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The placebo effect and why it really does matter

    What is it?

    You may have heard of “placebo” or the “placebo effect” in relation to drug trials where some of the participants were given the active drug and others were given sugar pills or other inactive agents, with the purpose of comparing the two results.

    The placebo effect covers a bit more than that. The effect can extend beyond drug trials to any instance where the patient is getting better and yet the reason cannot be assigned to the treatment he or she is receiving. It would seem that the expectations of the practitioner and the patient can work in ways not fully understood.

    The following video by Emma Bryce, ‘The power of the placebo effect’, gives an easy to understand explanation of it.

    How big an effect is it?

    The placebo effect apparently varies based on the disease or condition being addressed and the type of treatment, whether it be tablet, injection, surgery or something else.

    A large review of antidepressant trials in 2016 found that the placebo response was from 35% to 40%.

    “We identified 252 placebo-controlled trials (26 324 patients on placebo) done between 1978 and 2015. There was a structural break in 1991, and since then, the average placebo response rates in antidepressant trials have remained constant in the range between 35% and 40%”.

    Furukawa TA et al. Placebo response rates in antidepressant trials: a systematic review of published and unpublished double-blind randomised controlled studies. 2016. 1

    Other researchers report even higher figures in some cases, but even so, there seems to be a lot of variation in reports which seems to indicate a closer look is needed.

    The effect is apparently even more evident in the area of physical diseases:

    “The results suggest that placebo interventions can improve physical disease processes of peripheral organs more easily and effectively than biochemical processes. In total, 50% of trials measuring physical parameters showed significant placebo effects, compared with 6% of trials measuring biochemical parameters…”

    Karin Meissner, Hans Distel & Ulla Mitzdorf. Evidence for placebo effects on physical but not on biochemical outcome parameters: a review of clinical trials. 2007. 2

    Its influence on psychiatry is large

    Any research or investigation where 35% or more of the results were due to a factor that one did not fully understand is surely incomplete. Whether one is a psychiatric researcher, investigator or consumer, the placebo effect is a ‘mystery’ variable and the size of the effect demands attention.

    There are currently controversies ongoing in psychiatry regarding the effectiveness of ECT and SSRIs when compared to placebo.

    “To summarize, there is a strong therapeutic response to antidepressant medication. But the response to placebo is almost as strong. This presents a therapeutic dilemma. The drug effect of antidepressants is not clinically significant, but the placebo effect is. What should be done clinically in light of these findings?”

    Kirsch I. Antidepressants and the Placebo Effect. 2014. 3

    “There is still no evidence that ECT is more effective than placebo for depression reduction or suicide prevention. Given the well-documented high risk of persistent memory dysfunction, the cost-benefit analysis for ECT remains so poor that its use cannot be scientifically, or ethically, justified.”

    J Read and C Arnold. Is Electroconvulsive Therapy for Depression More Effective Than Placebo? A Systematic Review of Studies Since 2009. 2017. 4

    Quite simply, the placebo effect has potentially a very large influence on the tools of psychiatry, and no matter what side of these arguments you are on, this again deserves a closer look.

    Conclusion

    Any research or investigation where 35% or more of the results were due to a factor that one did not fully understand is surely incomplete. Whether one is a psychiatric researcher, investigator, or consumer, the placebo effect is a ‘mystery’ variable and the size of the effect demands attention.

    But no one it seems, will roll up their sleeves and find out just what it is and how to use it.

    Further references:

    Antipsychotic drugs

    Antipsychotics – a horrible replacement for even worse alternatives

    When the first antipsychotic, chlorpromazine, emerged in the 1950s it was gleefully described by psychiatrists as a ‘chemical lobotomy’ – as though this was something to aim for …
    A hand pouring pills into a person's head

    Chemical imbalance – psychiatry as a pharma marketing tool

    Despite hundreds, if not thousands of contributions from psychiatrists in support of the chemical imbalance theory, some leading voices in the field deny there ever was a theory and the public have been misled …

    1. Furukawa TA, Cipriani A, Atkinson LZ, Leucht S, Ogawa Y, Takeshima N, Hayasaka Y, Chaimani A, Salanti G. Placebo response rates in antidepressant trials: a systematic review of published and unpublished double-blind randomised controlled studies. Lancet Psychiatry. 2016 Nov;3(11):1059-1066.
    2. Karin Meissner, Hans Distel & Ulla Mitzdorf Evidence for placebo effects on physical but not on biochemical outcome parameters: a review of clinical trials. BMC Medicine volume 5, Article number: 3 (2007)
    3. Kirsch I. Antidepressants and the Placebo EffectZ Psychol. 2014;222(3):128-134.
    4. Is Electroconvulsive Therapy for Depression More Effective Than Placebo? A Systematic Review of Studies Since 2009” 2017. Ethical Human Psychology and Psychiatry 19(1):5-23.