Alteration in Plasma BDNF Level after Repetitive Transcranial Magnetic Stimulation(rTMS) in Treatment-Resistant Schizophrenia: A Pilot Study

ABSTRACT

OBJECTIVES: To assess clinical improvement and change in plasma brain-derived neurotrophic factor(BDNF) level after repetitive transcranial magnetic stimulation(rTMS) in patients with treatment-resistant schizophrenia. METHODS: Seven patients with DSM-IV schizophrenia, who were proven to be treatment-resistant, were treated with 15 sessions of rTMS for three weeks as an adjuvant therapy to antipsychotic treatment. Clinical improvement and change in plasma BDNF level were measured after the treatment period. The symptom severity was assessed with the Positive and Negative Syndrome Scale(PANSS) and the Korean Version of Calgary Depression Scale for Schizophrenia(K-CDSS) at baseline and 7 days after the treatment. Plasma BDNF level was measured by enzyme-linked immunosorbent assay(ELISA) at baseline and 7 days after the treatment. RESULTS: After the rTMS treatment, there was no significant improvement in PANSS total score(Z=-1.693, p=0.090) and no significant change in plasma BDNF was found(Z=-1.183, p=0.237). Negative correlations were found between percentage change in PANSS positive subscale score and duration of illness(rho=-0.991, N=7, p<0.0005, two-tailed), and PANSS negative subscale score at baseline and percentage change in plasma BDNF level(rho=-0.821, N=7, p=0.023, two-tailed). CONCLUSION: This preliminary study suggests that rTMS didn't make a significant change in clinical symptoms nor in plasma BDNF level in treatment-resistant schizophrenia. Percentage change in plasma BDNF, however, might be correlated with treatment resistance in schizophrenic patients. This is a pilot study with a small sample size, therefore, a further study with a larger sample size is needed.