Electrode montage for transcranial direct current stimulation governs its effect on symptoms and functionality in schizophrenia

Yuji Yamada; Zui Narita; Takuma Inagawa; Yuma Yokoi; Naotsugu Hirabayashi; Aya Shirama; Kazuki Sueyoshi; Tomiki Sumiyoshi

doi:10.3389/fpsyt.2023.1243859

Electrode montage for transcranial direct current stimulation governs its effect on symptoms and functionality in schizophrenia

Front Psychiatry. 2023 Oct 4:14:1243859. doi: 10.3389/fpsyt.2023.1243859. eCollection 2023.

Authors

Yuji Yamada¹, Zui Narita², Takuma Inagawa¹, Yuma Yokoi³, Naotsugu Hirabayashi¹, Aya Shirama⁴, Kazuki Sueyoshi⁴, Tomiki Sumiyoshi⁴

Affiliations

¹ Department of Psychiatry, National Center Hospital, National Center of Neurology and Psychiatry, Tokyo, Japan.
² Department of Behavioral Medicine, National Institute of Mental Health, National Center of Neurology and Psychiatry, Tokyo, Japan.
³ Department of Educational Promotion, Clinical Research and Education Promotion Division, National Center of Neurology and Psychiatry, Tokyo, Japan.
⁴ Department of Preventive Intervention for Psychiatric Disorders, National Institute of Mental Health, National Center of Neurology and Psychiatry, Tokyo, Japan.

Abstract

Backgrounds: Patients with schizophrenia suffer from cognitive impairment that worsens real-world functional outcomes. We previously reported that multi-session transcranial direct current stimulation (tDCS) delivered to the left dorsolateral prefrontal cortex (DLPFC) improved daily living skills, while stimulation on the left superior temporal sulcus (STS) enhanced performance on a test of social cognition in these patients. To examine the region-dependent influence of tDCS on daily-living skills, neurocognition, and psychotic symptoms, this study compared effects of anodal stimulation targeting either of these two brain areas in patients with schizophrenia.

Methods: Data were collected from open-label, single-arm trials with anodal electrodes placed over the left DLPFC (N = 28) or STS (N = 15). Daily-living skills, neurocognition, and psychotic symptoms were measured with the UCSD performance-based skills assessment-brief (UPSA-B), Brief Assessment of Cognition in Schizophrenia (BACS), and Positive and Negative Syndrome Scale (PANSS), respectively. After baseline evaluation, tDCS (2 mA × 20 min) were delivered two times per day for 5 consecutive days. One month after the final stimulation, clinical assessments were repeated.

Results: Performance on the UPSA-B was significantly improved in patients who received anodal tDCS at the left DLPFC (d = 0.70, p < 0.001), while this effect was absent in patients with anodal electrodes placed on the left STS (d = 0.02, p = 0.939). Significant improvement was also observed for scores on the BACS with anodal tDCS delivered to the DLPFC (d = 0.49, p < 0.001); however, such neurocognitive enhancement was absent when the STS was stimulated (d = 0.05, p = 0.646). Both methods of anodal stimulation showed a significant improvement of General Psychopathology scores on the PANSS (DLPFC, d = 0.50, p = 0.027; STS, d = 0.44, p = 0.001).

Conclusion: These results indicate the importance of selecting brain regions as a target for tDCS according to clinical features of individual patients. Anodal stimulation of the left DLPFC may be advantageous in improving higher level functional outcomes in patients with schizophrenia.

Trial registration: These studies were registered within the University hospital Medical Information Network Clinical Trials Registry [(24), UMIN000015953], and the Japan Registry of Clinical Trials [(28), jRCTs032180026].

Keywords: cognition; functional capacity; neuromodulation; schizophrenia; transcranial direct current stimulation (tDCS).

Grants and funding

This work was partially supported by the Japan Society for the Promotion of Science KAKENHI grant no. 20 K16635 to YYa, as well as JSPS KAKENHI grant no. 20H03610, Intramural Research Grants for Neurological and Psychiatric Disorders of NCNP (3-1, 5-3), and Japan Health Research Promotion Bureau Grants (2021-B-01) to TS.