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Effectiveness of Hypnotherapy in
Anxiety Disorders: A Systematic
Review
By
Aile Trumm, BSc (Hons), MSc, C.Hyp.
A thesis submitted to the University of Birmingham for the degree of
MSc Health Research Methods
Institute of Applied Health Research
College of Medical and Dental Sciences
University of Birmingham
September 2018
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Word count: 9077
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TABLE OF CONTENTS
1. Acknowledgements and the Statement of Contributions …………….….....5
2. Abstract………………………………………………………………………..….5
3. Aim of The Review……………………………………………………………....6
4. Background……………………………………………………………………....8
4.1. Key Concepts……………………………………………………….…8
4.1.1. Definition of Anxiety Disorders………………………………….…8
4.1.2. Epidemiology, Prevalence and Burden of Anxiety Disorders.….9
4.1.3. Definition of Hypnotherapy………………………………………..11
4.1.4. Research in Hypnotherapy………………………………………..13
4.2. Rationale for the Systematic Review……………………………….16
5. Methods.......................................................................................................19
5.1. Search Strategy ............................................................................19
5.2. Study Selection and Inclusion/ Exclusion Criteria..........................20
5.3. Data Extraction Strategy ...............................................................22
6. Quality assessment strategy .......................................................................22
7. Methods of data analysis/synthesis…………………………………………...23
8. Results …………………………………………………………………………....23
8.1. Search Results………………………………………………………....25
8.2. Description and Findings of Included Studies………………………25
8.2.1. Results of Individual Studies……………………………………......25
8.3. Methodological Quality of Included Studies………………………...31
9. Discussion………………………………………………………………………...33
9.1. The Overall Summary of Findings……………………………….…..33
9.2. Review Limitations…………………………………………………......34
9.3. Implications for Clinical Practice and Future Research…………....34
10. Conclusion………………………………………………………………………36
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10. Reference list………………………………………………………………….37
11.List of Tables and Figures
Table 1: Inclusion/Exclusion Criteria………………………………………….....21
Figure 1. Study flow diagram……………………………………………………..24
Table 2. Characteristics of included studies…………………………………….30
Table 3. Summary of Cochrane Risk of Bias Tool for Randomised
Controlled Trials…………………………………………………………………….32
12. Appendices……………………………………………………………………..47
Appendix 1. Search Strategy……………………………………………...47
Appendix 2. Inclusion/ Exclusion Criteria Form………………………....49
Appendix 3. Data Extraction Form………………………………………..50
Appendix 4. Risk of Bias Assessment…………………………………....63
Appendix 5. Example Letter to Experts…………………………………...65
Appendix 6. Excluded Studies……………………………………………..66
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1. Acknowledgements and the Statement of Contributions
Dr. Clare Davenport- dissertation supervisor
Emma Besijn- second reviewer
Student 1854646 contributed to the design and implementation of the research,
to the analysis of the results and to the writing of the manuscript.
2. Abstract
A systematic review was conducted on the effectiveness of hypnotherapy on
anxiety disorders. Aim: The aim of the proposed project was to systematically
review the relevant evidence for the effectiveness of hypnotherapy interventions
used for treatment of anxiety disorders. Background: Anxiety disorders
represent one of the major groups of disorders seen in psychiatry and in
medicine generally, having a high prevalence and often an early onset. Anxiety
disorders appear to be continually increasing in prevalence and pose a
significant morbidity burden. The treatment may be sometimes expensive and
time-consuming. Medication is known to have unpleasant side-effects.
Hypnotherapy treatments have demonstrated efficacy for several conditions and
there has been increasing interest in providing hypnotherapy in healthcare
settings as there is more awareness among the general population of alternative
and complementary therapies. Hypnotherapy may potentially provide an
alternative to medication in the treatment of anxiety disorders, especially
regarding children and young adults. Method: A systematic review of
randomised and non-randomised experimental studies investigating the
effectiveness of hypnotherapy on anxiety disorders that were published from
January 2007 to April 2018 was conducted. The population included in the
review were children and adults with any anxiety disorder. Intervention was any
type of hypnotherapy delivered by trained or untrained individuals from any
background. The comparison conditions were: relaxation, cognitive behavioural
therapy, systematic desensitisation, active interventions such as CBT,
psychological therapy, placebo and waiting list. The main outcome was any
change in symptoms of anxiety measured by any validated scale or assessment.
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The secondary outcome was any other positive or adverse health effect. The
systematic review methods were followed, including a clearly stated set of
objectives with pre-defined eligibility criteria for studies, systematic searching of
the literature, duplicate screening, data extraction, quality assessment and a
systematic presentation of the findings. A second reviewer was involved in the
search and quality assessment stages. A protocol was written and submitted
prior to conducting the study. Results: The current systematic search
discovered 3 randomised controlled trials. All controlled trials used active groups
(placebo or other intervention), one study utilised inactive control (treatment as
usual). All of the included studies were published in hypnotherapy journals. The
mean sample size was 107 (range 32-226). In total, 320 participants were
included. Two of the included studies investigated the effectiveness of
hypnotherapy in the treatment of Post-Traumatic Stress Disorder (PTSD), one
study included participants with anxiety disorders and mixed anxiety depressive
disorders. Participants who had PTSD experienced diverse traumatic events:
combat exposure or being exposed to terrorist activity. The results of these
studies all reported significant difference in the measured outcomes favouring
hypnotherapy compared to a control group. The results overall were
inconclusive due to methodological quality of the studies, mostly due to
problems with randomisation and blinding. Conclusions: The current
systematic review concludes that the evidence regarding the effectiveness of
hypnotherapy in the treatment of anxiety disorders is insufficient, mainly due to
methodological quality and the volume of research from which to draw definitive
inferences. More high-quality research is needed to assess the effectiveness of
hypnotherapy in anxiety disorders.
3. Aim of the review
The aim of the proposed project was to systematically review the relevant
evidence for the effectiveness of hypnotherapy interventions used for treatment
of anxiety disorders. Systematic review methods (Higgins and Green, 2011)
were followed, including a clearly stated set of objectives with pre-defined
eligibility criteria for studies, systematic searching of the literature, duplicate
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screening, data extraction, quality assessment and a systematic presentation of
the findings. A protocol was written and submitted prior to conducting the study.
The PICOS framework has been used to develop literature search strategies.
The PICOS components are as follows: population: children and adults with any
anxiety disorder (clinical or subclinical), including mixed anxiety and depression.
Intervention: any type of hypnotherapy delivered by trained or untrained
individuals from any background. Comparison: relaxation, cognitive behavioural
therapy, systematic desensitisation, active interventions such as CBT,
psychological therapy, placebo, psychological therapy and waiting list.
Outcomes: Change in symptoms of anxiety (for example: any self-report
assessment of anxiety disorders; general measures of anxiety and severity of
anxiety symptoms like the Beck Anxiety Inventory (BAI), the Hospital Anxiety
and Depression Scale- Anxiety (HADS-A); but not limited to only these
measures). Secondary outcome: any other positive or adverse health effect.
Study Design: Randomised and non-randomised experimental studies.
The objectives of the review were:
-To summarise existing literature estimating the effectiveness of hypnotherapy
for anxiety and mixed anxiety and depression disorders.
-To investigate factors that might modify effectiveness (e.g. type of
hypnotherapy used, type of anxiety disorder).
-To identify gaps and weaknesses in the research.
-To explore the implications of these findings for patients and healthcare
providers.
-To explore the implications of findings for further research.
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4. Background
4.1. Key concepts
4.1.1. Definition of Anxiety Disorders
Anxiety disorders were recognised and distinguished from other mental health
disorders causing a negative effect (for example depression), as early as Biblical
times. They were even recognised by ancient Greek and Latin physicians and
philosophers. Treatments comparable with modern day cognitive psychology
were known to be utilised at the time (Croq, 2015). However, in the early years
A.D. anxiety disorders were not recognised as separate disorders and only
achieved differential classification status again in the late 19th century (Selek,
2011; Horwitz, 2013). Now, anxiety disorders are defined by The Diagnostic and
Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) as: “disorders that
share features of excessive fear, anxiety and related behavioural disturbances.”
(Diagnostic and Statistical Manual of Mental Disorders, 2013, p. 189). The
American Psychiatric Association (APA) defines anxiety disorders as: “differing
from normal feelings of nervousness or anxiousness and involve excessive fear
or anxiety” (American Psychiatric Association, 2017). Furthermore, there is an
additional note about the diagnosis of anxiety disorders which requires the fear
or anxiety to be out of proportion to the situation or age inappropriate and
hinders a person’s ability to function normally (American Psychiatric Association,
2018).
