Various studies have demonstrated that good treatment responses in Obsessive Compulsive Disorder (OCD) are often obtained in 60 to 80 % of patients, whether employing serotonin reuptake inhibitors or behavior therapy. However, a subgroup of OCD patients are refractory to the classical therapeutic options, even after maximum dosage regimens and sufficiently long treatment follow-ups are devised. Severe psychosocial and occupational impairments are meanwhile observable. These subjects are often referred to stereotactic neurosurgeries. Among the various surgical techniques, a radiosurgical modality (double-shot ventral capsular/ventral striatal - VC/VS gamma capsulotomy, or simply double-shot gamma ventral capsulotomy) has been recently developed. On the other hand, there are no randomized controlled trials of Gamma Knife radiosurgeries in Psychiatry.~The aim of this study is to investigate whether double-shot VC/VS gamma capsulotomy is efficacious and to describe its adverse events/complications profiles, in a double-blind, randomized controlled trial of this radiosurgical technique for the treatment of refractory OCD.~Forty-eight refractory OCD patients will be randomized into two different groups: the first one will receive standard radiosurgery; the second group will be submitted to a false radiosurgical intervention (sham operation). All subjects will be previously assessed by a preliminary clinical/psychiatric interview, as well as by extensive specific instruments regarding psychiatric diagnosis, OCD evolution and severity, anxiety/depression symptoms, tics expression, psychosocial impairment, personality changes, etc. A neuropsychological tests battery will also be employed. All patients will be offered a periodical follow-up, during which assessment scales and neuroimaging exams (magnetic resonance imaging) will be repeated. Patients who had been previously submitted to placebo surgery will be able to undergo real operations after the one-year follow-up period, when blinding is broken. Scores results will be analyzed among the groups, as well as adverse events profiles, cognitive/personality changes, clinical global functioning and neuroimaging findings. Improvements in Yale-Brown Obsessive Compulsive Scale (YBOCS) and Clinical Global Impression (CGI) scores will be taken as the primary treatment response criteria.
Up to 40% of Obsessive-Compulsive Disorder (OCD) patients do not respond to conventional treatments (medications or behavior therapy). For some of them, a neurosurgical treatment can be indicated. Among various surgical techniques, Gamma Knife radiosurgery has the advantage of not requiring the production of burr hole openings in the skull. However, there are no randomized controlled trials of radiosurgical procedures.~The investigators' aim is to investigate whether radiosurgery for the treatment of severe and refractory OCD is efficacious and safe, by a double-blind, randomized controlled trial. Forty-eight refractory OCD patients will be randomized into two different groups: the first one will receive standard radiosurgery; the second group will be submitted to a false radiosurgery (sham operation). Patients who had been previously submitted to sham surgery will be able to undergo real operations after one year of follow-up, when blinding is broken. For a minimum period of one year, patients will be periodically followed-up in terms of psychiatric changes (including OCD symptoms), global functioning, cognitive/personality changes and neuroimaging findings.