Priming does not enhance the efficacy of 1 Hertz repetitive transcranial magnetic stimulation for the treatment of auditory verbal hallucinations: results of a randomized controlled study.

Background: Low-frequency repetitive transcranial magnetic stimulation (rTMS) applied to the left temporoparietal area (TP) has been investigated as a treatment method for auditory verbal hallucinations (AVH) yielding inconsistent results. In vitro studies have indicated that the effects of low-frequency rTMS can be enhanced by a brief pretreatment phase consisting of high-frequency rTMS (i.e., priming rTMS).

Objective: The aim of this single-blind, randomized controlled study was to investigate whether the effects of rTMS on AVH can be enhanced with priming rTMS.

Methods: Twenty-three patients with medication-resistant AVH were randomized over two groups: one receiving low-frequency rTMS preceded by 5 minutes of 6 Hertz rTMS; and another receiving low-frequency rTMS without priming. Both treatments were directed at the left TP. The total duration of stimulation was equal in the two groups, namely, 15 sessions of 20 minutes each. The severity of AVH and other psychotic features were measured with the aid of the Auditory Hallucination Rating Scale (AHRS), the Positive and Negative Syndrome Scale (PANSS) and the Psychotic Symptom Rating Scales (PSYRATS).

Results: The severity of AVH and other psychotic symptoms in the group with priming was not significantly lower after 3 weeks of treatment in comparison to baseline. The group treated with standard rTMS showed a trend toward improvement after 3 weeks of treatment. No significant differences were observed on any of the rating scales between the group with and without priming.

Conclusions: This study does not provide evidence that priming rTMS is an effective treatment for AVH.