Understanding Hoarding Symptoms in Children with Comorbid ADHD By Fiona Lynch, BA(Hons)

198 Pages·2016·13.87 MB·English

Understanding Hoarding Symptoms in Children with Comorbid ADHD

By
Fiona Lynch, BA(Hons)
Submitted in partial fulfilment of the requirements for the degree of
Doctor of Psychology (Clinical)
Deakin University
February, 2016

Acknowledgements
First and foremost, I would like to thank my primary supervisor, Professor Jane McGillivray.
Thank you for allowing me the independence I needed to learn, and providing endless
support in both my writing and DPsych progress. Your understanding of the multiple
demands of the DPsych and life in general was an absolute blessing. I would particularly like
to thank my two associate supervisors, Dr Richard Moulding and Dr Linda Byrne. It was a
privilege to be able to learn from you both, and I’m very grateful forthe expertise, guidance,
and editing that you provided. I am incredibly grateful to the many participants who took the
time to complete this study and acknowledged the need to improve our understanding of this
area. Many thanks to my wonderful friends andfamily for your endless support over the
years and for providing normality in my weeks. Finally, to my incredible DPsych friends, I
have been so lucky to be supported by you every step of the way, and am excited to continue
our adventure together.
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Abstract
Children and adolescents with attention-deficit/hyperactivity disorder (ADHD) are vulnerable
to developing comorbid hoarding disorder with severe negative impacts. Despite this, the
comorbidity between hoarding disorder and ADHD in childhood is poorly understood. This
thesis is comprised of three studies that together aimed to explore the nature of hoarding
symptoms in children and adolescents with comorbid ADHD. A correlated liabilities model
was developed that implicated genetic, neurological, and executive functioning components
in the comorbidity between hoarding disorder and ADHD. The phenomenology of hoarding
symptoms in children with comorbid ADHD was then explored through in-depth interviews
with 10 parents of children with ADHD and comorbid clinically significant hoarding
symptoms. A core theme of emotional distress emerged in parent reports of the hoarding
profiles of children with comorbid ADHD, which appeared to be linked with parental
accommodating behaviours, urges to acquire items, and negative impacts on the wider family.
The potential role of executive functioning in hoarding symptoms was explored through a
pilot study with 37 children aged 8-17 years with ADHD and 26 typically developing
controls whose parents completed questionnaires designed to assess their child’s executive
functioning, hoarding symptoms, and ADHD symptoms. Results suggested that children with
ADHD and clinically significant hoarding symptoms may have poorer executive functioning
compared to both children with ADHD without clinically significant hoarding symptoms and
typically developing controls. Sixteen of the children with ADHD completed
neuropsychological assessments of executive functioning including sustained attention,
spatial working memory, planning and inhibition. Performance on these tasks hinted that
hoarding symptoms may be associated with poorer spatial working memory, long planning
times on simple tasks and short planning times on complex tasks. Combined, these results
have important clinical implications for the early detection of hoarding symptoms in children
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and adolescents with comorbid ADHD and for the provision of interventions to prevent the
severe symptom progression of hoarding disorder.
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Table of Contents
Thesis overview and structure................................................................................................1
Chapter One.............................................................................................................................4
Introduction..............................................................................................................................4
Understanding Hoarding Disorder.............................................................................................4
Epidemiology and Impact of Hoarding Disorder...........................................................5
The Course of Hoarding Disorder..................................................................................7
Cognitive Behavioural Model of Hoarding Disorder....................................................8
Current Treatment Approaches for Hoarding Disorder...............................................10
Overview of ADHD.................................................................................................................12
Comorbidity of ADHD and Hoarding Symptoms in Childhood.............................................13
Summary and Rationale...........................................................................................................14
Study One Aim............................................................................................................14
Study Two Aim............................................................................................................14
Study Three Aim..........................................................................................................15
References (Chapter One)........................................................................................................16
Chapter Two...........................................................................................................................24
Study One. Hoarding in Attention-Deficit/Hyperactivity Disorder: Understanding the
Comorbidity............................................................................................................................24
Abstract....................................................................................................................................24
Introduction..............................................................................................................................26
Overlap between ADHD and hoarding disorder......................................................................28
Aetiological mechanisms implicated in the ADHD-hoarding disorder link............................33
Genetic factors.............................................................................................................33
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Neurological factors.....................................................................................................34
The role of executive functions....................................................................................37
Review method........................................................................................................................38
Empirical evidence in hoarding disorder.................................................................................38
Working memory.........................................................................................................38
Planning.......................................................................................................................39
Inhibition......................................................................................................................41
Empirical evidence of shared executive functioning difficulties in ADHD............................42
Summary..................................................................................................................................44
Clinical implications................................................................................................................45
Suggestions for future research................................................................................................47
References (Chapter Two).......................................................................................................49
Chapter Three........................................................................................................................65
Study Two. Phenomenology of Hoarding in Children with Comorbid ADHD: The
Perception of Parents.............................................................................................................65
Abstract....................................................................................................................................67
Introduction..............................................................................................................................70
Method.....................................................................................................................................72
Participants...................................................................................................................72
Materials......................................................................................................................73
Demographics Questionnaire...........................................................................73
Children’s Saving Inventory............................................................................73
Semi-structured Interview................................................................................74
Procedure.....................................................................................................................75
Data Analysis...........................................................................................................................75
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Results......................................................................................................................................76
Theme one: Emotional distress....................................................................................77
Theme two: Parental avoidance and accommodating behaviours...............................77
Theme three: Family impacts of hoarding...................................................................79
Theme four: Excessive acquisition and saving............................................................81
Theme five: Executive functioning..............................................................................82
Theme six: Parental insight and intervention...............................................................83
Discussion................................................................................................................................85
Conclusions and Clinical Implications....................................................................................90
References (Chapter Three).....................................................................................................91
Chapter Four..........................................................................................................................97
Study Three. Executive Functioning and Hoarding in Children with Comorbid
Attention-Deficit/Hyperactivity Disorder............................................................................97
Abstract..................................................................................................................................100
Introduction............................................................................................................................101
Method...................................................................................................................................105
Participants.................................................................................................................105
Materials....................................................................................................................106
Demographics................................................................................................106
ADHD............................................................................................................106
Hoarding........................................................................................................106
Executive functioning questionnaire..............................................................107
Neuropsychological assessments...................................................................108
Procedure...................................................................................................................109
Results....................................................................................................................................110
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Statistical Analyses....................................................................................................110
Sample Characteristics...............................................................................................111
Parental Report Questionnaires..................................................................................112
Neuropsychological Assessments..............................................................................115
Discussion..............................................................................................................................119
References (Chapter Four).....................................................................................................126
Chapter Five.........................................................................................................................135
Discussion..............................................................................................................................135
Overview of Thesis Findings.................................................................................................135
Clinical Implications..............................................................................................................137
Limitations.............................................................................................................................141
Conclusion and Future Directions.........................................................................................142
References (Chapter Five).....................................................................................................145
Appendix A: Copy of Study One Publicationand License Agreement.................................150
Appendix B: DSM-5 DiagnosticCriteria for Hoarding Disorder..........................................160
Appendix C: Plain Language Statement Qualitative Study...................................................161
Appendix D: Ethics Approval Letter.....................................................................................164
Appendix E: Online Questionnaire........................................................................................165
Appendix F: Plain Language Statement for Online Questionnaire.......................................173
Appendix G: Plain Language Statement for Neuropsychological Assessment –Parent.......176
Appendix H: Plain Language Statement for Neuropsychological Assessment –Child........178

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