Herbal medicine use in adults experiencing anxiety

215 Pages·2016·3.4 MB·English

Herbal medicine use in
adults experiencing anxiety:
Understanding a complex health behaviour

Erica Louise McIntyre
Bachelor of Health Science, Bachelor of Psychology (Honours)
School of Psychology, Charles Sturt University

A thesis submitted for the degree of Doctor of Philosophy (Psychology) at
Charles Sturt University in February 2016

Table of contents
Certificate of original authorship ............................................................................ viii
Acknowledgements .................................................................................................... ix
Statement of contributions to jointly authored works contained in this thesis and
published works by the author contained in this thesis ............................................. x
Work published by the author incorporated into the thesis...................................... x
Relevant work published by the author not forming part of the thesis .................. xi
List of abbreviations ................................................................................................. xii
Abstract .................................................................................................................... xiii
1. Herbal medicine use in adults who experience anxiety: Introduction to the
research ................................................................................................................ 1
1.1. Aims and scope of thesis ...................................................................................... 1
1.1.1. Research aim ..................................................................................... 1
1.1.2. Research objectives ........................................................................... 1
1.1.3. Research questions ............................................................................ 1
1.1.4. Significance and scope of thesis ......................................................... 2
1.1.5. Thesis structure ................................................................................. 2
1.2. Anxiety in the modern world: an overview ........................................................ 3
1.2.1. Epidemiology of anxiety in Australia ................................................. 4
1.2.2. Defining the experience of anxiety..................................................... 5
1.2.3. Core anxiety symptoms ..................................................................... 6
1.2.4. Conventional treatments for anxiety .................................................. 7
1.2.5. Pharmaceutical treatments for anxiety symptoms ............................... 8
1.2.6. Psychological treatments for anxiety symptoms ................................. 9
1.2.7. Complementary and alternative medicine (CAM) ............................ 11
1.3. An overview of herbal medicine ........................................................................ 11
1.3.1. A brief history of herbal medicine use ............................................. 12
1.3.2. Herbal medicine in contemporary Australia ..................................... 13
1.3.3. Prevalence of herbal medicine use in Australia ................................ 14
1.3.4. Herbal medicines for treating anxiety symptoms .............................. 15
1.3.5. Safety of herbal medicines used for anxiety symptoms .................... 16
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1.4. Herbal medicine use in adults experiencing anxiety: A public health issue ... 17
1.4.1. What is health behaviour? ................................................................ 18
1.4.2. Health literacy ................................................................................. 19
1.4.3. Health information seeking .............................................................. 20
1.4.4. Shared decision-making (SDM) ....................................................... 22
1.5. The use of theory in understanding herbal medicine use behaviour ............... 23
1.5.1. The importance of theory ................................................................. 23
1.5.2. Health behaviour theories explaining CAM use ............................... 24
1.5.3. Determining a suitable health behaviour theory................................ 25
1.6. The research design ........................................................................................... 26
1.6.1. The researchers position .................................................................. 27
1.6.2. Pragmatism ...................................................................................... 27
1.6.3. Sequential Exploratory Design ......................................................... 27
2. Prevalence and predictors of herbal medicine use in adults experiencing
anxiety: A critical review of the literature ........................................................ 30
2.1. Introduction ....................................................................................................... 30
2.2. Background ........................................................................................................ 30
2.3. Method ............................................................................................................... 32
2.3.1. Literature search strategy ................................................................. 32
2.4. Results ................................................................................................................ 36
2.4.1. Prevalence of Herbal Medicine Use in Adults with Anxiety ............. 36
2.4.2. Beliefs and Attitudes Towards Herbal Medicines ............................. 41
2.5. Discussion ........................................................................................................... 57
2.6. Conclusion .......................................................................................................... 59
3. Herbal medicine use in adults who experience anxiety: A qualitative
exploration ......................................................................................................... 61
3.1. Introduction ....................................................................................................... 61
3.2. Background ........................................................................................................ 61
3.3. Materials and Methods ...................................................................................... 63
3.3.1. Sample Strategy and Participants ..................................................... 63
3.3.2. The role of the researcher ................................................................. 64
