Clinical assessment After a screening visit, the patients fulfilling the inclusion criteria will be assessed before entry the study with a comprehensive clinical interview (age, sex, education, OCD onset, OCD subtype, duration of the illness, history of past or current TICs, previews pharmacological and psychotherapeutic treatments, treatment resistance, lifetime comorbidities) and a psychometric assessment including the following tools: The SCID-5 CV (Structured Clinical Interview for DSM-5 Disorders—Clinician Version), the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS), the Y-BOCS-SC (symptoms checklist) (Goodman et al., 1989a,b), the Hamilton Anxiety rating Scale (HAM-A) (Hamilton, 1959), the Hamilton Depression Rating Scale (HAM-D-17 itemes) (Hamilton, 1967) and the Clinical Global Impression Scale (CGI) (Guy, 2000).