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Guidelines for Evidence-Based Practice
Clinical Hypnotherapy & Hypno-Psychotherapy

“I beg farther to remark, if my theory and pretensions, as to the nature, cause, and extent of the phenomena of [hypnotism] have none of the fascinations of the transcendental to captivate the lovers of the marvellous, the credulous and enthusiastic, which the pretensions and alleged occult agency of the mesmerists have, still I hope my views will not be the less acceptable to honest and sober-minded men, because they are all level to our comprehension, and reconcilable with well-known physiological and psychological principles.” 

– James Braid, Hypnotic Therapeutics, 1853

This booklet is designed to explain the concept of evidence-based practice in relation to hypnotherapy and hypno-psychotherapy, and to provide guidelines for therapists seeking to adopt a more evidence-based approach.

What is Evidence-Based Practice?

By evidence we primarily mean information gained from credible scientific research studies, including clinical trials and experimental studies.  An influential definition was provided by Sackett et al. (2000): “Evidence-based practice is the integration of best research evidence with clinical expertise and patient values.”

A recent editorial in the British Medical Journal defined Evidence-Based practice as follows,

Evidence based medicine is the conscientious, explicit, and judicious use of current best evidence in making decisions about the care of individual patients.  The practice of evidence based medicine means integrating individual clinical expertise with the best available external clinical evidence from systematic research.

The team of authors add the following remarks regarding evidence-based practice in general medicine which, in our view, apply equally well to the practice of hypno-psychotherapy,

Good doctors use both individual clinical expertise and the best available external evidence, and neither alone is enough.  Without clinical expertise, practice risks becoming tyrannised by evidence, for even excellent external evidence may be inapplicable to or inappropriate for an individual patient.  Without current best evidence, practice risks becoming rapidly out of date, to the detriment of patients.  (‘Evidence based medicine: what it is and what it isn't’, Editorial, BMJ 1996; 312:71-72)

As the founder of Cognitive Therapy, Aaron Beck, argues, to a large extent scientific method can be seen as a refinement and extension of ordinary “common sense.” 

In his approach to external problems, man is a practical scientist: He makes observations, sets up hypotheses, checks their validity, and eventually forms generalisations that will later serve as a guide for making rapid judgements of situations. […] Throughout his development, man repeatedly uses the prototype of the experimental method –without recognising it.  (Beck, 1976: 12)

Likewise, all therapists, necessarily, already formulate and check hypotheses in their own, individual clinical practice.  Weitzenhoffer, one of the leading authorities on hypnotism, writes, 

Why this emphasis upon a scientific approach?  It is because the scientific method, which in many instances, is just good plain common sense, has been found this far to be the best available method, certainly the most suitable, for the acquisition of useful, effective, knowledge.  (Weitzenhoffer, 2000: 18)

The Evidence-Based philosophy merely encourages clinicians to reflect on this process and develop it to embrace more a sophisticated way of interpreting the data of their own experience and that of others.

Clinical practice is fundamentally the applied branch of the science of health.  In view of the success of the applied branches of other sciences, should we not seriously consider an applied branch for the science of health along the lines of the definitions just given?  Should that not then be what we as “clinicians” should practice?  Can any psychotherapist seriously consider carrying out her work without giving due consideration to those scientifically established facts that pertain to her practice?  (Weitzenhoffer, 2000: 19)

From the 1990s onward, “evidence-based” approaches to treatment have become increasingly popular.  Increasingly, this trend is extending to the practice of psychotherapy and hypnotherapy.  The official National Occupational Standards require hypnotherapists to be competent in designing treatment plans based upon ‘evidence from documented research and the success of the interventions concerned.’ (NOS, Element CH-H1.4).  The Standards also require hypnotherapists to know and understand ‘the information available on effective complementary healthcare and how to evaluate and use this information within [their] own practice.’ (NOS, Knowledge & Understanding, E2-3.)

Do Therapists Intuitively Know What Works?

Sometimes therapists object that they can tell what works and what doesn’t simply by observing their own experiences without looking at other people’s research.  Personal clinical experience is an essential factor in deciding how to help clients but there are other factors which need to be considered,

1.    Confirmation bias.  There is a well-documented tendency for people to look for evidence to support their own presuppositions.  Therapists need to be careful to ask themselves whether they are interpreting evidence in the way other people would, or being selective in a way that merely confirms their own prejudices.


2.    Failure to follow-up.  It is normal practice to measure the success of treatment after 6 weeks, 6 months, or even a year or more.  Therapists who base their judgement only on the feedback received from clients during sessions, and not on long-term measures, are very likely to statistically over-estimate the success of treatment as a result.


3.    Absence of real-world exposure.  Some therapists carry out treatment without asking clients to test their improvement out in the real world, in vivo.  Clients may report feeling better in sessions but relapse when they encounter the situations which previously triggered their problem.  For example, a phobic might not know how much improvement they have made until they have tried to face their fears in reality, outside of the consulting room.


4.    Non-specific factors.  Research consistently shows that many different forms of therapy have broadly similar success rates, despite using an enormous variety of theories and techniques.  The factors which psychological therapies have in common, their “non-specific” factors, are therefore likely to account for most of the perceived benefits of treatment.  For example, clients’ expectations about improvement, emotional support, therapist reassurance, etc., are such non-specific factors.  Therapists need to compare their success with a given technique against meaningful baseline figures, therefore, in order to know whether client improvement is due to the specific techniques used, or to non-specific elements in the therapeutic relationship.  Assuming that a technique “works” simply because a client gets better afterwards is known in philosophy of science as the post hoc ergo propter hoc fallacy, from the fact that someone gets better after a therapy technique it does not follow that they got better because of the therapy technique.