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3.3.3. Data collection and analyses ............................................................ 64
3.4. Results ................................................................................................................ 65
3.4.1. Description of participants and their herbal medicine use ................. 65
3.4.2. Major themes ................................................................................... 67
3.5. Discussion ........................................................................................................... 74
3.6. Conclusion.......................................................................................................... 76
4. Herbal medicine use behaviour in Australian adults who experience anxiety:
A descriptive study ............................................................................................ 78
4.1. Introduction ....................................................................................................... 78
4.2. Background ........................................................................................................ 78
4.3. Methods .............................................................................................................. 80
4.3.1. Recruitment and participants............................................................ 80
4.3.2. Procedure ........................................................................................ 81
4.3.3. Measures ......................................................................................... 81
4.3.4. Statistical analysis ........................................................................... 82
4.4. Results ................................................................................................................ 83
4.4.1. Participant demographics ................................................................. 83
4.4.2. Scale reliabilities and mental health characteristics of participants ... 84
4.4.3. Anxiety and medicine use characteristics ......................................... 85
4.4.4. Practitioner use and herbal medicine prescribing ............................. 86
4.4.5. Herbal medicine use ........................................................................ 88
4.4.6. Information sources ......................................................................... 92
4.4.7. Disclosure of herbal medicine use .................................................... 92
4.4.8. Anxiety severity and herbal medicine use for anxiety symptoms ...... 96
4.5. Discussion ........................................................................................................... 97
4.6. Conclusions ...................................................................................................... 102
5. Predicting the intention to use herbal medicines for anxiety symptoms:
A model of health behaviour ........................................................................... 103
5.1. Introduction ..................................................................................................... 103
5.2. Background ...................................................................................................... 103
5.2.1. Theory of reasoned action and planned behaviour .......................... 103
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5.2.2. Anxiety .......................................................................................... 106
5.2.3. Hypotheses .................................................................................... 107
5.3. Method ............................................................................................................. 108
5.3.1. Recruitment and sample ................................................................. 108
5.3.2. Measures ....................................................................................... 108
5.3.3. Development of TPB items ............................................................ 108
5.3.4. Data analysis ................................................................................. 109
5.3.5. Data screening ............................................................................... 109
5.4. Results .............................................................................................................. 115
5.4.1. Exploratory factor analysis (EFA) .................................................. 115
5.4.2. Reliability ...................................................................................... 119
5.4.3. Structural equation modelling (SEM) ............................................. 119
5.5. Discussion and conclusion ............................................................................... 123
5.6. Chapter summary ............................................................................................ 125
6. General discussion and conclusion .................................................................. 126
6.1. Overview .......................................................................................................... 126
6.2. Primary findings .............................................................................................. 126
6.2.1. Prevalence of herbal medicine use in adults experiencing anxiety .. 126
6.2.2. Safe and effective use of herbal medicines: a public health issue .... 126
6.2.3. Beliefs and attitudes influencing herbal medicine use for anxiety
symptoms ...................................................................................... 132
6.2.4. Anxiety symptoms influence the decision to use herbal medicines . 133
6.3. Implications of findings ................................................................................... 136
6.3.1. Implications for people seeking treatment for anxiety symptoms.... 136
6.3.2. Implications for conventional health practitioners and herbal medicine
practitioners treating anxiety .......................................................... 137
6.3.3. Implications for policy makers ....................................................... 140
6.4. Significant contributions of the research ........................................................ 145
6.4.1. Health behaviour research .............................................................. 146
6.4.2. Health services research ................................................................. 147
6.4.3. Clinical research ............................................................................ 148
6.4.4. Public health research .................................................................... 149
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6.5. Limitations ....................................................................................................... 149
