Cerith S. Waters Acceptance and Commitment Therapy - ORCA

171 Pages·2012·13.1 MB·English

Acceptance and Commitment Therapy:

Efficacy and Mechanisms of

Therapeutic Action

Cerith S. Waters

May 2012

Thesis submitted in partial fulfilment of the requirement for the degree of
Doctor of Clinical Psychology at Cardiff University and the
South Wales Doctoral Course in Clinical Psychology

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DEDICATION

I would like to dedicate this Thesis to my little ladies. To Lucy, for putting up with my absences
in recent months and for nurturing my girls. To Arianwen, for helping to bring some perspective
to my world and for making me smile and laugh each day—even the tough ones : ) And to
Gwendolyn, for keeping me company during the late evenings and for being the most
content and happy little baby, I cannot wait to watch you grow and develop!
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ACKNOWLEDGEMENTS

First and foremost, I would like to thank all of the participants who so generously gave up their
time to complete the questionnaires and interviews at a rather stressful point in their lives. I
would like to extend my gratitude to my supervisors, Dr Jane Boyd for her ideas, support and her
help in getting this research study ‘off the ground’, and Dr Neil Frude for his careful reading of
the manuscript and his reliability throughout all stages of this research. Appreciation is also due
to Dr Clare Wright for helping to manage the day-to-day running of this study, and the times
when the needs of this research conflicted with those of the Employee Wellbeing Service. A big
thank you is also due to the members of staff at the Employee Wellbeing Service, particularly
Julie, Shuit, Ruth, Linda and Sue for running the Acceptance and Commitment Therapy
workshops and for recruiting the participants.

As always, I would like to express my heartfelt gratitude to my grandparents, Lilian and Peter,
and my mother Diane, for their belief, love and encouragement. You can be assured that I am
leaving University for the last time—and that I will never have to write another Thesis again!
Also my siblings Rhianon, Sian and Tomas deserve a mention for being there, and for helping
me to ‘keep it real’. A huge thank you also goes to Debbie and Rob, I would never have written
up this research, or indeed been able to complete the other aspects of my clinical training had
you not been there to look after my girls, you are both very special and kind people!

Close friends from Cardiff and afar also deserve an accolade for helping me to relax and
experience anything other than clinical psychology training during the last three years. A high
five is suitably due to the Skills for Living Team (Liz [don’t leave me hanging : )], Andy, Chris,
Kerrie and Jess) for keeping me mindful and laughing. The young people I have worked with
should also be acknowledged for reminding me why I am doing this in the first place—it has
been a privilege : ) Last but not least, massive respect goes out to my fellow 2009 trainees
(Nomes, Suzie, Will, Hayley, James, Caroline, Lucy, Helen, Vicky, Helen M and Jess), you have
never failed to impress, encourage and inspire me. You have made the last three years a truly
wonderful experience and there will always be a special place in my heart for you!
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A POEM

The Guest House

This being human is a guest house.
Every morning a new arrival.

A joy, a depression, a meanness,
some momentary awareness comes
as an unexpected visitor.

Welcome and entertain them all!
Even if they're a crowd of sorrows,
who violently sweep your house
empty of its furniture,
still, treat each guest honourably.
He may be clearing you out
for some new delight.

The dark thought, the shame, the malice,
meet them at the door laughing,
and invite them in.

Be grateful for whoever comes,
because each has been sent
as a guide from beyond.

By Rumi

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ABSTRACT

The individual, organisational and societal impact of psychological distress among working
populations is well established. Recently, Acceptance and Commitment Therapy (ACT) has been
identified as a promising approach for improving the psychological wellbeing of distressed
employees. Nonetheless, few studies have examined the efficacy of ACT in the occupational
context and even fewer studies have conducted comprehensive tests of the mechanisms of
therapeutic action in ACT.

The current research examined the efficacy of a one day ACT intervention that was delivered to
NHS employees experiencing psychological distress. A key focus of this research was an
examination of the mechanisms of therapeutic action in ACT. In study one, a non-randomised
controlled design was used with 17 participants assigned to the ACT intervention and 18
participants assigned to a waiting list. A two-week and three-month follow-up period was used in
this study. Participants originally assigned to the waiting list went on to receive the intervention
after the three month follow-up and were again assessed at two-weeks and three-months post-
treatment. In study two, six of the participants were interviewed about their views on the aspects
of the ACT intervention that promoted psychological changes and their responses were analysed
thematically.

Compared to the control group, participants who received the intervention displayed statistically
significant reductions in the severity of psychological distress at two-weeks and three-months
post-treatment. Importantly, the majority of participants displayed clinically significant change at
both assessments. In line with ACT’s theoretical underpinnings, the intervention significantly
increased participants’ psychological flexibility and mindfulness skills and decreased cognitive
fusion. However, in a multiple-mediator statistical analysis, improvements in psychological
distress were only mediated by improvements in psychological flexibility. The themes generated
from the thematic analysis converge with the quantitative data—resembling closely the construct
of psychological flexibility. Limitations of the study and implications for future research are
discussed.