5.    Measurement bias.  Certain ways of measuring client improvement may mislead therapists.  In particular, over-dependence upon a single measurement of client improvement, especially a single subjective measurement such as a SUD (subjective units of disturbance) scale, may create exaggerated estimates of client improvement.  In research, it is common practice to employ a battery of tests, e.g., validated questionnaires, physiological measures, and observation of behaviour change in order to arrive at a more reliable measurement of a treatment’s effects.

Evidence-based practice doesn’t mean ignoring your own personal observations, just being careful to interpret things as objectively as possible, and acknowledging what other people have found when they have carried out research in similar areas.

Recommendations for Evidence-Based Hypno-Psychotherapy

There are a number of recommendations that can be made to therapists seeking to adopt an Evidence-Based approach to their practice.

1.    Evidence-Based Theory.  Aim to interpret the practice of therapy primarily in terms of credible, modern and mainstream scientific research, insofar as it is possible to do so, e.g., in the fields of health science, psychology and neurology. 

2.    Occam’s Razor.  Theories should be avoided, or at least questioned, which depend upon reference to pseudoscientific concepts or unnecessary/unverifiable hypotheses.  Psychotherapeutic theories, that is, should be consistent with the law of scientific parsimony, or “Occam’s Razor”, which states: “Entities are not to be multiplied without necessity.”  This principle requires that before new or controversial concepts are introduced it must first be confirmed that established ones are incapable of explaining the phenomena in question.  In developing 19th century hypnotism, James Braid applied Occam’s Razor by demonstrating that the new and controversial concept of “animal magnetism” was unnecessary to explain the therapeutic improvements and other effects observed.  Instead Braid demonstrated that “well-established” concepts like expectation, imagination, suggestion, attention, habit formation, etc., were sufficient to account for the observable phenomena produced.  Hence Braid wrote, ‘There is, therefore, both positive and negative proof in favour of my mental and suggestive theory, and in opposition to the magnetic, occult, or electric theories of the mesmerists and electro-biologists.  My theory, moreover, has this additional recommendation, that it is level to our comprehension, and adequate to account for all which is demonstrably true, without offering any violence to reason and common sense, or being at variance with generally admitted physiological and psychological principles.’  (Braid, 1851).


3.    Evidence-Based Practice.  Utilise therapeutic techniques supported by a credible and comprehensive interpretation of relevant research in this area, insofar as it is reasonable and practicable to do so.  Eschew the use of techniques which have generally been shown to lack empirical support, or which research has suggested may be harmful, insofar as it is consistent with the well-being and best interests of the client, and other ethical considerations, to do so.


4.    Research Journals.  Keep abreast of current research in your field by subscribing to one of the leading research journals, e.g., The International Journal for Clinical & Experimental Hypnosis (IJCEH).  These provide essential information on the latest research studies reviews with respect to the clinical practice of hypnotherapy. 


5.    Clinical Textbooks.  It is also important to study other contemporary sources of evidence-based theory and practice, such as books published recently, i.e., within the last ten years or so, and written by credible authors.  Credible psychotherapy textbooks should be expected to reference a range of similar books and journal articles in their bibliography section, and this can be taken as a rough indication of the breadth and quality of research upon which they are based.  Well-established texts will often have gone through several editions, such as the current 4th edition of Hartland’s Medial & Dental Hypnosis by Heap & Aravind.  The best hypno-psychotherapy textbooks are often quite specialist hardback publications and may therefore be expensive.  Important textbooks are sometimes out of print, but most may be easily obtained from large online booksellers.


6.    Research Methods.  Have at least a basic understanding of psychotherapy and medical research methods, sufficient to be able to interpret the meaning of articles in contemporary research journals.  An understanding of the research issues relating to psychotherapy and hypnotherapy will also help you to interpret the outcome of your own interventions.


7.    Clinical Supervision.  Make use of formal clinical supervision to review your practice and discuss the outcomes in relation to research in the field.  For instance, supervision offers an ideal opportunity to discuss how research might guide clinical decisions you make with regard to the interventions used to help a specific client.


8.    Continual Professional Development (CPD).  All hypnotherapists should attempt to maintain their appreciation of developments in the field through ongoing training and professional development.  This may consist of attending high-quality CPD training or professional conferences, etc. 


Evidence-based practice is not meant to replace clinical skill and experience but to supplement and inform it.  The interests of the client are paramount.  Every client, however, has the right to expect a high standard of care from their therapist.  That includes the expectation that the therapist should be informed with regard to research in his field, and basing his actions upon a considered interpretation of credible scientific research.

One need not kowtow blindly to “science.”  Still, we must recognise that there is an implicit contract between practitioners in psychology and psychiatry and the clients who seek their help.  This involves the assumption that the techniques of mental health specialists are based on scientific grounds. […] In this sense, it is a very profound responsibility of the clinical practitioner that he be in position to show some of the ties between what he practices and the background of formal theory that makes up the body of knowledge in his field.   (Singer, 1974: 5)

Please contact the Register for Evidence-Based Hypnotherapy & Psychotherapy (REBHP) for further information or advice. 


Beck, A.          (1976).  Cognitive Therapy & The Emotional Disorders.

Braid, J.           (1851).  Electro-Biological Phenomena, etc.

Braid, J.           (1853).  Hypnotic Therapeutics.

Sackett, D. L., Straus, S. E., Richardson, W. S., Rosenberg, W., & Haynes, R. B. (2000).  Evidence based medicine: How to practice and teach EBM, 2nd edition.

Singer, J.L.      (1974).  Imagery & Daydream Methods in Psychotherapy & Behaviour Modification.

Weitzenhoffer, A.        (2000).  The Practice of Hypnotism.