Table 1.

Characteristics of the Included tDCS Studies.

Study	Diagnosis	Sample size (active/sham)	Montage (anode/cathode)	Intensity (mA)	Duration (min)	No. of sessions	Evaluation	Outcomes	Results
Rassovsky et al21	Schizophrenia	37/37	F3/Fp2	2	20	2	Online	MSCEIT, TASIT, EIT, EAT	No significant effect
Brennan et al25	Depression	17/17	F3/contralateral supraorbital area	1.5	30	1	Online	ERT	Significant effects in emotion recognition
Rassovsky et al22	Schizophrenia	12/12	Fp1/Fp2	2	20	1	Online	MSCEIT, TASIT, PONS, FEIT	Significant effects in emotion recognition

Abbreviations: MSCEIT, Mayer–Salovey–Caruso emotional intelligence test; TASIT, the awareness of social inference test; EIT, emotion identification test; EAT, empathic accuracy task; ERT, emotion recognition task; PONS, profile of nonverbal sensitivity; FEIT, facial emotion identification test.

Each study^21,22,25 used the same parameters among active and sham groups. “Significant effects in emotion recognition” meant that stimulation enhanced the ability to identify facial emotion based on photographs or videos.^22,25