Faculty of 1000

Post-publication peer review

Smells like teen spirit

Posted by rpg on 8 January, 2010

ResearchBlogging.org An interesting evaluation winged its way into Editorial over the Christmas break, and got waved under my nose ahead of publication. According to a paper published in J Clin Psychopharmacol last August, a double-blind placebo-controlled trial of oral chamomile extract showed a modest anxiolytic activity in patients with mild to moderate generalized anxiety disorder.

Despite the study’s small sample size (and the modesty of the authors) it seems to be a reasonable trial, and looks like chamomile is actually beneficial over placebo, in its first randomized, double-blind, placebo-controlled, parallel-group trial. This is big news for herbal therapies (yes Virginia, they do have active ingredients; unlike homeopathic prepartions).

However, the authors also say

We did not use a specific patient or clinician-rated measure
to verify the adequacy of the blinded conditions. Thus, it is possible that unrecognized rater or patient or clinician bias may have contributed to the superiority of chamomile over placebo

(my emphasis)

which leads me onto something a friend pointed out when I brought the paper to her notice. Chamomile has a reasonably strong and distinctive odour and flavour. If the preparation used retained either of these, then the placebo effect could still be in play.

I have finally managed to get hold of the full paper, however, and deep in the Materials section I find

Blinding of the characteristic chamomile aroma was achieved by inserting a disk impregnated with 1 drop of chamomile oil (for placebo) or 1 drop of neutral oil (for chamomile) into the lid of each airtight medication container

which is a great start, but I don’t know if it would be enough. Anyone have any thoughts on this?

Amsterdam, J., Li, Y., Soeller, I., Rockwell, K., Mao, J., & Shults, J. (2009). A Randomized, Double-Blind, Placebo-Controlled Trial of Oral Matricaria recutita (Chamomile) Extract Therapy for Generalized Anxiety Disorder Journal of Clinical Psychopharmacology, 29 (4), 378-382 DOI: 10.1097/JCP.0b013e3181ac935c


7 Responses to “Smells like teen spirit”

  1. DaWintle said

    What’s “neutral oil”? Does it smell like chamomile, different, or of essentially nothing?

    I predict this study will (a) not be replicated, and (b) find its way into the popular press lexicon of things that people believe because “it was published by scientists” (viz. benefits/harms due to coffee, red wine, oat bran, and MMR vaccinations).

    • rpg said

      I don’t know the answer to that question. I would like to.

      Isn’t that prediction a little harsh? Aside from the niggle over the smell masking, it seems pretty sound to me.

  2. Lauralee said

    Just a guess but “neutral” is likely “no odor”. I think the idea is to make both doses smell alike.

  3. […] who's talking faculty of 1000 on Smells like teen spiritrpg on Fitter healthierNHY on Fitter healthierstevepog on oh carolina, my spidey senses […]

  4. rpg said

    By the way, the evaluation is now live, and here’s the link (free for 3 months.

  5. […] because of one mistake (albeit a pretty huge one). And as my esteemed colleague RPG has previously noted, many alternative remedies have active ingredients which really do […]

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