The search for a credible placebo
For far too long the research on chiropractic has had the same issue as research on acupuncture, a reliable placebo. Without a credible placebo, studies become impossible to double-blind and very difficult to single-blind. Often times the controls are pain medication or no treatment at all. Many times the studies would show a clear false positive leading to the assumption that chiropractic is more effective than placebo. However, a study just published in the European Journal of Neurology showed that not only does spinal manipulation not work in the treatment of migraines, it also showed a design which may improve future chiropractic studies.
At a university hospital in Norway, a single-blinded randomized controlled trial was performed. A sample size of 104 patients, while small, is sufficient for preliminary studies utilizing this new sham method. The control group continued with their current treatment, the active group received chiropractic treatment for their migraines, and the placebo group received a new sham treatment consisting of spinal manipulation similar to a chiropractic treatment, but in a completely different area and utilizing different manipulation techniques. The blinding was successful and in an exit poll 80% in both the active and placebo groups believed they had received chiropractic treatment.
In all groups the severity and duration of the migraines was lessened, but that is to be expected as any treatment, even the act of participating in the study generally shows improvements. In the end, all three groups experienced similar improvement.
For the first time, we have solid evidence that chiropractic treatments, at least those for migraines, have no efficacy past placebo. This is obviously a result we had expected to see; although now, the study backs up that assumption. Much like a recent review on acpuncture, it seems as if the sham chiropractic treatment may be as effective as the true treatment. One interesting piece of information surfaced in that adverse effects were significantly more frequent in the chiropractic “active” group.
What does this mean?
Well, it means a few things. It means that spinal manipulation (not just chiropractic, but the manipulation performed by osteopaths and physical therapists) does not show efficacy past placebo in controlled and successfully blinded studies for migraines. It also marks the first occasion where researchers were successfully able to blind cohorts, which will hopefully open the door for further research debunking the most accepted pseudoscience in the world, spinal manipulation.