Classification of the types of anxiety disorder did not change significantly until
2013. DSM-V re-classified obsessive-compulsive (OCD) and post-traumatic
stress disorders (PTSD) separately from anxiety disorders, whilst still
maintaining emphasis on a close relationship between previous and current
classification, placing them close in the manual and drawing links between them
(Andrews, et al., 2010). At the same time, separation anxiety disorder and
selective mutism were included as anxiety disorder subheadings (Kupfer, 2015).
Therefore, anxiety disorders according to the new classification are as follows:
separation anxiety disorder, selective mutism, specific phobia, social anxiety
disorder (social phobia), panic disorder, panic attack specifier, agoraphobia,
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generalized anxiety disorder (GAD), substance/medication-induced anxiety
disorder, anxiety disorder due to another medical condition, other specified
anxiety disorder and unspecified anxiety disorder (DSM-V, 2013; p. 189).
Although PTSD has been removed from DSM-V as aforementioned, it is still an
anxiety disorder according to NHS and Anxiety UK (Leary, 2016). Therefore, the
following systematic review will consider both DSM-IV and DSM-V
classifications.
4.1.2. Epidemiology, prevalence and burden of Anxiety Disorders.
Anxiety disorders represent one of the major groups of disorders seen in
psychiatry and in medicine generally (Bandelow and Michaelis, 2015; Kupfer,
2015; Baxter et al., 2014; Haller et al., 2014; Baxter et al., 2013; Revicki et al.,
2012; Kessler et al., 2005). In several countries, anxiety disorders are more
prevalent than mood disorders (e.g. depression, bipolar disorder), substance
use disorders and impulse control disorders (Kessler et al., 2010 and
Demyttenaere et al., 2004). There are various estimates of current global
prevalence of anxiety disorders ranging from 7.3% (Baxter et al., 2013) up to
33.7% (Bandelow and Michaelis, 2015). The wide variation of prevalence may
be attributed to various factors, including methodological differences in data
collection (for example use of diagnostic criteria, methods of data collection,
language differences or standardization of prevalence rates to the census
population of each site instead of to an identical population), biological
differences across ethnic groups, psychosocial differences and traumatic
stressors (war, poverty, natural disasters) (Bandelow and Michaelis, 2015).
Anxiety disorders seem to continually increase in incidence and prevalence
(Wittchen, 2002; Ballenger et al., 2001; Kessler RC, Wittchen and Hoyer, 2001).
According to a World Health Organisation (WHO) report (2017), anxiety
disorders are the 6th largest contributors to non-fatal health loss and the 10th
largest contributors towards years lost to disability globally. Four out of every
100 people suffer from an anxiety disorder worldwide, but North American, North
African and Middle Eastern regions appear to have a
higher than average rate (about 8 in 100), while East Asia has the lowest rate (3
in 100) (Remes, et al., 2016). In the United States, anxiety disorders affect
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nearly 40 million American adults, ages 18 and older, which is around 18% of
the population, every year (Anxiety and Depression Association of America,
2018; Merikangas, et al., 2010; Clarke, 2013). The National Institute for Health
and Care Excellence (NICE) (2011) reports that in Europe 22% of patients in
primary care present with some anxiety disorder per year, GAD being most
prevalent (Clarke, 2013). Women appear to be almost twice as likely to be
affected than men, regardless of age and geographical location (Remes, et al.,
2016).
Anxiety disorders pose a significant morbidity burden (Lenze and Wetherell,
2011) as they may be associated with increased impairments in psychosocial
functioning in daily activities, work productivity, health-related quality of life (e.g.
fatigue, somatic diagnoses) and suicide attempts (Baxter, et al., 2014; Haller, et
al, 2014). A significant burden on patient functioning and well-being often leads
to increased health care utilization and high economic burden (Haller, et al.,
2014; Konnopka, et al., 2009). In 2010, the societal cost for anxiety disorders in
European Union was estimated at €74.4 billion (Olesen, et al., 2012). In UK the
cost has been estimated to be £14.19 billion by 2026, which will be an increase
of almost 40% compared to 2007 (McCrone, et al., 2008).
Anxiety disorders are among the most persistent mental health conditions
(Lenze and Wetherell, 2011). Patients with GAD are often sub-optimally treated,
which adds to the burden of this disorder (Revicky et al., 2012), causing
considerable impairment in psychosocial and work functioning, benzodiazepine
and primary health care use, worsening the course of a range of comorbid
mental health, pain and somatic disorders, further increasing costs (Haller, et al.,
2014).
The treatment course of anxiety disorders is generally the following: a doctor
may suggest trying an individual self-help course for a month or two, to assess
whether it is effective in helping the patient learn to cope with anxiety.
This usually involves working from a book or computer programme individually,
with only occasional contact with the doctor. Alternatively, a patient may prefer
to attend a group course where people with similar problems meet with a
therapist every week to learn ways to tackle the anxiety. If these initial
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treatments don't help, the patient is usually offered either a more intensive
psychological treatment or medication, or combination of both (NICE, 2014;
Simos and Hofmann, 2013). In addition, NICE (2011) recognises alternative
complementary therapies for the treatment of anxiety disorders, hypnotherapy
included, but discourages the use of hypnotherapy without utilising medication
first or at the same time.
4.1.3. Definition of Hypnotherapy.
Hypnotherapy has been known and documented under different names and
ways of conducting the therapy have also differed since ancient civilizations
(Fredette, et al., 2013). In 18th century Austria, hypnosis was known as “animal
magnetism” or “mesmerism”, named after Franz Anton Mesmer (Powell and
Forde, 1995). Mesmerism was concerned with magnets in the Universe having
effect on people and developing theories of “animal magnetism”. The word
hypnosis comes from the Ancient Greek after “Hypnos” who was the God of
sleep and was first coined in relation to treatment by the Scottish doctor James
Braid (1795 – 1860) who rejected the theories of animal magnetism and
concentrated fully on researching hypnotherapy. He is regarded by many as a
first genuine hypnotherapist (Powell and Forde, 1995). Sigmund Freud was also
known to be practicing hypnotherapy early in his career and has been quoted to
have been struck by the success of curing hysteria with hypnotherapy. Freud
believed that by finding a cause, the cure will follow. Freud soon replaced
hypnotherapy with “free association” and “transference” on to the therapist. He
maintained at first that his psychoanalytic techniques may be only used in
conjunction with hypnotherapy but later abandoned the use of hypnosis. There
are some speculations surrounding his decision, one of them being that he
struggled to look people in the eye and as result chose to sit behind patients
whilst they lay on the couch. Another possible explanation is that he thought that
patients were recalling their childhood fantasies instead of actual events (Powell
and Forde, 1995).
According to Clarke (2013), hypnotherapy is still not easily or consistently
defined. National Health Service UK defines hypnotherapy as: “a type of
complementary therapy that uses hypnosis, which is an altered state of
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consciousness” (NHS Choices, 2017) which seems to disregard or discourage
hypnotherapy as an alternative (standalone) treatment. APA defines
hypnotherapy as a “state of consciousness involving focused attention and
reduced peripheral awareness characterised by an enhanced capacity for
response to suggestion“ (American Psychiatric Association, 2018). Griffiths
(2017) argues that the latter definition is so vague that it could be applied to
anyone watching advertisements on TV.
The term “hypnosis” is used interchangeably for both hypnotic state and the
procedure used to induce the state (Hӓuser, 2016). Hypnosis usually involves
suggestions for relaxation, calmness, tranquillity and imagery experiences
(Lynn and Kirsch, 2006; Clarke, 2013), contrary to the stigma of mind control
or mental submission (Kirsch, 1994). The hypnotic state may be distinguished
from other states of consciousness, such as sleep, wakefulness, relaxation
and meditation, by utilising neuroimaging techniques which have
demonstrated the role of divisions in the anterior cingulate and prefrontal
cortices during the hypnotic state, as hypnosis has been proven to be an
alpha-wave state (Jensen et al., 2017; Peter, 2015).
It is further confusing that there are many different types of hypnotherapy. To
name a few, there are traditional hypnotherapy, hypnoanalysis, Ericksonian
hypnotherapy, cognitive-behavioural hypnotherapy, clinical hypnotherapy,
solution focused hypnotherapy and Lesserian curative hypnotherapy (Kraft and
Kraft, 2005; Bryant, et al., 2005; Lesser, 1989), Neuro-Linguistic Programming,
Past Life Regression, Time Line Therapy and many more (Hypnotherapy
Directory, 2018). It is noteworthy that these different types of hypnotherapy
function in a rather varied manner. For example, traditional hypnotherapy
provides symptom relief through direct suggestion when the patient is in a
hypnotic state. Traditional hypnotherapists would say something along the lines
of “When I count to ten, your pain will completely disappear” (Golden, et al.,
1987).
