________________________________________________ 227

APPENDIX H _______________________________________________________ 232

                                 List of figures

Figure 1. Hypothesised placement of Gray’s personality traits of impulsivity and

    anxiety in relation to Eysenck’s personality traits of neuroticism and

    extraversion _____________________________________________________ 34

Figure 2. Standardised mean scores across groups of non-disordered,

    dysfunctional eating, hazardous, and comorbid women (error bars display ± 2

    SEM)__________________________________________________________ 119

Figure 3. Regression lines for relationship between maternal bulimia score and

    daughters’ bulimia as moderated by sensitivity to punishment (a 2-way

    interaction)._____________________________________________________ 129

Figure 4. Consequences to approaching or inhibiting “Q present” and “Q absent”

    letter strings. ____________________________________________________ 160

                                   List of tables

Table 1. Co-occurrence of dysfunctional eating and substance misuse in

     community samples________________________________________________ 26

Table 2. General behavioural expressions of high and low BIS reactivity

     supported by experimental studies ____________________________________ 40

Table 3. General behavioural expressions of high and low BAS reactivity

     supported by experimental studies ____________________________________ 42

Table 4. Impulsivity/reward sensitivity and anxiety in drug and alcohol misusing

     populations ______________________________________________________ 50

Table 5. Impulsivity and anxiety in women who binge-eat/purge, with and without

     co-occurring alcohol-use problems ____________________________________ 56

Table 6. Summary of studies testing moderation between family factors and

     personality traits on alcohol misuse and dysfunctional eating _______________ 82

Table 7. Summary of studies testing impulsivity and anxiety as mediators of

     family factors and alcohol misuse and dysfunctional eating ________________ 86

Table 8. Summary of means, standard deviations and Cronbach’s alpha

     coefficients of key measures ________________________________________ 111

Table 9. Sample characteristics on measures of alcohol misuse, dysfunctional

     eating, parental alcohol abuse, maternal eating, and family environment _____ 115

Table 10. Bivariate correlations between family risk factors, personality and

     dysfunctional eating and drinking____________________________________ 116

Table 11. Tests of main effects of personality and family factors in prediction of

     group membership (Non-disordered, Dysfunctional Eating only, Hazardous

     Drinking only, Comorbid)__________________________________________ 121

Table 12. Parameter estimates for multinomial logistic regression model relating

    group membership (Non-disordered, Dysfunctional Eating only, Hazardous

    Drinking only, Comorbid) to personality and family factors _______________ 124

Table 13. Interactions between sensitivity to reward and sensitivity to punishment

    with Maternal eatingand drinking on daughters’ eating and drinking ________ 128

Table 14. Tests of mediatory pathways between family factors and dysfunctioning

    eating and hazardous drinking via personality __________________________ 132

Table 15. Sample characteristics on measures of alcohol misuse, disordered eating

    and personality (N = 130) _________________________________________ 165

Table 16. Bivariate correlations between self-report reward and punishment

    sensitivity, Q Task and CARROT performance, dysfunctional eating and

    hazardous drinking _______________________________________________ 169

Table E.1.Obliquely rotated factor loadings of the modified maternal DT and

     Bulimia scale items_______________________________________________ 222


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