Positron emission tomography (PET; body scans that measure changes in metabolic processes, blood flow, and other processes) scans have shown increased glucose metabolic rates in the brains of OCD patients, which normalize following treatments such as serotonin reuptake inhibitors (SRIs). However, not everyone with OCD sees their symptoms reduced with an SRI course.

This study, led by Drs. Saxena and Brody, evaluated the addition of risperidone (an antipsychotic) to a course of paroxetine (a SRI; brand name “Paxil”) for patients with OCD who do not respond to SRIs alone. The goals of the study were to assess if adding risperidone to a Paxil course would reduce symptoms, to identify symptom patterns and clinical variables behind the response, and to use PET scans to search for cerebral metabolic patterns that correspond to this treatment. The team aimed to give 15 participants 40mg of Paxil a day for 8 weeks, after which they were sorted into two groups — strong responders and poor responders. Poor responders were then given 60mg of Paxil a day for 4 weeks; if they were still classified as poor responders, 2mg of risperidone a day were added to the 60mg of Paxil for 4 more weeks.