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CONTENTS

CHAPTER ONE – INTRODUCTION
1.1. Focus of the Thesis...................................................................................................... 1
1.2. Psychological Distress................................................................................................. 2
1.3. The Identification of the Literature for this Thesis...................................................... 2
1.3.1. The Inclusion and Exclusion Criteria................................................................. 3
1.4. Psychological Distress in the Workplace..................................................................... 4
1.5. Acceptance and Commitment Therapy (ACT): Theoretical Underpinnings.............. 6
1.5.1. The Evolution of the Behavioural Therapies.................................................... 6
1.5.2. Relational Frame Theory.................................................................................. 8
1.6. The ACT Model of Psychological Distress and Wellbeing........................................ 9
1.6.1. Cognitive Fusion and Experiential Avoidance................................................. 10
1.6.2. Theoretical Developments with ACT: The Focus on Psychological
11
Flexibility...........................................................................................................
1.6.3. ACT as a Psychological Intervention: Six Core Processes............................... 12
1.6.3.1. Acceptance........................................................................................ 12
1.6.3.2. Cognitive Defusion............................................................................ 12
1.6.3.3. Values................................................................................................ 14
1.6.3.4. Committed Action.............................................................................. 14
1.6.3.5. Self as Context................................................................................... 14
1.6.3.6. Being Present.................................................................................... 14
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1.6.4. Evidence for the Techniques that Target the Six Core Processes..................... 15
1.7. Intervention Studies that have Examined the Efficacy of ACT and Tested Potential
Mechanisms of Change................................................................................................ 16
1.7.1. Samples and Populations.................................................................................. 16
1.7.2. Methodological Characteristics of the Included Studies................................... 24
1.7.2.1. Design and Recruitment.................................................................... 24
1.7.2.2. Sample Size and Attrition.................................................................. 25
1.7.2.3. Intervention Delivery and Follow-up................................................ 26
1.7.3. Outcomes and Efficacy...................................................................................... 26
1.7.4. Mechanisms of Change in the ACT Intervention Studies.................................. 28
1.8. Chapter Summary........................................................................................................ 30
1.9. The Present Thesis....................................................................................................... 32

CHAPTER TWO – STUDY ONE

The Efficacy of the Acceptance and Commitment Therapy Intervention and the
Mechanisms of Therapeutic Action
2.1. Overview and Aims..................................................................................................... 33
2.2. Method......................................................................................................................... 35
2.2.1. Design................................................................................................................ 35
2.2.2. Rational for Using Quantitative Methodology................................................... 35
2.2.3. The Participants.................................................................................................. 36
2.2.3.1. Power Analysis.................................................................................. 36
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2.2.3.2. Recruitment....................................................................................... 36
2.2.3.3. Participant Characteristics............................................................... 37
2.2.4. Measures............................................................................................................ 38
2.2.4.1. Outcome Measure............................................................................. 39
2.2.4.2. Process Measures.............................................................................. 40
2.2.5. The Intervention................................................................................................. 43
2.2.6. Procedure........................................................................................................... 46
2.2.7. Ethical Considerations....................................................................................... 46
2.2.8. Data Analysis..................................................................................................... 47
2.2.8.2. Statistical Significance...................................................................... 48
2.2.1.2. Clinical Significance......................................................................... 48
2.2.1.3. Statistical Mediation......................................................................... 50

2.3. Results..........................................................................................................................
53
2.3.1. Assumptions for Parametric Statistics............................................................... 53
2.3.2. Sample and Group Comparability...................................................................... 53
2.3.3. Attrition.............................................................................................................. 54
2.3.4. Statistical Significance of Change..................................................................... 55
2.3.5. Clinical Significance of Change........................................................................ 56
2.3.6. Mechanisms of Therapeutic Action................................................................... 58
2.4. Discussion.................................................................................................................... 63

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CHAPTER THREE – STUDY TWO
Participants’ Experiences of the Impact of an Acceptance and Commitment Therapy
Intervention
3.1. Overview and Aims..................................................................................................... 66
3.2. Method......................................................................................................................... 67
3.2.1. Design.............................................................................................................. 67
3.2.2. Qualitative Research: Principles and Rationale............................................... 67
3.2.3. Thematic Analysis: Principles and Rationale.................................................. 68
3.2.4. Ensuring Quality in Qualitative Research........................................................ 69
3.2.5. The Researcher’s Perspective.......................................................................... 70
3.2.6. Ethical Approval, Consent and Confidentiality............................................... 71
3.2.7. Recruitment..................................................................................................... 71
3.2.8. Participant Portraits......................................................................................... 72
3.2.9. Interviews and Procedure................................................................................ 74
3.2.10. Data Analysis..................................................................................... 75
3.3. Results.......................................................................................................................... 76
3.3.1. Precipitating Factors........................................................................................ 76
3.3.1.1. Personal and Professional Stressors................................................ 77
3.3.1.2. Loss of Control.................................................................................. 79
3.3.2. Comparisons Between Well and Unwell Selves.............................................. 79
3.3.2.1. Self-Comparisons.............................................................................. 80
3.3.2.2. Other People’s Comparisons............................................................ 80
3.3.3. Components of Change.................................................................................... 81
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