Prediction of Clinical Response to SSRI Treatment in Bipolar Disorder Using Serotonin 1A Receptor PET Imaging

Bipolar disorder is associated with alterations of chemicals in the brain, including one named serotonin. Treatment of depression in bipolar disorder can be accomplished by increasing serotonin function by medications named selective serotonin reuptake inhibitors (SSRI's). Serotonin signals in the brain occur through receptors in a way that is similar to a lock and key, where serotonin is a key and the receptor is a lock. One important receptor is the serotonin 1A (5-HT1A) receptor. This receptor has been found to be abnormal in bipolar disorder during periods of depression, as measured by a type of brain imaging called positron emission tomography (PET). The amount of brain 5-HT1A receptor measured by imaging has also been associated with how well depressed patients with major depressive disorder respond to an SSRI medication. This project will measure the 5-HT1A receptors in bipolar depressed individuals using PET with the radiotracer \[11C\]-CUMI-101 and will evaluate the ability of this brain imaging signal to predict how patients respond to SSRI treatment when added to a mood stabilizer.