Efficacy of Adjunctive High-Frequency Deep Transcranial Magnetic Stimulation for Improving Negative Symptoms in...

Negative symptoms of schizophrenia are disabling and respond inadequately to antipsychotic treatment. Hypofunctioning of cortical areas such as anterior cingulate cortex and medial prefrontal cortex has been implicated in negative symptoms. Repetitive transcranial magnetic stimulation is efficacious for the negative symptoms. Deep transcranial magnetic stimulation (dTMS) has the benefits of repetitive transcranial magnetic stimulation with the advantage of stimulating deeper brain targets.

The aim of the study was to explore the efficacy of high-frequency dTMS for improving negative symptoms in schizophrenia.

This was a sham-controlled, rater, and subject-blinded study. Forty-six patients were randomly assigned into active and sham groups. Ten sessions of high-frequency dTMS at 10 Hz were given at 100% of resting motor threshold using H7 coil over 2 weeks. The Positive and Negative Syndrome Scale, Scale for Assessment of Negative Symptoms, and Clinical Global Impressions were assessed at baseline, at 2 weeks, and at 4 weeks after completion of dTMS.

Forty-three patients completed the study. Although both active and sham groups shown improvement over the time, active dTMS group showed significant improvement in negative symptoms as indicated by significant improvement in the Scale for Assessment of Negative Symptoms score as compared to sham dTMS group ( P  = 0.003, η 2  = 0.158), further substantiated by improvement in negative subscale of Positive and Negative Syndrome Scale ( P  = 0.044, η 2  = 0.079).

Findings from our study suggest that adjunctive high-frequency dTMS significantly improves negative symptoms and severity of illness among patients with schizophrenia. Future studies with larger sample sizes will add our knowledge in the beneficial effects of this newer modality of noninvasive brain stimulation.