Dramatic placebo effect of high frequency repetitive TMS in treatment of chronic migraine and medication overuse headache.

Chronic migraine (CM) is often associated with medication overuse headache (MOH). Few small trials have been conducted on Transcranial Magnetic Stimulation for CM treatment, but results are conflicting. Aim of the study was to investigate the effects of high frequency of repetitive Transcranial Magnetic Stimulation (hf-rTMS) in the dorsolateral prefrontal cortex combined with strongly suggesting to avoid medications overuse in patients suffering with CM and MOH. A six-month single-centre perspective randomized double-blinded study was conducted at the Headache Centre of Trieste. Patients suffering with CM and MOH were randomly enrolled in two groups to receive active hf-rTMS in DLPFC or sham hf-rTMS. Headache days (HD), headache hours (HH) and symptomatic drug intake (SDI) were recorded for 30 days before the beginning of stimulation (T0) and during the three following months (T3). Disability (MIDAS score) was evaluated at T0 and at the three-month follow-up visit. The primary outcome was the evaluation of reduction of HD. Reduction of SDI, HH and disability were considered as secondary outcomes. Out of 26 patients enrolled, 14 completed the study, 7 underwent hf-rTMS and 7 sham-TMS. There were no significant differences between groups at T0 in demographic data and headache measures. Mean number of HD, HH, SDI, and MIDAS similarly reduced in the two groups. Our study failed in demonstrating that hf-rTMS with detoxification advice could be better than detoxification advice alone in CM treatment. hf-rTMS carries a high potential of inducing placebo effect and this can be usefully leveraged to enhance patients' coping strategies.