The overall planned study duration per subject is 36 weeks, whereby inclusion is timepoint zero and implantation of DBS will be conducted during the first four study weeks. Patients will then undergo an 8-week open-label active DBS treatment phase followed by a 12-week double blind active or sham treatment and finally a 12-week crossover period with the inverse (active/sham) treatment with at least biweekly study visits. Patients as well as patient handling study psychiatrists will be blinded to active/sham. In case of unbearable aggravation of the symptoms during sham, the sham-period will be shortened to a tolerable length. After maximal 38 weeks all study procedures will be completed, and active DBS treatment will be maintained as long as clinically necessary.
The purpose of this randomized, sham-controlled study is to evaluate the effectiveness of DBS therapy in individuals suffering from severe OCD and to investigate DBS treatment with functional [18F]FDG-Brain-PET.