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Archived Comments for: Homeopathy for mental fatigue: lessons from a randomized, triple blind, placebo-controlled cross-over clinical trial

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  1. Homeopathy for mental fatigue ¿ another trial of poor external and model validity

    Petter Viksveen, University of Sheffield

    1 February 2013

    Homeopathy for mental fatigue ¿ another trial of poor external and model validity.
    Comment by Viksveen P, Fibert P.

    In a recently published trial, researchers found no effect of a homeopathic medicinal product (HMP) in treatment of participants with mental fatigue (Dean et al. 2012). Although the trial¿s internal validity was fairly high and risk of bias was low, its external validity and model validity were poor.

    A single dose of the homeopathic medicinal product Kali phosphoricum 6x was tested in a triple-blinded randomised placebo-controlled cross-over trial. Participants received either verum or placebo on day 1 and were seven days later crossed-over to the opposite group. As the authors rightly point out, the trial does not test so-called 'classical' homeopathy, where an individual patient is prescribed a homeopathic remedy specifically adjusted according to the patients¿ complete symptom picture. The authors refer to 'clinical' homeopathy, where individual HMPs may be prescribed to a group of patients suffering from the same condition.

    The authors¿ choice of treatment modality is based on a former trial (Strauss 2000) reported in a Cochrane review (Heirs and Dean 2007), which showed that Kali phos. had been used as a component of a complex remedy in patients diagnosed with attention deficit hyperactivity disorder (ADHD). The trial reported significant time effects for verum, but not placebo, when testing participants¿ ability to respond correctly to a 'checking task'. However, Heirs and Dean were in their review unable to find significant differences on recalculating original data to test inattention. It is therefore not clear why a further trial was merited. There were other trials in the review which we suggest were more worthy of reference. Replicating part of a trial that demonstrated neither significant results nor external validity appears a waste of scarce research resources.

    Further, Dean et al.¿s (2012) trial did not recruit ADHD patients, as the authors had difficulties obtaining ethics approval for inclusion of this group of patients. It is therefore unclear why the authors referred to a previous ADHD trial, when testing non-ADHD participants.

    Homeopathy is typically recommended in treatment of chronic complaints and practitioners claim it has long-term effects which need to be assessed over a longer period of time. Indeed in a pre-trial study, Frei et al. (2005) found it took an average 5.1 months for a suitable individualised remedy to be found for children with ADHD, and effects noticed. Dean at al.¿s (2012) trial involved a test carried out immediately after taking a single dose of the homeopathic medicinal product. Although homeopathy is used in acute treatment of certain complaints, the participants in this particular study did not report any acute symptoms. On the contrary, mental fatigue more commonly develops over a longer period of time. Moreover, the use of a single dose in 6x potency of a homeopathic remedy is likely to be insufficient to result in a significant response. In low potencies, repeated doses are usually required.

    For future studies we hope that researchers will carefully consider guidelines for the external validity and model validity of planned trials. Examples of such guidelines have been published by other authors (Bornhoeft et al. 2006, Mathie et al. 2012). Homeopathic research is in need of good quality trials which retain a balance between external and internal validity, and of replication of successful rather than unsuccessful results. Moreover, we take the opportunity to point out that systematic reviews and meta-analyses of homeopathy such as the one referred to by the authors of this trial, should clearly differentiate between 'clinical' and `classical¿ homeopathy. The two approaches are significantly different and their results should not be pooled. 'Clinical' homeopathy misses key aspects of 'classical' homeopathy, including the principle of individualisation, the homeopathic consultation and the therapeutic encounter (Relton et al. 2008).


    Bornhoeft G, Maxion-Bergemann S, Wolf U, Kienle GS, Michalsen A, Vollmar HC, Gilbertson S, Matthiessen PF. Checklist for the qualitative evaluation of clinical studies with particular focus on external validity and model validity. BMC Medical Research Methodology 2006, 6:56 doi:10.1186/1471-2288-6-56

    Dean ME, Karsandas R, Bland JM, Gooch D, MacPherson H. Homeopathy for mental fatigue: lessons from a randomized, triple blind, placebo-controlled cross-over clinical trial. BMC Complementary and Alternative Medicine 2012; 12:167. doi:10.1186/1472-6882-12-167.

    Frei H, Everts R, von Ammon K, Kaufmann K, Walter D, et al. Homeopathic treatment of children with attention deficit hyperactivity disorder: a randomised, double blind, placebo controlled crossover trial. Eur J Pediatr 2005; 164:758-767.

    Heirs M, Dean ME. Homeopathy for attention deficit/hyperactivity disorder or hyperkinetic disorder. Cochrane Database of Systematic Reviews 2007, Issue 4. Art. No.: CD005648. doi:10.1002/14651858.CD005648.pub2.

    Mathie RT, Roniger H, Van Wassenhoven M, Frye J, Jacobs J, et al. Method for appraising model validity of randomised controlled trials of homeopathic treatment: multi-rater concordance study. BMC Medical Research Methodology 2012; 12:49. doi:10.1186/1471-2288-12.49

    Relton C, O¿Cathain A, Thomas KJ. Homeopathy: Untangling the debate. Homeopathy 2008; 97:152-155.

    Strauss LC. The efficacy of a homeopathic preparation in the management of Attention Deficit Hyperactivity Disorder. Biomedical Therapy 2000; 18(2):197-201.

    Competing interests


  2. Doomed to prove nothing from the start

    Stephen Gordon, European Central Council of Homeopaths

    18 February 2013

    I welcome this very apposite critique from Petter Viksveen of the above named paper. The research project the authors set up was very poorly conceived and doomed from the start to prove nothing about homeopathy one way or the other. What is disappointing is that so much time, energy and money went into such a project when it could have been invested in a far better piece of methodology that could have given useful results in a field that needs the investment.

    Competing interests