On the other hand, cognitive-behavioural hypnotherapy integrates cognitive-
behavioural approaches to hypnotherapy, for example: mindfulness, hypnotic
suggestibility, imagery, behavioural science, cognitive therapy, neuromuscular
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relaxation, attention training as well as CBT. Ericksonian hypnotherapy uses
indirect suggestion and storytelling to alter behaviour (The UK College of
Hypnosis & Hypnotherapy, 2018). Clinical hypnotherapy is delivered by a
qualified hypnotherapist with a healthcare background who is a licensed
professional. Patients are treated in hypnotherapy with various techniques from
other disciplines instead of with hypnotherapy itself (Hypnotherapy Directory,
2018). In Lesserian curative hypnotherapy, hypnotic susceptibility is not
paramount as in other therapies. The hypnotic state is utilised to locate, identify
and correct the cause of the problem, subsequently eliminating the symptoms
(Lesser, 2010; Lesser, 1985). In light of the differences between therapies, it is
necessary to point out which type of hypnotherapy has been utilised.
4.1.4. Research in Hypnotherapy.
There have been two eminent approaches to research in hypnotherapy
according to Jensen et al. (2017). The first of these is hypnosis research, where
the nature of hypnosis itself is researched. There have been significant research
gains made regarding the nature of hypnosis, due to the development of
cognitive neuroscience and the application of neuroimaging methods (Jensen, et
al., 2017; Oakley and Halligan, 2013). There is also evidence that hypnotic
suggestions arouse changes in respective brain regions (Jensen, et al., 2017).
Major electroencephalographic (EEG) findings appear to support the altered
state of consciousness view, validating participants’ subjective responses to
hypnosis (Griffiths and Preece, 1984; Melzack and Perry, 1975). Furthermore,
recording techniques such as biofeedback show that during the hypnotic state,
the parasympathetic nervous system is activated. Therefore, the breathing
slows down, the heart beats slower, the muscles in the body become relaxed
and the rapid eye movements (REMS) are observed (Powell and Forde, 1995).
Although the hypnotic state shares some similarities with sleep state, it has been
argued that it is not a sleep state, as the attention of the subject has been
concentrated and he or she is aware of the sounds (therapists’ voice) and
suggestions (Golden et al., 1987). Bass (1931) suggests that the hypnotic state
only shares superficial resemblance to sleep, after discovering that the patellar
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reflex (the knee-jerk reaction) of patients in hypnosis was the same as if they
were in the waking state, whereas during sleep there is no response.
To further confuse matters, there are other perceived obstacles surrounding
hypnotherapy research. Namely, that there are various misconceptions and
fears surrounding hypnotherapy, most likely stemming from the historical
background and misuse of hypnosis by those commonly referred as
“showmen and charlatans” (Abudarham, 1991). Not all people who call
themselves hypnotherapists are equally qualified in hypnotherapy training.
There are issues surrounding practice regulations. For example, in the United
Kingdom there are currently no laws to regulate the level of training and
experience required to practice hypnotherapy (Hypnotherapy Directory, 2018).
In the United States, most states exert little or no direct regulation over the
practice of hypnotherapy (Hypnotherapists Union, 2018). Therefore, it was
necessary to investigate whether the qualifications of therapists in this
systematic review were mentioned in the research papers included.
Hypnotherapy treatments have demonstrated efficacy for a number of conditions
(Jensen, et al., 2017). There is indication from the existing systematic reviews
that the strongest empirical support is for use of hypnosis treatments in pain
management (Abbott, et al., 2017), irritable bowel syndrome (Schaefert, et
al. 2014, Webb, et al., 2007), insomnia, several stress-related medical
conditions (Lever, 1988) and PTSD symptoms (Rotaru and Rusu, 2016). Limited
and sometimes inconclusive evidence from literature reviews suggests that
hypnotic treatments may also be effective for a wide variety of other problems
and conditions such as depression (Alladin and Alibhai, 2007) and anxiety
(Hammond, 2010; Coelho, Canter and Ernst, 2007; Jensen, et. al., 2017).
There is growing interest in providing hypnotherapy in healthcare settings,
including the provision of hypnotherapy training to healthcare workers in the UK
(Abudarham, 1991) as hypnotherapy may also be relatively quick and
inexpensive, compared to more expensive and time consuming Cognitive
Behavioural Therapy (CBT) (Huston, 2010; Miller, Fletcher and Kabat, 1995). In
fact, Huston (2010) conducted a retrospective pre-post intervention looking into
the effectiveness of hypnotherapy in treating GAD, comparing hypnotherapy
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with CBT. No statistical difference between these two treatment arms was
found, therefore suggesting hypnotherapy was equally effective. Roy-Byrne
(2015) mentioned that psychiatrists struggle to offer the instantaneous relief
that is expected of them from anxious patients. On the other hand, the
sensation of a hypnotic state may provide a feeling of relaxation rather
quickly.
Hypnotherapy may potentially also be a valuable alternative to medication as it
has no side effects, whereas there are known problems and side effects
associated with some prescribed anxiety medications. Patients have reported
feeling dazed and unfocused, even when prescribed low doses. People who are
prescribed medication often experience medication hangovers as some of the
tranquillisers are highly addictive. Taking commonly prescribed anxiety
medication (benzodiazepines, beta blockers, SSRI antidepressants, Buspirone)
may disrupt work, school and everyday functioning for the patient due to side
effects and may cause problems later due to withdrawal (Smith, Robinson and
Segal, 2017).
NICE’s (2011) decision to include hypnotherapy as a complementary
intervention for the treatment of anxiety disorders was based on one paper by
Zhao et al. (2005). In the aforementioned paper, benzodiazepine treatment was
compared to application of hypnotherapy and no significant difference was
found, possibly suggesting an alternative to the medication (Zhao et al., 2005).
There remains controversy over NICE’S decision (Leary, 2016). On the contrary,
Nisith et al. (1999) argue in their trial that hypnotherapy may be considered as a
possible alternative to medication when comparing hypnotherapy to alprazolam
prescription.
Despite concerns about effectiveness and regulation, hypnotherapy is becoming
increasingly recognised as a potential method for reducing feelings of anxiety
(Robertson 2010) as in the past decade, there has been a vast increase in
research interest regarding anxiety disorders due to the recognition of the
prevalence, implications and morbidity burden of the illness (Remes, et al.,
2016). Furthermore, there is more evidence and interest in the effectiveness of
hypnotherapy (Jensen et al., 2017).
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4.2. Rationale for the systematic review
Hypnotherapy research for anxiety and depressive disorders has enjoyed
considerable growth until the early 1990’s but has since seen a decline (Jensen
et al., 2017). Various possible explanations are offered for this trend. The
change may be due to the loss of many influential prolific researchers who have
retired. These senior academics, linked to their institutions, attracted funding
and institutional support which many believe has not been equalled (Jensen et
al., 2017). Following the loss of leading research centres in hypnotherapy,
research has become an individual pursuit. On the other hand, Jensen et al.,
(2017) also claims that after the hiatus, the past decade has seen many
advances in hypnotherapy research.
An additional challenge may be that hypnotherapy research continues to be
labelled “unscientific” in the broader research community (Polito, Barinier and
Cox, 2016; Raz, 2011).
However, there is some indication that the misconceptions about hypnosis may
be softening due to research progress. For example, the National Institutes of
Health in the United States of America has recognised hypnosis as a topic of
interest and has begun to fund large-scale studies evaluating the efficacy and
mechanisms of hypnosis treatments (Jensen, et al., 2017).
Furthermore, the scoping search uncovered a vast amount of research
regarding the effectiveness of hypnotherapy in pain management and the
treatment of IBS (Abbott et al., 2017; Jensen et al., 2017; Schaefert et al. 2014,
Webb, et al., 2007). There were numerous case reports and case studies
regarding anxiety disorders (GAD, phobias, PTSD), many reporting significant
symptom reduction due to hypnotherapy (Lupu and Lupu, 2017; Alladin, 2016;
Golden, 2012; Somer, 1995; Miller, 1986).
There is only one previous systematic review known to the author about the
efficacy of hypnotherapy in anxiety that includes randomised controlled trials
(RCTs). A systematic review published in 2007 by Coelho, Canter and Ernst
identified 14 RCTs which explored the efficacy of hypnosis for the treatment of
any type of anxiety. The different anxiety types included in the systematic review
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were the following: test anxiety (3 studies), dental anxiety or dental phobia (3
studies), phobic disorders including public speaking phobia (2 studies), PTSD-
related anxiety or PTSD (2 studies), anxiety neurosis (1 study) and unspecified
anxiety (3 studies). The main comparators were: waiting list, routine care, group
relaxation, discussion/contact and meditational relaxation. There were 657
participants overall, mean study size was n=47 (range n=13- n=112). Three
studies utilised university students. Participants were also recruited from trauma
survivors’ meetings and PTSD patients’ meetings. The quality of included
studies was low overall. Nine obtained a Jadad score of 1 (maximum score is 5)
because of the failure to describe their randomisation process, failure to mention
blinding and failure to provide a sufficient description of attrition. Four included
studies obtained Jadad score of 2 due to the same problems and only one study
obtained a Jadad score of 3. The main issue was the failure to describe the
randomisation procedure. There was no meta-analysis due to low
methodological homogeneity. The systematic review itself was assessed for
methodological quality utilising AMSTAR-2 (Shea et al., 2017). AMSTAR-2 is a
critical appraisal tool for systematic reviews that include both randomised and
non-randomised studies of healthcare interventions and is regarded to be a
popular and rather comprehensive tool (Shea et al., 2017).
