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A randomized controlled trial of sequentially bilateral prefrontal cortex repetitive transcranial magnetic stimulation in the treatment of negative symptoms in schizophrenia

Barr MS, Farzan F, Tran LC, Fitzgerald PB, Daskalakis ZJ.

Background: Repetitive transcranial magnetic stimulation (rTMS) has been investigated for its treatment efficacy for the negative symptoms of schizophrenia. Previous studies have targeted the dorsolateral prefrontal cortex (DLPFC), which is associated with the pathophysiology of this disorder. Several rTMS parameters have been explored in the treatment of negative symptoms and include stimulating the left and bilateral DLPFC at several different frequencies and number of sessions. Results of such studies have been inconsistent, while high-frequency rTMS has shown greatest promise.

Objective/hypothesis: The objective of this study was to evaluate the efficacy of bilateral high-frequency rTMS in the treatment of negative symptoms in schizophrenia. It was hypothesized rTMS would alleviate negative symptoms in schizophrenia.

Methods: Twenty-five patients were enrolled in this double-blind placebo-controlled randomized trial. Bilateral 20 Hz rTMS was MRI-targeted to the DLPFC at 90% RMT administered daily for 4 weeks for a total of 20 treatments. Negative symptoms were assessed with the Scale for the Assessment of Negative Symptoms (SANS), the Positive and Negative symptom scale (PANSS), and controlling for depression as measured with the Calgary Depression Scale (CDS) at baseline, 1, 2, 3, 4, and 2 weeks after the treatment course.

Results: No significant group or time differences were found on negative symptoms or depressive symptoms after rTMS. Bilateral high-frequency rTMS did not alleviate negative symptoms in patients with schizophrenia.

Conclusions: These findings indicate that such symptoms are unresponsive to rTMS treatment or that more optimized parameters are needed to achieve improved therapeutic efficacy.

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