Does hypnotherapy/hypnosis, in any form, for any type of disorder, work? Does Hypnosis Work for Treating, or Curing, any Form of any Mental Disorder?

Let's say my definition of hypnosis is related mostly to the classical way people think about it.  This is subjective of course, but I've purposefully made it that way. I do realize at times it may overlap into other types of therapy as well.

If there are other forms of hypnosis I'd like to hear about those too though!

Citation/Research Wise:


I'd like to know if its backed by literature.  I want the specific citation's abstract   quoted.
I'd like to know their findings, conclusions, and methodologies and your analysis of that.
I'd like to know how long the treatments lasted after they stopped being hypnotized.
I'd like to know how effective it was for whatever specific goals that it was used to treat.  How long did the affects last if there were any?
I'd like to know if you found any potential errors or flaws in the study - and you're overall analysis of that.




Citing Wikipedia is not an acceptable answer or comment as it is not a reputable source, it's citations are.  If you are going to do that, pick the most compelling and valid studies (no matter the disorder), or something like a meta analysis that Wikipedia cites and then post that along with the answer to the above questions.  Thanks.



Anecdotally:


I'd like to know what it feels like to be hypnotized if you've had the experience of it.
I'd like to know why if it worked really well for you then why did you stop doing it or have you actually continued?


It can be any disorder of any kind, just as long as someone could classify it as a psychological "problem" in some context.  The more angles you come at it with the better though.
Hypnosis "works" only insofar as it induces1 a trance. Hypnosis is not a type of therapy. Hypnosis does not cure any disorders or do anything at all, except induce a trance.

Hypnotherapy, from the perspective of psychodynamic theory, utilizes this trance to directly access the subconscious. In traditional hypnotherapy (of the Victorian era), direct suggestions were "planted" in the "unprotected" subconscious; in modern Ericksonian hypnotherapy, the unconscious is stimulated to participate in the healing process.

So the question we are dealing with asks:

Does hypnotherapy work for any type of disorder?

Yes, it does. Standard works (Burrows &amp; Dennerstein, 1980; Brown &amp; Fromm, 1986; Cheek &amp; LeCron, 1968; Crasilneck &amp; Hall, 1985; Hammond, 1990; Kossak, 1989; Kroger &amp; Fezler, 1976; Peter et al., 1991; Revenstorff, 1993; Lynn et al., 1996; Wester &amp; Smith, 1984; Erickson, 2007-2010; O'Hanlon &amp; Hexum, 1990) show that hypnosis has been successfully applied to a multitude of psychosomatic, psychiatric and somatic cases including:


behavioral problems

nail biting
enuresis (bedwetting)
smoking
overweight
academic and athletic increase in performance

psychoneurotic disorders

phobias, obsessive-compulsive disorders
depressive reactions
post-traumatic stress disorder
dissociative disorders
sleep disorders

psychosomatic disorders

chronic pain
migraine, tension headache
morbus crohn, ulcers
asthma, hay fever
hypertonia (high blood pressure)

somatic disorders

immunology: warts, dermatosis, ichtyosis, tumors
vasomotoric: bleeding control, morbus raynaud, wound healing
acute pain: obstetrics, dentistry, postoperative pain
neurology: amnesia, rehabilitation after brain lesions



In addition to case studies, there is a growing number of controlled group studies on the effectiveness of hypnotherapy which show empirically confirmed indications for this method. Meta-analyses have become the accepted method of judging the effectiveness of a therapeutic procedure, so I will confine myself to these in the following overview.

In a meta-analysis (Rominger, 1995) of 36 control group studies with more than 1200 patients  the effect sizes ranged from g = .54 to g = .952. This corresponds (converted after Rosenthal, 1984) to a correlation between treatment and effect ranging from r = .26 to r = .44. From this a success rate (in %) can be estimated for treated and untreated patients (table 1).

                 Number of Studies    Success Rate    Success Rate
                                      untreated (%)   treated (%)
all studies      36                   31              69
smoking           4                   30              70
anxiety           6                   29              71
pain             14                   37              63


Table 1. Results of a meta-analysis of hypnotherapy (after Rominger, 1995).

In a more recent meta-analysis, Bongartz et al. (1999) found comparable results in 112 studies with 5600 patients (table 2).

