The mean reduction in the PANSS negative symptoms subscale scores (intention-to-treat analysis) in the active transcranial direct current stimulation (tDCS) and sham tDCS treatment groups from baseline to week 12. Scores on the PANSS negative symptoms subscale range from 7 to 26, with higher scores indicating more severe negative symptoms. Treatment with active tDCS was superior to sham tDCS at week 6 (PANSS score point difference, 2.65; 95% CI, 1.51-3.79; P < .001) and at week 12 (PANSS score point difference, 2.35; 95% CI, 1.02-3.67; P < .001). Error bars represent 1 SE.