The rating of the overall confidence in the results of the review was considered
high as there was one weakness such as not searching for grey literature. The
systematic review provides an accurate and comprehensive summary of the
results of the available studies that address the question of interest. All the other
domains were included.
Six electronic databases were searched (Coelho, Canter and Ernst, 2007 from
inception until February 2007. The search yielded 657 articles, 10 of which met
the inclusion/exclusion criteria and a further 4 were identified from reference
lists. Three RCTs of hypnosis for the treatment of either GAD or unspecified
anxiety were identified, the outcome measures utilised were the Willoughby
questionnaire and psychiatric interview utilising Hamilton Scale. Two trials
suggested that hypnosis is no more effective than meditation or no treatment.
One trial found hypnosis to be superior to both music relaxation and no
18
treatment. Two RCTs were identified for the treatment of trauma-related anxiety,
both having no significant difference. The outcome measures were STAI
(current state anxiety, pervasive trait anxiety) scales, SCL-90 (the Posttraumatic
Stress Disorder subscale), STAngerl and Impact of Events (IES) scales. Six
RCTs were found in relation to phobic anxiety, two of them treating
performance-related social phobia. A significant difference in favour of
hypnotherapy was found in relation to treating phobic anxiety. The outcome
measure was the mean of patient, therapist and independent assessor rating on
5-point scale for main phobia. Two studies investigating the treatment of
test/examination anxiety also found significant difference in favour of
hypnotherapy. Dental phobia and mixed phobic disorders were not significant.
Overall, the results were found to be inconclusive, mainly due to methodological
limitations of the included RCTs. No significant differences between hypnosis
and control conditions were found. It was claimed that some limited, yet
consistent evidence was found that hypnosis may be of benefit in alleviating
performance-related anxiety and test anxiety. The authors' conclusion was
supported by the evidence provided, but it was based on trials with small
samples and of low methodological quality. The systematic review did not
include children, who are known to benefit from hypnotherapy (Kuttner, 2009;
Hawkins and Polemikos, 2002; Huynh, et.al, 2008; Anbar, 2001).
The systematic review by Coelho, Canter and Ernst (2007) investigated adjunctive
therapy to hypnotherapy, without mentioning the type of hypnotherapy utilised.
The author of the current review has identified a lack of systematic reviews
investigating hypnotherapy as a standalone treatment when conducting scoping
searches. As different types of hypnotherapy operate slightly differently,
psychological treatments (such as CBT) in conjunction with hypnotherapy will be
inappropriate with some types of hypnotherapy, such as Lesserian Curative
Hypnotherapy which is a standalone treatment (Lesser, 2010; Lesser, 1989,
Lesser, 1985).
As it has been a decade since the last known systematic review and in light of
claimed advances in hypnotherapy research (Jensen et al., 2017), it was found
to be beneficial to conduct an update as it might be beneficial to explore
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advances in anxiety treatment with hypnotherapy, especially including children,
as anxiety disorders are quite prevalent in the population and often rather
complex to treat.
5. Methods
5.1. Search strategy
A database of published and unpublished literature has been assembled from
systematic searches of electronic sources, hand searching and consultation with
experts in the field. The search has been conducted in accordance with the
guidelines set out by Preferred Reporting Items for Systematic Reviews and
Meta-Analyses (PRISMA).
Electronic databases: The following electronic databases were searched from
January 2007 to April 2018, not restricted by language: AMED (Allied and
complementary medicine), EMBASE, CINAHL (Nursing and allied health),
MEDLINE (General medical), Cochrane Library, PsycINFO (Psychiatry,
psychology and social sciences), Open Grey, Web of Knowledge (Social
Sciences, Psychology and Humanities).
Other sources: The following sources were searched from January 2007 to
April 2018: IJCEH (The International Journal of Clinical and Experimental
Hypnosis), AJCH (American Journal of Clinical Hypnosis) and Contemporary
Hypnosis Journal (CHJ) have been searched for relevant published literature.
Information on studies in progress, unpublished research or research reported in
the grey literature was sought by searching a range of relevant databases
including the National Research Register and Current Controlled Clinical trials.
Bibliographies of relevant systematic reviews and primary studies have been
examined. (Please see Appendix 1 for search strategy). The search terms
remained relatively broad, as rather narrow search strategies did not seem to
provide an effective number of articles. Medical Subject Headings (MESH) and
text words were utilised (Appendix 3). RefWorks software package had been
used to manage references. There have been no language restrictions imposed.
20
5.2. Study Selection and inclusion/ exclusion criteria
The PICOS framework has been used to develop literature search strategies.
The PICOS components are the following:
P – patient, problem or population: Children and adults with any anxiety disorder
(subclinical included), including mixed anxiety and depression
I – intervention: Any type of hypnotherapy (cognitive, Ericksonian, solution
focused hypnotherapy, suggestion hypnotherapy, self-hypnosis)
Hypnotherapy delivered by trained or untrained individuals from any
background.
C-comparison: Relaxation, cognitive behavioural therapy, systematic
desensitisation, active interventions such as CBT, psychological therapy,
placebo, psychological therapy and waiting list.
O-outcomes: Change in symptoms of anxiety (for example: any self-report
assessment of anxiety disorders; general measures of anxiety and severity of
anxiety symptoms like Beck Anxiety Inventory (BAI), Hospital Anxiety and
Depression Scale- Anxiety (HADS-A); but not limited to only these measures).
Secondary outcome: any other positive or adverse health effect.
S- study Design: Randomised and non-randomised experimental studies.
The citations identified by the search strategy have been assessed for inclusion
in two stages by two reviewers. Firstly, all relevant titles and abstracts identified
via electronic searching have been screened by two independent reviewers, to
identify potentially relevant studies for inclusion in the review. Secondly, full text
copies of potentially relevant studies have been obtained and assessed by two
independent reviewers utilising the criteria outlined in Table 1. Any
disagreements between reviewers have been resolved by discussion at each
stage. Findings have been presented in the Preferred Reporting Items for
Systematic Reviews and Meta-Analyses (PRISMA) flow chart in the results
section (Figure 1).
21
Table 1: Inclusion/Exclusion Criteria
Inclusion
Exclusion
Justification
Population
Children and adults with
any anxiety disorder
according to DSM-IV,
DSM-V or by specialist
(subclinical included),
including mixed anxiety
and depression
Depression alone
In adults, anxiety may be
diagnosed with depression.
These diagnoses will not be
excluded as long as there are
outcomes specific to anxiety
measured.
Intervention
• Any type of hypnotherapy
(cognitive, Ericksonian,
solution focused
hypnotherapy,
• suggestion hypnotherapy,
self-hypnosis, etc).
Hypnotherapy to be
delivered by trained or
untrained individuals from
any background
Hypnotherapy combined
with other interventions
(e.g. psychological
interventions) not
including medication.
Not restricting the intervention
delivered only by
hypnotherapists; hypnotherapy
to be delivered by trained or
untrained individuals from any
background, as later on the
heterogeneity regards
hypnotherapists/self-
hypnosis/other specialists may
be explored.
Comparators
Medication, relaxation,
cognitive behavioural
therapy, systematic
desensitisation, CBT,
psychological therapy,
placebo, psychological
therapy and waiting list.
Hypnotherapy combined
with another treatment
(as for the intervention).
Limiting comparators does not
reflect current practice and
would not assist with trying to
determine the potential role of
hypnotherapy.
Outcomes
Primary outcome:
Change in symptoms of
anxiety. Secondary
outcome: any other
positive or adverse health
effect.
Measures such as
societal cost (e.g. time
off work, NHS costs
such as appointments
used).
The effects of hypnotherapy
are potentially wide ranging.
Excluding any form of health
outcome would be detrimental
to the main aims of the review.
Setting
Any setting
No exclusions
All settings to be considered.
Study design
Randomised and non-
randomised experimental
studies.
All other study designs.
The review is concerned with
effectiveness. Other aspects of
the intervention are of interest
but probably beyond the scope
of this review. Experimental
studies that are non-
randomised will be included
but these would need to be
considered as a separate
subgroup for analysis.
22
5.4. Data extraction strategy
Study details have been extracted by an initial reviewer using a standardised
data extraction form (Appendix 3) adapted from Cochrane Handbook (Higgins
and Green, 2011; Cochrane Collaboration Glossary, 2010). Data relating to
study design, findings and quality have been extracted by one reviewer and
independently checked for accuracy by a second reviewer.
