Brain Imaging Study for OCD using Positron Emission Tomography

Antidepressant medications that target the serotonin system of the brain have long been used in the treatment of OCD and are of significant benefit to approximately 50% of patients. However, whether abnormalities of the serotonin system are a cause of OCD, and how they may contribute, remains quite unclear. Several lines of evidence, from pharmacological studies in patients and from work in mice, suggest that a particular serotonin receptor, the 5HT-1b receptor, may contribute to OCD symptoms.

The Yale OCD Research Clinic is investigating this hypothesis using positron emission tomography (PET), a brain imaging technique that allows visualization of particular neurotransmitter receptors in the brain using very low doses of a radioactive tracer and a special camera. We are examining the receptors both in patients with OCD (on no medications) and in control subjects without OCD, and comparing the two.

This study involves three visits to our clinic. First, subjects will participate in standard screening visit through clinical and medical assessments. Next, participants complete a structural MRI brain scan, which gives a 3-dimensional picture of the brain. The third session is the PET imaging scan itself, which measures activity of particular neurotransmitters in the brain.