A pilot study to investigate the efficacy and tolerability of lesion network guided transcranial electrical stimulation in outpatients with psychosis spectrum illness.

BACKGROUND

Transcranial electrical stimulation (tES) may improve psychosis symptoms, but few investigations have targeted brain regions causally linked to psychosis symptoms. We implemented a novel montage targeting the extrastriate visual cortex (eVC) previously identified by lesion network mapping in the manifestation of visual hallucinations.

OBJECTIVE

To determine if lesion network guided High Definition-tES (HD-tES) to the eVC is safe and efficacious in reducing symptoms related to psychosis.

METHODS

We conducted a single-blind crossover pilot study (NCT04870710) in patients with psychosis spectrum disorders. Participants first received HD-tDCS (direct current), followed by 4 weeks of wash out, then 2 Hz HD-tACS (alternating current). Participants received 5 days of daily (2×20 min) stimulation bilaterally to the eVC. Primary outcomes included the Positive and Negative Syndrome Scale (PANSS), biological motion task, and Event Related Potentials (ERP) from a steady state visual evoked potential (SSVEP) paradigm. Secondary outcomes included the Montgomery-Asperg Depression Rating Scale, Global Assessment of Functioning (GAF), velocity discrimination and visual working memory task, and emotional ERP.

RESULTS

HD-tDCS improved PANSS general psychopathology in the short-term (d=0.47; pfdr=0.03), with long-term improvements in general psychopathology (d=0.62; pfdr=0.05) and GAF (d=-0.56; pfdr=0.04) with HD-tACS. HD-tDCS reduced SSVEP P1 (d=0.25; pfdr=0.005), which correlated with general psychopathology (β = 0.274, t = 3.59, p = 0.04). No significant differences in safety or tolerability measures were identified.

CONCLUSION

Lesion network guided HD-tES to the eVC is a safe, efficacious, and promising approach for reducing general psychopathology via changes in neuroplasticity. These results highlight the need for larger clinical trials implementing novel targeting methodologies for the treatments of psychosis.