Table 3. Controlled studies of transcranial direct current stimulation in OCD patients.

Study	N	Age, Years (Range)	Female/ male (N)	Design	Observation (Months)	tDCS Target	Results/Conclusions
D’Urso et al., 2016 [59]	12	39 (range 20-65)	7/5	Patients received initially 10 anodal (n = 6) or cathodal (n = 6) daily for 5 days a week 2 mA/20 min tDCS sessions with the active electrode on the bilateral pre-SMA. If no improvement or no changes: 10 more sessions. In case of symptom worsening after the first 10 sessions: switch to the other polarity for 10 more sessions.	1	Pre-SMA, bilaterally	After 10 sessions: 50% of anodal were switched to cathodal; 100% cathodal continued on the same polarity. Cathodal tDCS correlated with significant mean Y-BOCS score decrease. Anodal tDCS showed no pre-post differences. Cathodal, but not anodal pre-SMA tDCS significantly improved OC symptoms.

tDCS, transcranial Direct Current Stimulation; mA, milliAmpère; OCD, Obsessive-Compulsive Disorder; pre-SMA, pre Supplementary Motor Area; Y-BOCS, Yale-Brown Obsessive Compulsive Scale.