                       Number of Studies    Success Rate    Success Rate
                                            untreated (%)   treated (%)
psychotherapy (all)    85                   32              68
addiction               6                   37              63
somatoform disorders   11                   35              65
anxiety                11                   26              74
behavioral problems     4                   33              67
pain (all)             27                   35              65
pain (cancer)           6                   36              64
pain (surgery)          8                   38              62
pain (birth)            5                   36              64


Table 2. Results of a meta-analysis of hypnotherapy (after Bongartz et al., 1999).

In a new meta-analysis (2002), Bongartz et al. again confirmed the effectiveness of hypnotherapy. The abstract recapitulates:


  From 193 studies published until 1998 that investigated the efficacy
  of hypnosis 43 randomized clinical studies were selected that compared
  a patient group treated exclusively by hypnosis with an untreated
  control group (or with a group of patients treated by conventional
  medical procedures).The 43 studies were integrated into a
  meta-analysis that yielded a weighted average post-treatment effect
  size of d=.60 (medium effect size) for hypnotic treatment of ICD-10
  coded disorders (24 studies; average treatment period: 5.1 weeks)
  and d=.38 (small effect) for hypnosis as an adjunct for supporting
  medical procedures (19 studies).These estimates are conservative
  since all variables of a given study were used. Most of the studies
  employed methods of the classical approach to hypnosis. In order to
  obtain an estimate to which extent non-clinical factors
  (design-quality, way of comparison of dependent variables) have an
  influence on the effect sizes, effect sizes were computed for all
  studies of the original 193 studies that reported the necessary
  statistical information (N=89). For those studies with an average
  effect size of d=.80 a mas- sive influence of non-clinical factors was
  demonstrated with a range from d=.51 for randomized studies with group
  comparisons to d=2.0 for non-randomized studies using
  pre-post-comparisons.


A table listing all 43 analyzed studies and their area of application ("Störungsbild/Anwendungsbereich"), number of patients ("Patientenzahl"), type of hypnosis ("Hypnoseart"), treatment period in weeks ("Behandlungszeitraum") and effect sizes ("Effektstärke") is included in the publication which is available online at http://bscw.rediris.es/pub/bscw.cgi/d4416025/Bongartz-Effektivitat_hypnose.pdf (in German). It gives a more discriminating view and shows the large variance in effect sizes among the studies, but does not add anything new to this overview.

All the studies included in the meta-analysis used a control group, randomized assignment of patients to the groups, and used hypnotherapy as the only psychotherapeutic treatment (and not in conjunction with other forms of psychotherapy), but sometimes in conjunction with the medical standard therapy. As such, from my point of view, the meta-analysis is quite flawless. Some of the studies included measurements taken some time after the end of the treatment, but these were not considered in this meta analysis, because the 193 studies from which the ones included in the meta-analysis were selected are all the studies that the authors could find in relevant databases and literature ("footnote chasing") between 1974 and 1998, and the number of studies including "longer-term" effects were apparently not enough for a separate analysis. Thus, the authors of the meta-analysis considered only the immediate post-treatment measures of all studies.

In summary, it seems to me that the effectiveness of hypnotherapy has been shown especially for behavioral, anxiety and (psycho)somatic disorders and symptoms, while it seems not to have been applied, or not successfully, to psychotic, affective, dissociative, sexual, eating, sleep, impulse control, adjustment and personality disorders.



Footnotes:

1 Sometimes. An attempt by a clinical psychologist and trained hypnotist to hypnotize me did not lead to any trance.

2 In an analysis of 302 meta-analyses of psychologica, pedagogical and behavioral therapies, Lipsey and Wilson (1993) found 90% of effect sizes to be above 0.10, and 85% above 0.20. A more methodically severe selection of 156 meta-analyses returned a mean effect size of 0.47.



Sources:


Bongartz, W., Flammer, E., &amp; Schonke, R. (1999). Die Effektivität der Hypnotherapie: Eine meta-analytische Studie. Vortrag auf der Jahrestagung der M.E.G., Bad Orb.
Bongartz, W., Flammer, E., &amp; Schonke, R. (2002). Die Effektivität der Hypnose: Eine meta-analytische Studie. Psychotherapeut, 47, 67-76.
Brown, D. P., &amp; Fromm, E. (1986). Hypnotherapy and Hypnoanalysis. Hillsdale, NY: Lawrence Erlbaum.
Burrows, G. D., &amp; Dennerstein, L. (Eds.) (1980). *Handbook of hypnosis and psychosomatic medicine. Amsterdam: Elsevier.
Cheek, D. B., &amp; LeCron, L. M. (1968). Clinical hypnotherapy. New York: Grune &amp; Stratton.
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