A viewpoint article discusses the apparent benefits from injection of botulinum toxin in patients with chronic migraine, and suggests that they are purely due to a strong placebo response.

The author, a New York neurologist, describes the placebo response and factors that affect it. He notes how the most potent factors inducing a placebo response are present in use of botulinum toxin injection for migraine and points out that in trials, unblinding is frequent due to side effects of the active drug. He discusses the trial programme for the treatment, suggesting that they were impaired because of this.

[Editor's comment: this is a viewpoint article, not a systematic review, nevertheless the author raises interesting points for consideration.]