Radiosurgical Treatment for Obsessive-compulsive Disorder

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.