The aim of this study is to evaluate, through a pilot study with about ten cases, if bilateral ventral capsulotomy by linear accelerator enable modification of obsessive-compulsive symptoms and quality of life in patients with severe and refractory obsessive compulsive disorder (OCD) and also investigate possible adverse effects / complications of the procedure.

About ten patients with severe and refractory OCD will receive bilateral single lesions at the bottom of the anterior limb of the internal capsule by linear accelerator. Prior to the procedure, a detailed clinical and psychiatric evaluation, plus an extensive battery of psychiatric diagnostic tests, severity and progression of OCD, depression / anxiety symptoms, presence of tics, psychosocial impairment, quality of life, familial accommodation and neuropsychological and personality testes will be performed. Furthermore, the patients will be also assessed by serological and neuroimaging tests. The Individuals will be periodically evaluated and followed up for one year. The results of the scores of the rating scales will be analyzed and compared, as well as the profile of adverse events, cognitive or personality changes and improves in clinical tests and neuroimaging studies.

Inclusion Criteria:

1. OCD diagnosis, according to Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) as a major disease entity. If comorbidity with other psychiatric or personality disorders, OCD symptoms dominate the clinical picture and precede other disorders.
2. Duration of OCD symptoms of at least five years.
3. Scores range of the obsessive-compulsive symptoms "Yale-Brown Obsessive-Compulsive Scale" (YBOCS) greater than 26 (or greater than 13, if obsessions or compulsions alone).
4. Fill up the criteria for refractory to prior treatments.
5. Be accepted by the method of "best estimate" for defining the patient is refractory, which consisted of confirmation by at least two specialists obsessive-compulsive disorder that the patient fulfills the criteria for effective refractory to previous treatments.

Exclusion Criteria:

1. History of head trauma or post-traumatic amnesia.
2. Background of systemic or neurological diseases with brain impairment, severe and active.
3. History of current use of substances capable of inducing psychopathological manifestations, or signs of cumulative effects of alcohol or drugs in the central nervous system (such as cortical atrophy), confirmed by neuroimaging.
4. pregnancy or lactation.
5. Refusal to submit to the radiosurgical procedure.
6. Refusal to accept the informed consent form, or participate.
7. History of mental retardation and / or inability to understand the informed consent, confirmed by neuropsychological tests of the initial evaluation.
8. Lack of family or companion with proper capacity of understanding of the informed consent in patients with comorbid major depression or psychosis that could potentially have difficulty performing the appropriate judgment as to participate in the study.