Clinical and electrophysiological effects of cathodal high-definition transcranial direct current stimulation to the right superior temporal sulcus in psychosis spectrum disorders: a pilot proof of concept study

= 6 sham) for 5 days with 2 20-minute sessions per day. Assessments occurred at baseline, 5-day, and 1-month timepoints. Electroencephalography (EEG) was recorded during resting state and an AVI steady state (SSR) paradigm. Given the pilot nature of this study, analyses used an alpha threshold of .10. The active group demonstrated reduced clinician-assessed symptoms at 5-days and 1-month, attenuated AVI at 5-days, enhanced auditory SSR and attenuated alpha power over the rSTS at 1-month, and reduced self-reported symptoms at 5-days. Symptom changes correlated with alpha changes. Biological motion, functioning, mood, and cognition did not significantly change. Findings suggest therapeutic effects and successful target engagement. Results provide preliminary proof-of-concept evidence supporting the initiation of a larger trial in psychotic disorders.