6.6. Conclusion........................................................................................................ 151
7. References ........................................................................................................ 153
Appendix A : Ethics approval for the qualitative study ........................................ 169
Appendix B : Advertisement for qualitative study ................................................ 171
Appendix C : Information sheet for quantitative study ........................................ 172
Appendix D : Interview guide for qualitative study .............................................. 174
Appendix E : Interview questions for qualitative study ........................................ 175
Appendix F : Survey invitations for quantitative study ........................................ 176
Appendix G : Ethics approval for the quantitative study ..................................... 177
Appendix H : Information page for online quantitative study .............................. 179
Appendix I : Questionnaire for the online quantitative study............................... 181
Appendix J : Theory of planned behaviour, hypothesised constructs and 36 items
included in questionnaire and recoded response scales ................................. 194
Appendix K : Communality values for items in final EFA model ........................ 198
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List of Tables
Table 1.1. Twelve month and lifetime weighted estimates for each anxiety disorder
from the National health and Wellbeing Survey 2007 .................................... 4
Table 2.1. Inclusion and exclusion criteria for literature review: aim one ................... 33
Table 2.2. Inclusion and exclusion criteria for literature review: aim two ................... 35
Table 2.3. Studies reporting the prevalence of herbal medicine use in adults with
anxiety disorders or anxiety symptoms ........................................................ 39
Table 2.4. Cross-sectional surveys on beliefs and attitudes as predictors of
positive attitude towards herbal medicine, and herbal medicine or
herbal practitioner use ................................................................................ 43
Table 2.5. Belief systems predicting attitudes towards, or use of CAM ........................ 49
Table 2.6. Treatment beliefs and attitudes predicting positive attitudes towards
CAM, intention to use CAM, or CAM use ................................................... 51
Table 2.7. Control and empowerment beliefs and attitudes predicting positive attitudes
towards, intention to use, or actual use of CAM .......................................... 55
Table 3.1. Major themes and subthemes reflecting beliefs and attitudes to herbal
medicines .................................................................................................... 68
Table 4.1. Participants’ demographics including: age, gender, state of residence,
and education level ..................................................................................... 84
Table 4.2. Scale reliabilities of the DASS-21 and STAI ................................................ 85
Table 4.3. Type of health practitioner seen and prescription of herbal medicines ........ 87
Table 4.4. Frequency of herbal medicines used to treat anxiety symptoms and who
prescribed each medicine ............................................................................ 89
Table 4.5. Percentage of users for each herbal medicine preparation.......................... 91
Table 4.6. Frequency of use of herbal medicine information sources ........................... 92
Table 4.7. Disclosure of herbal medicine use to doctor and other
health practitioners ..................................................................................... 94
Table 4.8. Anxiety disorder diagnosis and anxiety symptoms in previous 12 months
predicting herbal medicine use .................................................................... 97
Table 4.9. Logistic regression predicting likelihood of current herbal medicine
use for anxiety symptoms ............................................................................. 97
Table 5.1. Assessment of normality for items included in analysis ............................. 111
Table 5.2. Exploratory factor analysis final factor structure and loadings ................. 116
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Table 5.3. Descriptive statistics for the latent constructs in the hypothesised
path model, including Chronbach’s alpha ................................................. 119
Table 5.4. Summary of Goodness-of-fit Indices for the 4-factor
measurement model .................................................................................. 121
Table 5.5. AVE, CR and factor loadings for latent factors ......................................... 122
Table 5.6. Summary of Goodness-of-fit Indices for the path model predicting intention
to use herbal medicines for anxiety symptoms ........................................... 122
List of Figures
Figure 2.1. Flow diagram of studies included in aim one. ............................................ 34
Figure 2.2. Flow diagram of studies included in aim two ............................................. 35
Figure 5.1. Hypothesised path diagram for predicting the intention to use herbal
medicines for anxiety symptoms. ............................................................ 107
Figure 5.2. Four factor measurement model. ............................................................. 121
Figure 5.3. Path model predicting intention to use herbal medicines for anxiety
symptoms. .............................................................................................. 123
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Certificate of original authorship
I hereby declare that this submission is my own work and that, to the best of my
knowledge and belief, it contains no material previously published or written by another
person nor material which to a substantial extent has been accepted for the award of any
other degree or diploma at Charles Sturt University or any other educational institution,
except where due acknowledgment is made in the thesis.

Any contribution made to the research by colleagues with whom I have worked at
Charles Sturt University or elsewhere during my candidature is fully acknowledged. I
agree that this thesis be accessible for the purpose of study and research in accordance
with the normal conditions established by the Executive Director, Library Services or
nominee, for the care, loan and reproduction of theses.

Signature

Erica Louise McIntyre
18 February 2016