6. Quality assessment strategy
The methodological quality of each randomised study included has been
assessed using a Cochrane risk of Bias Tool (Higgins and Green, 2011) as it is
regarded to be standard important approach in assessing risk of bias in
randomised clinical trials. Although the Cochrane Risk of Bias Tool is considered
an important step forward, it is worth noting that there are criticisms regarding
how it deals with risk of bias associated with funding, conflicts of interest and
modest inter-rater agreement (Jørgensen, 2016).
To evaluate the non-randomised controlled trials, ROBINS-I (Risk of Bias In
Non-randomised Studies - of Interventions), a tool for evaluating risk of bias has
been utilised. It is deemed particularly useful to those including non-randomised
studies in systematic reviews, as it estimates the comparative effectiveness of
non-randomised interventions, and is known to be accessible, easy to use,
structured and comprehensive (Sterne, et al., 2016).
The quality of individual studies has been assessed by one reviewer and a
selection has been independently checked for agreement by a second reviewer
to improve the rigour of the research. Disagreements have been resolved
through consensus; there has been no need for a third reviewer to be consulted.
All results have been tabulated in Table 2.
23
7. Methods of data analysis/synthesis
The results of the data extraction and quality assessment for each study have
been presented in structured tables and as a narrative summary. The possible
effects of study quality and factors that might alter direction and size of effect on
the effectiveness data and review findings have been discussed. When looking
at the effect of hypnotherapy on anxiety, there have been several different
outcome measures expected that included studies might have used. Therefore,
consideration has been given to whether there might be a need to use
standardised mean difference as a summary measure for meta-analysis.
The consideration for statistical quantitative analysis was given in terms of
heterogeneity (meta-regressions, funnel or forest plots, subgroup analyses),
meta-analysis, but due to the amount and quality of included research, it was
deemed inappropriate. Therefore, narrative tables and summaries have been
presented.
8. Results
8.1. Search Results
A total of 1544 records were identified through database, hand searching,
reference checking and contact with authors (Figure 1). After removing
duplicates, 1443 titles and abstracts were screened by two independent
researchers for inclusion/exclusion criteria (Appendix 2). Six full texts were
assessed for eligibility, three (Hudson, 2010; Daitch, 2018; Alladin, 2016) were
excluded due to not utilising the research design necessary for this systematic
review (Appendix 6). Therefore, three papers were included in the final review
(Table 2).
24
Figure 1. Study flow diagram
8.2. Description and Findings of Included Studies
AMERICAN
JOURNAL OF
CLINICAL
HYPNOSIS
N=397
AMED
N=16
COCHRANE
N=9
OPEN GREY
N=8
CINAHL
N=154
EMBASE, Medline
PsychInfo N=661
Reference checking and
contact with experts N=13
N=3 excluded : all due to not having the
randomised or non-randomised experimental
study design.
IJCEH
N=286
N= 1443 titles and abstracts screened
N=101 duplicates removed
N= 6 full text articles assessed for eligibility
N= 1438 records excluded (due to study
design, not standalone intervention, multiple
exclusions)
N=3 Included
1544 records identified through database searches
25
8.2.1. Results of Individual Studies
The Chiu et al., (2018) study was an RCT on the clinical use of hypnotherapy on
anxiety disorders and mixed anxiety and depressive disorders in Hong Kong’s
Chinese population. The comparator was treatment with conventional
psychiatric treatment (anxiolytic or antidepressant medication). 62 patients were
recruited from the Hypnotherapy Clinic of Kowloon Hospital, 57 of them
completed the study. There was no information on attrition, or about Intention to
Treat (ITT) analysis. The study ran from 2009 to 2012. The duration for
participants was 8 weeks, participants had 5 to 7 sessions depending on their
clinical conditions, each session lasted from 45 to 75 minutes. The qualifications
of the person who conducted hypnotherapy were not mentioned. There was no
mention about the type of hypnotherapy, but the authors mentioned that self-
hypnosis was encouraged. They did not describe how many participants utilised
it and to what extent. It appears that participants had different treatment as part
of the same intervention group which raises the problem as patients who had
more acute diagnosis were possibly given longer treatment. Recruited patients
were given information about the aim, method and timetable of the study,
possibly introducing bias by not blinding patients and staff. The baseline
characteristics were statistically tested, and no significance was reported, which
is highly discouraged by the CONSORT statement (Boer, et al., 2015). By
looking at their baseline table, there were differences between the balance of
male and female participants (hypnotherapy group had more females), mean
age and the duration of illness. The confounders were not included when
performing statistical testing. Participants were assessed using the following
clinical scales: Clinical Global Impression Scale (CGI), the Hamilton Depression
Scale (HDS), The Hamilton Anxiety Scale (HAS), The Hamilton Depression
Scale (HDS) and The Beck Anxiety Inventory (BAI). The study discovered that
the scores in the hypnotherapy condition were remarkably lower across all
scales, suggesting significant improvement of patients’ clinical condition,
compared to no significant improvement in the control group of conventional
treatment of anxiolytic or antidepressant medication. There was an indication
that the conventional treatment did not make any difference in the severity of
illness in 8 weeks.
26
A quasi-experimental, single blind RCT by Lesmana et al., (2009) assessed the
effectiveness of a spiritual-hypnosis assisted therapy for treatment of PTSD in
Bali Hindu children aged 6-12 after a terrorist bombing in Kuta. The study lasted
for 2 years from recruitment to follow-up. Time points reported in the study were
before treatment (2002) and after treatment (2004). There were 226 participants,
48 in the treatment group and 178 in the control group. Only the sex and age of
participants was provided in the baseline characteristics table. There were more
boys in the treatment group (52.1%) and more girls in the control group (53.9%).
No information regarding co-morbidities, socio-economic status was provided
which may have been potential confounders. The hypnotherapy sessions were
delivered in two subgroups, in groups of 23 and 25 children together, for the
convenience of the researchers. The entire group session of hypnosis lasted 30
minutes. It was the only study where the type and process of hypnotherapy was
fully described. The qualifications of the person who conducted hypnotherapy
were not mentioned. The improvement was measured with the questionnaires
which were administered to both treatment and control groups at the same time
points, before and after the hypnotherapy treatment. The questionnaire was
designed by the researchers and was based on the DSM-IV self-report
assessment of PTSD. Six psychiatry residents explained the symptoms of PTSD
and the questions in the questionnaire to the children whilst administering the
questionnaire. The outcomes were the following: improvement of PTSD
symptoms, the amount of PTSD symptoms and the triggers of PTSD symptoms.
The study claimed that of the children who received a single group session of
spiritual hypnotherapy, 77.1% showed improvement in PTSD symptoms
compared to 24.2 % in the control group who received no therapy. Multivariate
analysis was run on the symptom score differences between questionnaire
administered pre and post-treatment, the result being statistically significant with
t (224) =2.42, p<.05, two tails. The results indicated a statistically significant
difference favouring the hypnotherapy treatment in symptoms of re-experience,
hyperarousal and avoidance. A MANCOVA was performed, using age as
covariate. Wilks’ Lambda (3.222) = .94, p<.005 showing statistically significant
difference in all three individual symptom scores with hypnotherapy group
showing larger levels of symptom reduction. There was a mention of permission
requested from parents and teachers but no mention of the ethical
27
considerations in relation to providing no intervention to the control group. The
study reported a limitation of not comparing spiritual-hypnosis assisted therapy
with CBT, traditional hypnosis or any other intervention. The researchers justify
their choice of designing the research as in their opinion it supports the main
focus of bringing relief to the children.
Abramowitz et al., (2008) conducted an RCT to evaluate the benefits of
hypnotherapy compared to Zolpidem treatment. Of 32 male combat veterans
diagnosed with chronic PTSD, 17 were assigned to a hypnotherapy condition
and 16 to a Zolpidem condition. One person dropped out in the Zolpidem
condition, due to experiencing drowsiness. No ITT was mentioned when
performing statistical analysis. Patients were assigned to hypnotherapy
condition after evaluating hypnotisability with the Stanford Hypnotic
Susceptibility Scale (Weitzenhoffer and Hilgard, 1962) and only patients with
mid-range scores were included. The rationale was that the researchers’ claim
that, from their previous clinical experience, moderately hypnotisable patients
were best suitable for treatment. Hypnotherapy was administered by a specialist
in psychiatry who was regarded as experienced in hypnotherapy; no formal
hypnotherapy training was mentioned. Hypnotherapy was administered in two
1.5-hour sessions per week, for two weeks. There was no mention about the
type of hypnotherapy administered. Participants completed a daily morning
questionnaire about their quality of sleep during and a month after treatment.
