The purpose is to show that bifocal tDCS with an anodal stimulation on the orbitofrontal cortex and cathodic stimulation on supplementary motor areas is an effective treatment for patients with resistant and severe obsessive compulsive disorders.

Patients must present all of the following criteria in order to be eligible:

Inclusion Criteria:

• Meets criteria for obsessive compulsive disorder according to DSM-IV with a "good insight" (BABS),
• Age: Participants will be both males and females, 18-70 years of age included.
• No current depressive and suicidal risks,
• No epileptic pathology,
• Chronic evolution ( Total Y-BOCS>20 ),
• Obsessive compulsive disorder resistant to pharmacology treatment, at least 2 antidepressants (type IRS) or cognitive and comportment therapy since at least one year,
• Stability treatment (antidepressants) for more than 12 weeks without significant improvement,
• Affiliation to a social security system (recipient or assignee),
• Signed written inform consent form.

Exclusion Criteria:

• Female subject who is pregnant, or of child-bearing age, sexually active and not using reliable contraception or who is nursing,
• Patient under curators
• Meets another diagnosis of axe 1 of DSM-IV,
• Current depressive or suicidal risks,
• Patient with a benzodiazepine treatment,
• Patient with any form of metal in the cranium, a pacemaker, skull defects, or skin lesions to the scalp (cuts, abrasions, rash) ,
• Epileptic patient,
• Patient with a medical history of cranial trauma,
• Patient unable to give his or hers informed consent.