The finding
This is a randomized, controlled trial studying the efficacy of rTMS in the treatment of excoriation (skin picking disorder or SPD) disorder. The study investigators cited research demonstrating effectiveness of rTMS in OCD spectrum disorders. However, there have been no specific studies examining the use of rTMS in the treatment of SPD. Fifteen patients were either randomized to active or sham rTMS treatment over a 3 week period. Subjects were allowed to continue their current medication regimens which included SSRIs, SNRIs, apytical antipsychotics, and clomipramine. The subjects as well as the physician rater were blinded to the group assignment. The primary outcome measure was the Yale-Brown Obsessive Compulsive Scale modified for Neurotic Excoriation (NeYBOCS, Turkish version). Treatment response was defined as a 35% or greater decrease in scale scores compared to baseline. Outcomes were also measured at 1oneand three month follow up intervals. While there was no significant difference in efficacy between active and sham rTMS treatments, 62.5% of subjects in the active treatment group achieved treatment response vs. only 33.3% in the sham group. Only three of the five patients in the active group who responded to treatment and two in the sham group attended the one month and three month follow up visits. Of the remaining three active treatment subjects, two had worsened symptoms at one month follow up, while the remaining subject maintained symptom improvement up to twi months following the completion of treatment but at month three experienced increased symptoms.  Both sham treatment subjects experienced immediate worsening of their symptoms at the end of the study.

Strengths and Weaknesses
Strengths include randomization and blinding of both subjects and physician raters. However, there were many weaknesses. Primary among them was the very small sample size which does not allow the investigators to make any definitive conclusions regarding the efficacy of rTMS in SPD. The study did not exclude psychiatric comorbidities, and it did not control for the varying medication regimens of the participants. Further, the authors cite that they applied rTMS via anatomic mapping instead of via navigation systems which could account for anatomic variations about the subjects and could have resulted in variable results.

Relevance
While a negative study, the findings suggest that rTMS may be an effective treatment for medication resistant SPD.

Type of study (http://ebm.bmj.com/content/early/2016/06/23/ebmed-2016-110401)
randomized controlled trial