Dr McCarthy's research career is focused on translational neuroscience and genetics, with an emphasis on Major Depressive Disorder (MDD), and Bipolar Disorder (BD). He is specifically interested in establishing the functional significance of genetic variants associated with BD that have been identified through genomic approaches, especially those identified within the circadian clock system ("clock genes"). The circadian clock gene circuitry is particularly well described and corresponds to well-established animal models and behavioral phenotypes, making this system particularly tractable as a platform for research in psychiatric genetics. Similarly, lithium response is associated with behavioral changes, biochemical processes and gene expression signatures that in many instances are more reliably measured than phenotypes associated with BD itself. Hence, by focusing on the intersection of these, Dr McCarthy hopes to establish more specifically the molecular mechanisms underlying mood disorders like BD.