There was a statistically significant main effect reported in the hypnotherapy
group, compared to the Zolpidem group, p=.034. There was also significant
main effect of the assessment time, p<.0005. Post hoc tests indicated that PTSD
symptoms reduced from a mean of 36.7 (SD = 9.4) to 31.7 (SD = 9.8) in
hypnotherapy group pre- and post-treatment. The effect was preserved at a
follow up a month after, with mean score being 31.5 (SD = 9.9). Also, PTSD
symptoms, stress reactions and sleep disturbances were lower in the
hypnotherapy group. There was a statistically significant interaction between the
treatment type (hypnotherapy and Zolpidem groups) and the different
assessments (pre-, post-treatment and 1 month follow up) with p<.0005. There
was a positive effect of hypnotherapy reported across all outcome measures in
this study, which were stress reactions, depression, sleep variables (total sleep
28
time, the quality of sleep, number of awakenings) and morning effects (ability to
concentrate and morning sleepiness). Researchers reported some limitations,
such as small sample size and choosing patients based on hypnotisability due to
researchers’ own experience.
All included studies were randomised controlled trials (Table 2). All controlled
trials used active groups (placebo or other intervention) and one study utilised
an inactive control (treatment as usual). All of the included studies were
published in hypnotherapy journals. Two were found from the IJCEH and one
from the AJCH. Both journals specialise in clinical or experimental hypnosis. The
mean sample size was 107 (range 32-226). In total, 320 participants were
included.
Two of the included studies investigated the effectiveness of hypnotherapy in
the treatment of PTSD, one study included participants with anxiety disorders
and mixed anxiety depressive disorders. All studies confirmed the diagnosis of
participants. The diagnosis was confirmed using clinician assessed diagnostic
criteria and through structured interviews. Participants who had PTSD
experienced diverse traumatic events: combat exposure or being exposed to
terrorist activity. The type of hypnotherapy utilised was mentioned only in one
paper by Lesman et al., (2011). One study mentioned the hypnotherapy
qualifications and/or experience of the hypnotherapist (Abramowitz, et al., 2008).
The results of these trials all report promising statistically significant differences
between treatment and control groups.
In order to conduct a meta-analysis, trials are expected to be homogenous:
using similar population, similar conditions, similar treatments, control groups
and at least one identical outcome (Cheung and Vijayakumar, 2016). As studies
were rather heterogeneous in terms of hypnotherapy used, different populations
(one study included only children, another included only male combat veterans
and the third one mixed male and female psychiatric patients) and the outcomes
were different, therefore the author sought to provide the understanding of the
evidence for each modality narratively.
29
Table 2. Characteristics of included studies
Study
n
%drop-
out or
Missing
Data
Participant
Characteristics
and Gender
Type of
Hypnotherapy
Duration of
Intervention
Comparison
and Duration
(where
applicable)
Hypnotherapy
Qualifications
of Person
Conducting
Hypnotherapy
Outcomes
Results
Chiu, et al.,
(2018)
62
8.1%
Chinese psychiatric
patients with anxiety
and depressive
symptoms, 68 %
Female
No mention but
self-hypnosis
had been added
to hypnosis.
5 to 7
sessions, 45-
75 minutes
per session, 8
weeks.
Conventional
psychiatric
treatment
(medication) 8
weeks
No mention
Severity index
of CGI, HAS,
HDS, BDI, BAI
Statistically significant
improvement in all outcomes
favouring hypnotherapy. Chi
square or t-tests CGI results:
2.42 (conventional treatment) vs
1.13 hypnotherapy, p<.001
Lesmana, et
al., (2009)
226
No
mention
Bali Hindu children
exposed to terrorist
bombing, diagnosed
with PTSD. 53.7%
Female
Spiritual
hypnosis
assisted therapy
Single group
session
lasting 30
minutes
No treatment
No mention
Reduced
PTSD
symptoms
Statistically significant main
effect in improvement rate in
hypnotherapy condition. Mean
hyperarousal levels were
statistically different between
two groups, favouring
hypnotherapy condition. Two-
tailed t-test: t(224)= 2.42, p<.05
Abramowitz,
et al., (2008)
32
3%
Male combat
veterans admitted to
PTSD military clinic
with persistent
PTSD symptoms. All
Male
No mention
Two 1.5-hour
sessions per
week for 2
weeks.
Zolpidem (2
weeks)
Specialist in
psychiatry, no
hypnotherapy
qualification
mentioned.
Posttraumatic
Disorder Scale
Statistically significant
improvement rate in
hypnotherapy condition with
PTSD symptoms being lower in
hypnotherapy group compared
to Zolpidem group, p<.0005
30
8.3. Methodological Quality of Included Studies
Each included study was assessed for Risk of Bias and methodological quality
utilising the Cochrane Risk of Bias Tool for Randomised Controlled Trials
(Appendix 4). The findings are presented in Table 3. The methodological quality
was assessed independently by two reviewers. The Cochrane Risk of Bias Tool
has seven criteria, evaluating selection, performance, attrition, detection,
reporting and other bias. The “other bias” refers to bias due to problems not
covered elsewhere, e.g. the study had a possible bias due to study design used
or had been claimed to be fraudulent. Each of these criteria may be reported as
high, low or unclear. The summary assessment of bias may be performed. The
use of scales is discouraged in the Cochrane handbook, as the tool is a domain-
based evaluation where domains are given weight depending on what is
important to consider in the study (Higgins and Green, 2011). According to the
Cochrane handbook guidelines (Higgins and Green, 2011) for subjective
outcomes, such as the symptoms of anxiety disorders, the blinding of
participants is considered important and the following assessment shall reflect
that.
The study by Chiu, et al., (2018) fared overall as of unclear quality due to
unclear information regarding random sequence generation, potentially
introducing selection bias. It was mentioned in the report that patients were
“randomly assigned” but the method was not described. There was no
information on allocation concealment, the personnel or participants were not
blinded, potentially introducing performance bias. Furthermore, participants
randomised to the hypnotherapy condition were given a brief introduction about
the studies aim and methodology before the start of the therapy. No apparent
selective reporting, problems with incomplete data or any other bias were
apparent.
The study by Lesmana, et al., (2009) had issues with randomisation as children
chose randomly which group to participate in. Children “blindly selected
participation in one of the two groups offered to them while not knowing which
one of the two groups they are choosing” (p.26). There was no mention about
31
the blinding of the personnel, potentially introducing performance bias. The
blinding of outcome assessment was unclear as questionnaires were delivered
by psychiatric residents, but it was not mentioned if they were blinded. There
may have been ethical issues as the control group received no treatment; not
even a waiting list was mentioned. There appeared to be no issues with
incomplete outcome data, selective reporting or other bias.
The study by Abramowitz et al., (2008) was unclear about random sequence
generation and allocation concealment. Neither was mentioned in the paper.
The blinding of patients/personnel was not mentioned, neither was the blinding
of outcome assessment. There were no issues regarding incomplete outcome
data or selective reporting. The attrition was explained as one patient withdrew
from the study due to drowsiness caused by Zolpidem. The intention to treat
analysis was not mentioned in the study.
Table 3. Summary of Cochrane Risk of Bias Tool for Randomised Controlled
Trials.
Study
Random
Sequence
Generation
Allocation
Concealment
Blinding of
Participants/
Personnel
Blinding of
Outcome
Assessment
Incomplete
Outcome
Data
Selective
Reporting
Other
Fidelity of
Intervention
Assessed
Chiu, et al.,
(2018)
-
?
-
-
+
+
+
Poor
Lesmana, et
al., (2009)
-
?
?
?
+
+
+
Poor
Abramowitz,
et al., (2008)
?
?
?
-
-
+
+
Poor
Abbreviations: N/A, not applicable; (+), low risk of bias; (-), high risk of bias; (?), unclear risk of bias.
32
9. Discussion
9.1. The Overall Summary of Findings
The objective of this review was to systematically evaluate the relevant evidence
for the effectiveness of hypnotherapy interventions used for treatment of anxiety
disorders. Although the history of hypnotherapy is extensive and there are some
good quality studies and systematic reviews which investigate the effectiveness
of hypnotherapy in pain relief, IBS and many other domains, it was unclear
whether there will be enough good quality research regarding hypnotherapy and
anxiety since the publication and recommendations by Coelho, Canter and Ernst
were published (2007).
The current systematic search discovered only three articles despite a rather
broad search strategy. Studies in this review were collated from a variety of
settings. Participants were from psychiatric and general populations; the age
range was from 6 to 66 years old. The studies varied with respect to the gender
of participants. One study had only male participants and three had more females
than males. All studies that were included had possible baseline differences, when
observing the baseline characteristics tables (age, sex and differences in severity
of illness between groups) and one study did not publish baseline characteristics.
The results of these studies all reported a significant difference in the measured
outcomes favouring hypnotherapy compared to control groups. The results overall
are inconclusive due to the methodological quality of the studies. Similar aspects
of rigorous research were often not reported or conducted. All four studies had
problems regarding blinding and randomisation aspects.
