Table 1.
Main findings of studies investigating the clinical interest of transcranial direct current stimulation (tDCS) to decrease symptoms in patients with obsessive-compulsive disorder (OCD).
| Articles | N | Patients Characteristics | Target | Intensity Electrode Size | Duration and Number of Sessions | Main Results |
|---|---|---|---|---|---|---|
| Volpato et al., 2013 [20] | 1 | Age: 35, male | Anode: posterior neck-base Cathode: left DLPFC |
2 mA, 35 cm2 | 20 min, 10 sessions (1/day) | No effect on OC symptoms. Depression score decreased (−34% HDRS); anxiety score decreased (−17%). |
| Type*: 2,3,4 | ||||||
| Previous TTT: SSRI, SNRI, CBT | ||||||
| Mondino et al., 2015 [22] | 1 | Age: 52, female | Anode: right cerebello-occipital (100 cm2) Cathode: left OFC |
2 mA, 35 cm2 | 20 min, 10 sessions (2/day; 2 h between 2 sessions) | YBOCS score decreased (−26%) |
| Type*: 3,4 | ||||||
| Previous TTT: tricyclic, SSRI, SNRI, AP, Lithium, CBT | ||||||
| Hazari et al., 2016 [17] | 1 | Age: 24, male | Anode: SMA Cathode: right OFC |
2 mA, ND | 20 min, 20 sessions (2/day, at least 3 h between 2 sessions) | YBOCS decreased (−80%) during 7 months |
| Type*: 1,2 | ||||||
| Previous TTT: SSRI, ECT | ||||||
| D’Urso et al., 2016 [23] | 1 | Age: 33, female | Anode: Pre-SMA Cathode: right deltoid And then, Reverse montage |
2 mA, 25 cm2 | 20 min, 10 sessions (1/day) | Worsening of symptoms after anodal tDCS. |
| Type*: 3 | ||||||
| Previous TTT: SSRI, BZD, tricyclic, CBT | YBOCS score decreased (−30%) after cathodal tDCS, | |||||
| Alizadeh Goradel et al., 2016 [19] | 1 | Age: 23, female | Anode: right occipital Cathode: left OFC |
2 mA, 25 cm2 | 20 min, 10 sessions (1/day) | YBOCS score decreased (−64%); Depression score decreased (−87%); −100% anxiety |
| Type*: 1 | ||||||
| Previous TTT: SSRI | ||||||
| Palm et al., 2017 [25] | 1 | Age: 31, male | Anode: left DLPFC Cathode: Right DLPFC |
2 mA, 35 cm2 | 30 min, 20 sessions (2/day, 3 h between 2 sessions) | Combined with Sertraline, YBOCS score (−22%), depression (−10%) and anxiety (−21%) decreased |
| Type*: 1,3 | ||||||
| Previous TTT: tricyclic, SSRI, AP, CBT | ||||||
| Narayanaswamy et al., 2015 [21] | 2 | Age: 39, female | Anode: left pre-SMA Cathode: right OFC |
2 mA, 35 cm2 | 20 min, 20 sessions (2/day, at least 3 h between 2 sessions) | Patient 1: YBOCS score decreased (−40%), −52% at day 17 |
| Type*: 1 | ||||||
| Previous TTT: SSRI, exposure | ||||||
| Age: 24, male | Patient 2: YBOCS score decreased (−46.7%) | |||||
| Type*: 1 | ||||||
| Previous TTT: tricyclic, SSRI | ||||||
| Silva et al., 2016 [24] | 2 | Age: 37, male | Anode: right deltoid Cathode: bilateral SMA |
2 mA, 25 cm2 | 30 min, 20 sessions (1/day) | Patient 1: no effect at Week 4, YBOCS score decreased at week 12 (−18%). No changes in anxiety nor depression |
| Type*: 2 | ||||||
| Previous TTT: tricyclic, SSRI, CBT | ||||||
| Age: 31, male | Patient 2: YBOCS score decreased, (−17%) at Week 4; −55% at week 12). 50% improvement in anxiety and depression | |||||
| Type*: 1,3 | ||||||
| Previous TTT: tricyclic, SSRI | ||||||
| Dinn et al., 2016 [18] | 5 | Age: 40.4 (8.4), 4 females, 1 male | Anode: left DLPFC Cathode: right OFC |
2 mA, 35 cm2 | 20 min, 15 sessions (1/day) | Open Label Study |
| Type*: ND | ||||||
| Previous TTT: SSRI, SNRI, AP | OC symptoms decreased (−23%); depression decreased (−30%) | |||||
| Bation et al., 2015 [26] | 8 | Age: 44.2 (13.8), 6 females, 2 males | Anode: right cerebellum Cathode: left OFC |
2 mA, 35 cm2 | 20 min, 10 sessions (2/day, at least 3 h between 2 sessions) | Open Label Study |
| Type*: 1 (n = 5), 3 (n = 3) | ||||||
| Previous TTT: tricyclic, 3 SSRI, AP, CBT | YBOCS score decreased (−24.6%) | |||||
| D’Urso et al., 2016 [28] | 12 | Age: 39.0 (13.1), 7 females, 5 males | Anode midline pre SMA Cathode: right deltoid (n = 6) OR reverse montage |
2 mA, 25 cm2 | 20 min, 10 sessions (1/day) | RCT—10 patients completed the study |
| Type*: 1 (n = 4), 2 (n = 2), 3 (n = 6) |
Cathodal tDCS was significantly more effective than anodal tDCS. In cathodal arm, YBOCS score decreased (−17.5%) after 10 sessions, −20.1% after 20 sessions | |||||
| Previous TTT: at least SSRI, CBT | ||||||
| Najafi et al., 2017 [27] | 42 | Age: 29.1 (10.1), 23 females, 19 males | Anode: parieto-temporo-occipital areas Cathode: right OFC |
2–3 mA, 5.5 cm² | 30 min, 15 sessions (1/day) | Open Label Study |
| YBOCS score decreased (−63.4%) | ||||||
| Type*: ND | ||||||
| Previous TTT: at least 2 SSRI, CBT | Maintenance of the effect at 3 months follow up (−77.6%) |
DLPFC: dorsolateral prefrontal cortex; HDRS: Hamilton Depression Rating Scale; ND: Not Done; OFC: orbitofrontal cortex; (pre) SMA: (pre) supplementary motor area; Y-BOCS: Yale-Brown Obsessive Compulsive Scale. Age: mean (standard deviation) years, TTT: treatment, AP: antipsychotic, SSRI: selective serotonin reuptake inhibitor, SNRI: serotonin–norepinephrine reuptake inhibitor, CBT: cognitive behavioural therapy. Type* 1 = obsessions and checking, 2 = symmetry and ordering, 3 = cleanliness and washing, 4 = hoarding according to Leckman et al. 1997 [30].