BrainMap: Ramin V. Parsey, MD/PhD; Application of PET and MRI for Studying Depression

Wednesday, January 27, 2016 - 12:00 to 13:00
149 13th Street (Building 149), main second floor seminar room (2204)

Ramin V. Parsey, MD, PhD

Professor and Chair of the Department of Psychiatry, Stony Brook School of Medicine
Director of PET Research

Title: Application of PET and MRI for Studying Depression

Abstract: Major Depressive Disorder (MDD) is a debilitating disorder with unrelenting chronicity and recurrence. Once projected to be the second leading cause of global disease burden by 2020, this was true by 2013. Meta-analyses suggest that antidepressants only bring about 30% remission rates. This may be attributed to the fact that despite the availability of various pharmacological, psychotherapeutic, and brain stimulation interventions, we still lack the tools to predict treatment response and remission. The emergence of technology such as Positron Emission Tomography (PET) and Magnetic Resonance Imaging (MRI) provides the opportunity to develop models of pathologies and treatments and to probe anatomical and molecular pathways in vivo. Specifically, our group has used PET to quantify serotonin 1A (5-HT1A) receptors in vivo for over a decade. Previously, we have shown that 5-HT1A receptor binding potential is elevated in current and remitted MDD patients. Both acute and chronic treatments with antidepressants reduce 5-HT1A levels.  Further, amongst MDD patients, we have shown that higher baseline 5-HT1A receptors predicted remission to the selective serotonin reuptake inhibitor, escitalopram. This suggests that specific baseline characteristics may aid in the individualized treatment plan that is shown to be effective. Currently, we are bringing together for the first time two major theories of how antidepressants work; the 5-HT1A receptor hypothesis and adult hippocampal neurogenesis, both highly implicated in depression. We propose that the decreases in 5-HT1A receptor binding ultimately increase volume in the dentate gyrus, key region of adult hippocampal neurogenesis, and this will alleviate depressive symptoms. Utilization of both key clinical and biological parameters will lead to better treatment development to help clinicians match appropriate treatments that are personalized and effective for individual patients.