The low volume of RCTs included in the review in turn coupled with the poor
methodological quality would suggest inconclusive evidence to support the
efficacy of hypnotherapy in the treatment of anxiety disorders.
9.2. Review Limitations
33
There are some important limitations of this review. In light of the low volume of
available RCT’s for standalone hypnotherapy intervention, it could be argued that
adjunctive hypnotherapy would have yielded more results. As explained in the
rationale of the systematic review, limiting the type of hypnotherapy only to
cognitive or clinical hypnotherapy may have been an appropriate method to
investigate adjunctive hypnotherapy. As the type of hypnotherapy was not
mentioned in most papers, it would be problematic to assume what kind of
hypnotherapy was utilised. There is a need for research into all types of
hypnotherapy and also the need to highlight the effectiveness of hypnotherapy as
a separate treatment from psychological interventions. Another issue regarding
the review was that the experts who were contacted did not respond to e-mails,
therefore adding nothing to the search.
9.3. Implications for Clinical Practice and Future Research
These findings may have positive implications for clinical practice as
hypnotherapy has been found to be cost-effective, quick and potentially a
promising alternative to medication (Smith, Robinson and Segal, 2017; Huston,
2010; Miller, Fletcher and Kabat, 1995). Children have been found to have a
naturally higher capacity for hypnotherapy (Hawkins and Polemikos, 2002;
Huynh, et.al, 2008; Anbar, 2001) and as side effects are rare (Hudson, 2010), it
would be beneficial to explore this alternative in the treatment of children and
young people as anxiety disorders usually have an early onset (Kessler and
Greenberg, 2002).
To improve the quality of future research in hypnotherapy, when conducting
randomised controlled trials, researchers are encouraged to consider blinding
research staff and participants of the outcomes of the studies. It has been argued
that it is difficult to blind researchers to a hypnotherapy condition and almost
impossible to blind participants to a hypnotherapy condition (Kendrick, et al.,
2013). Kendrick, et al., (2013) recommends sham hypnosis in RCT’s as a
comparison to hypnosis, designing a sham hypnosis condition where participants
are inducted into a hypnotic state and given white noise to listen to instead of
suggestions or treatment.
34
The low volume of RCTs included in the review would indicate that in the past ten
years, despite a vast number of case studies, there were few quantitative studies
conducted regards anxiety treatment with hypnotherapy. A useful future research
suggestion may be to also explore other research designs that outcome the effect
of hypnotherapy for anxiety disorders and PTSD. For example, mixed method
design may draw the strengths and advantages from both qualitative and
quantitative paradigms (Caffery, Martin-Khan and Wade 2017; Creswell, 2015)
possibly providing more in depth and multi-faceted insight into hypnotherapy
treatment.
Clinical hypnotherapy appears to be the most popular due to its meshing with
psychology (Jensen, et al., 2017). As clinicians are more likely to be trained in
research methodology than hypnotherapists and conduct research and publish
articles, there might be an additional bias towards the type of hypnotherapy that
has been researched. To overcome these biases, it may be useful to utilise
hypnotherapists from different types of hypnotherapy interventions to administer
treatment. Additional insight may include the effectiveness of different types of
hypnotherapy in anxiety disorders. Furthermore, it may reduce the reporting bias
and benefit research methodologically. It would appear that the experience or
level of hypnotherapy training of a person/people conducting hypnotherapy is
rarely mentioned in the research papers and it appears to be acceptable that a
qualified psychologist or psychiatrist may practice hypnotherapy without
mentioning any formal training in hypnotherapy. It would be beneficial to integrate
interdisciplinary collaboration in this research area, having well-designed studies,
experienced researchers and experienced hypnotherapists working together.
10. Conclusion
35
Hypnotherapy may have potential to provide a fast, cost-effective alternative to
medication in the treatment of anxiety disorders, especially in children and young
adults. Although research in utilising hypnotherapy generally is promising,
research regarding the use of hypnotherapy for treating anxiety disorders is
insufficient to draw definitive inferences. Therefore, the current review concludes
that the evidence is insufficient to support the effectiveness of hypnotherapy in
treating anxiety disorders and more research using more rigorous methodology is
recommended as a result. The main issue appears to be the quality of RCT’s in
hypnotherapy. Better quality research in the effectiveness of hypnotherapy
appears still be one of the most pressing matters.
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46
Appendix 1
Search Strategy
AMED
(Hypnotherapy OR hypnosis) AND (anxiety disorder* OR GAD OR phobia* OR
post-traumatic stress OR PTSD)
EMBASE and PsychInfo
1. exp Hypnosis/
2. hypnotherap*.ti,ab.
3. exp Anxiety Disorders/
4. Anxiety/
5. exp Stress Disorders, Traumatic/
6. PTSD .ti,ab.
7. OCD .ti,ab.
8. Phobic .ti.ab.
9. Phobias ti.ab.
10. 1 or 2
11. 3 or 4 or 5 or 6 or 7 or 8 or 9
12. 10 and 11
13. limit 9 to yr="2007 -Current"
Ovid MEDLINE ® 1946 to April Week 3 2018
1. exp Hypnosis/di
2. hypnotherap*.mp. [mp=title, abstract, original title, name of substance word,
subject heading word, floating sub-heading word, keyword heading word,
protocol supplementary concept word, rare disease supplementary concept
word, unique identifier, synonyms]
3. exp Anxiety Disorders/di
4. Anxiety disorder*.mp. [mp=title, abstract, original title, name of substance
word, subject heading word, floating sub-heading word, keyword heading word,
protocol supplementary concept word, rare disease supplementary concept
word, unique identifier, synonyms]
47
5. exp Stress Disorders, Traumatic/di
6. PTSD*.mp. [mp=title, abstract, original title, name of substance word, subject
heading word, floating sub-heading word, keyword heading word, protocol
supplementary concept word, rare disease supplementary concept word,
unique identifier, synonyms]
7. 1 or 2
8. or/3-6
9. 7 and 8
10. limit 9 to yr= 2007- Current
CINAHL
TI, AB hypno* AND (TI, AB ptsd OR post traumatic stress disorder OR TI, AB
anxiety disorders OR TI, AB anxiety OR TI, AB phobia*)
Limiters - Publication Year: 2007-2018
Open Grey
(Hypnotherap* OR hypnosis) AND (anxiety OR anxiety disorder* OR GAD OR
phobia* OR post-traumatic OR PTSD)
Cochrane Library
Hypnotherapy* :ti, ab, kw
OR hypnosis :ti, ab, kw
AND anxiet*:ti,ab,kw
OR anxiety disorder*:ti,ab,kw
OR PTSD:ti,ab,kw
(Word variations have been searched)
48
Appendix 2
Inclusion/Exclusion Criteria Form
Study reference:
If all the boxes are ticked, study may be included in the review.
Did the paper meet the inclusion/exclusion requirements for this study? Yes No
INCLUSION CRITERIA
EXCLUSION CRITERIA
Hypnotherapy (any type) as a non-adjunctive
intervention Y
Adjunctive hypnosis (Hypnotherapy combined with
other interventions at the same time e.g. CBT)
N
Any Anxiety Disorder (PTSD, GAD, separation
anxiety disorder, selective mutism, OCD, specific
phobia, panic disorder, agoraphobia)
Y
Paper has observational or qualitative study
design N
Comparator present (any). Y
Experimental studies including but not restricted to
RCTs Y
Outcome is reported Y
Paper published after 2007 Y
49
Appendix 3
Data Extraction Form
Review title or ID
Study ID (surname of first author and year first
full report of study was published e.g. Smith
2001)
Report ID
Report ID of other reports of this study
Notes
General Information
Date form completed
(dd/mm/yyyy)
Name/ID of person extracting
data
Reference citation
Study author contact details
Publication type
(e.g. full report, abstract, letter)
Notes:
Study eligibility
Study
Characteristics
Eligibility criteria
(Insert inclusion criteria for each
characteristic as defined in the Protocol)
Eligibility criteria met?
Location in text or
source (pg &
¶/fig/table/other)
Yes
No
Unclear
Type of study
Randomised Controlled Trial
Quasi-randomised Controlled Trial
Participants
50
Types of
intervention
Types of
comparison
Types of
outcome
measures
INCLUDE
EXCLUDE
Reason for
exclusion
Notes:
DO NOT PROCEED IF STUDY EXCLUDED FROM REVIEW
51
Characteristics of included studies
Methods
Descriptions as stated in report/paper
Location in text
or source (pg &
¶/fig/table/other)
Aim of study (e.g.
efficacy, equivalence,
pragmatic)
Design(e.g. parallel,
crossover, non-RCT)
Unit of allocation
(by individuals,
cluster/ groups or
body parts)
Start date
End date
Duration of
participation
(from recruitment to
last follow-up)
Ethical approval
needed/ obtained for
study
Yes No Unclear
Notes:
52
Participants
Description
Include comparative information for each intervention or
comparison group if available
Location in text or
source (pg &
¶/fig/table/other)
Population description
(from which study
participants are drawn)
Setting
(including location and
social context)
Inclusion criteria
Exclusion criteria
Method of recruitment
of participants (e.g.
phone, mail, clinic
patients)
Informed consent
obtained
Yes No Unclear
Total no. randomised
(or total pop. at start of
study for NRCTs)
Clusters
(if applicable, no., type,
no. people per cluster)
Baseline imbalances
Withdrawals and
exclusions
(if not provided below
by outcome)
Age
Sex
Race/Ethnicity
Severity of illness
Co-morbidities
53
Other relevant
sociodemographics
Subgroups measured
Subgroups reported
Notes:
Intervention groups
Copy and paste table for each intervention and comparison group
Intervention Group 1
Description as stated in report/paper
Location in text or
source (pg &
¶/fig/table/other)
Group name
No. randomised to group
(specify whether no.
people or clusters)
Theoretical basis (include
key references)
Description (include
sufficient detail for
replication, e.g. content,
dose, components)
Duration of treatment
period
Timing (e.g. frequency,
duration of each episode)
Delivery (e.g. mechanism,
medium, intensity, fidelity)
Providers
(e.g. no., profession,
training, ethnicity etc. if
relevant)
Co-interventions
54
Economic information
(i.e. intervention cost,
changes in other costs as
result of intervention)
Resource requirements
(e.g. staff numbers, cold
chain, equipment)
Integrity of delivery
Compliance
Notes:
Outcomes
Copy and paste table for each outcome.
Outcome 1
Description as stated in report/paper
Location in text or
source (pg &
¶/fig/table/other)
Outcome name
Time points measured
(specify whether from
start or end of
intervention)
Time points reported
Outcome definition (with
diagnostic criteria if
relevant)
Person measuring/
reporting
Unit of measurement
(if relevant)
Scales: upper and lower
limits (indicate whether
high or low score is
good)
55
Is outcome/tool
validated?
Yes No Unclear
Imputation of missing
data
(e.g. assumptions made
for ITT analysis)
Assumed risk estimate
(e.g. baseline or
population risk noted in
Background)
Power (e.g. power &
sample size calculation,
level of power achieved)
Notes:
Other
Study funding sources
(including role of funders)
Possible conflicts of interest
(for study authors)
Notes:
Data and analysis
Copy and paste the appropriate table for each outcome, including additional tables for each
time point and subgroup as required.
Dichotomous outcome
Description as stated in report/paper
Location in text
or source (pg &
¶/fig/table/othe
r)
Comparison
56
Outcome
Subgroup
Time point
(specify from start or end
of intervention)
Results
Intervention
Comparison
No. with
event
Total in
group
No. with
event
Total in
group
Any other results
reported (e.g. odds ratio,
risk difference, CI or P
value)
No. missing participants
Reasons missing
No. participants moved
from other group
Reasons moved
Unit of analysis (by
individuals,
cluster/groups or body
parts)
Statistical methods used
and appropriateness of
these (e.g. adjustment
for correlation)
Reanalysis required?
(specify, e.g. correlation
adjustment)
Yes No Unclear
Reanalysis possible?
Yes No Unclear
Reanalysed results
Notes:
For RCT/CCT
57
Continuous outcome
Description as stated in report/paper
Location in text or
source (pg &
¶/fig/table/other)
Comparison
Outcome
Subgroup
Time point
(specify from start or
end of intervention)
Post-intervention or
change from
baseline?
Results
Intervention
Comparison
Mean
SD (or
other
variance,
specify)
No.
participant
s
Mean
SD (or
other
variance,
specify)
No.
participan
ts
Any other results
reported (e.g. mean
difference, CI, P value)
No. missing
participants
Reasons missing
No. participants
moved from other
group
Reasons moved
Unit of analysis
(individuals, cluster/
groups or body parts)
Statistical methods
used and
appropriateness of
these (e.g. adjustment
for correlation)
58
Reanalysis required?
(specify)
Yes No Unclear
Reanalysis possible?
Yes No Unclear
Reanalysed results
Notes:
Continuous outcome
Description as stated in report/paper
Location in text or
source (pg &
¶/fig/table/other)
Comparison
Outcome
Subgroup
Time point
(specify from start or
end of intervention)
Post-intervention or
change from
baseline?
Results
Intervention
Comparison
Mean
SD (or
other
variance,
specify)
No.
participants
Mean
SD (or
other
variance,
specify)
No.
particip
ants
Any other results
reported (e.g. mean
difference, CI, P value)
No. missing
participants
59
Reasons missing
No. participants
moved from other
group
Reasons moved
Unit of analysis
(individuals, cluster/
groups or body parts)
Statistical methods
used and
appropriateness of
these (e.g. adjustment
for correlation)
Reanalysis required?
(specify)
Yes No
Unclear
Reanalysis possible?
Yes No
Unclear
Reanalysed results
Notes:
Other outcome
Description as stated in report/paper
Location in text or
source (pg &
¶/fig/table/other)
Comparison
Outcome
Subgroup
60
Time point
(specify from start or end
of intervention)
No. participants
Intervention
Control
Results
Intervention
result
SE (or other
variance)
Control
result
SE (or
other
variance)
Overall results
SE (or other variance)
Any other results
reported
No. missing participants
Reasons missing
No. participants moved
from other group
Reasons moved
Unit of analysis (by
individuals,
cluster/groups or body
parts)
Statistical methods used
and appropriateness of
these
Reanalysis required?
(specify)
Yes No
Unclear
Reanalysis possible?
Yes No
Unclear
Reanalysed results
61
Notes:
Other information
Description as stated in report/paper
Location in text
or source (pg &
¶/fig/table/othe
r)
Key conclusions of study
authors
References to other
relevant studies
Correspondence required
for further study
information (from whom,
what and when)
Notes:
62
Appendix 4
Risk of Bias assessment
See Chapter 8 of the Cochrane Handbook. Additional domains may be added for non-randomised
studies.
Domain
Risk of bias
Support for judgement
(include direct quotes where available with
explanatory comments)
Location in text
or source (pg &
¶/fig/table/other)
Low
High
Unclear
Random sequence
generation
(selection bias)
Allocation
concealment
(selection bias)
Blinding of participants
and personnel
(performance bias)
Outcome group: All/
(if separate judgement
by outcome(s)
required)
Outcome group:
Blinding of outcome
assessment
(detection bias)
Outcome group: All/
(if separate judgement
by outcome(s)
required)
Outcome group:
Incomplete outcome
data
(attrition bias)
Outcome group: All/
(if separate judgement
by outcome(s)
required)
Outcome group:
Selective outcome
reporting?
(reporting bias)
63
Other bias
Notes:
Appendix 5
Example Letter to Experts.
64
Dear Sir/Madam/Dr/Prof,
I am a research methodology masters student and also a practicing hypnotherapist. I am
currently writing a systematic review on the topic of effectiveness of hypnotherapy in anxiety
disorders and subsequently trying to identify unpublished research regarding the topic.
I have identified you as one of the experts on the field and read your paper on XXXXX. I would
greatly appreciate your assistance in informing me in potential sources/ researchers who have
access to any unpublished literature in this matter.
Many Thanks,
65
Appendix 6.
Characteristics of excluded studies
Study
Reference
Reason for
Exclusion
Study Design
Study Aim
Number of
Participants
Results
Huston, 2010
Not having a
randomised
or non-
randomised
experimental
study design.
Pre-post
intervention (data
collected
retrospectively).
The null hypothesis stated that there will be no
difference in the reduction of anxiety levels between the
hypnotherapy clients and the cognitive-behavioral
therapy clients as evidenced by scores on the Beck
Anxiety Inventory (BAI), as well as the null hypothesis
that hypnosis will be effective in reducing anxiety levels
in clients diagnosed with generalized anxiety disorder
60
Hypnosis and CBT treatments did not have a
differential impact on changes in BAI scores from pre-
test to post-test. Both treatment groups evidenced a
decrease in BAI scores from pre-test to post-test. This
supports the null hypotheses.
Alladin, 2016
Not having a
randomised
or non-
randomised
experimental
study design.
Case descriptions
Describing the benefits of cognitive hypnotherapy as
used in researchers practice
N/A
Demonstration on how to integrate cognitive,
behavioural, mindful, psychodynamic and hypnotic
strategies and to choose “best fit” strategies for a
particular patient
Daitch, 2018
Not having a
randomised
or non-
randomised
experimental
study design.
Case study
Describing the treatment of a patient with panic disorder
with mindfulness, hypnosis and cognitive therapy
1
Patient continues therapy but has been reported to
experience the reduction of symptoms.
66
