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Biography

Dr. McCarthy earned a B.S. in Biochemistry and Psychology from the University of New Mexico, before completing his doctoral training in medicine and neuroscience at Ohio State University. Dr. McCarthy developed an interest in Bipolar Disorder during his psychiatry residency at UCSD (2005-2009), and subsequently completed a post-doctoral research fellowship in the molecular biology of mood disorders and chronobiology at UCSD. Dr McCarthy joined the UCSD faculty in 2011. He is presently sees patients in the VA San Diego mood-sleep clinic, is the principle investigator on funded basic and clinical research projects in Bipolar Disorder. He is the field editor for neurobiology for Acta Psychiatrica Scandinavica, and a member of the UCSD Clinical Translation Research Institute (CTRI), and Center for Circadian Biology (CCB).

Research Interests

Due to regular intervals of light and dark caused by the Earth’s rotation around the sun, circadian clock genes have been selected through evolution to assist living organisms (including humans) in dealing with changes in temperature, food availability and social interaction. These genes have been shown to govern not only sleep wake behaviors, but also the brain’s reward and motivation systems. For these reasons, clock genes have been implicated in mood disorders such as bipolar disorder and major depression, and also substances abuse disorders like alcoholism. Clinically, the potential for clock gene influence is reinforced by features of these illnesses in which the commonly encountered alterations in sleep wake cycles, appetite, and other rhythmic behaviors are responsive to light availability and/or season. Similarly, lithium, a medication for treating mood disorders, has effects on rhythmic daily behaviors and affects the expression of several clock genes.

In the laboratory, we are using cell lines and DNA from psychiatric patients to examine circadian clock genes. We measure clock gene expression using bioluminescent reporter assays to determine if their rhythms are disturbed relative to cells from unaffected subjects, or if the expression rhythms respond differentially to conditions like lithium treatment or stress. We also examine genetic variants in candidate clock genes to determine if these are associated with clinical features of mood disorders such as lithium response. Where possible, we link associated genetic variants to functional differences in gene regulation.

Clinical Focus

I treat veterans suffering from disturbances in mood where bipolar disorder is considered as likely in the differential diagnosis. Therefore, many of my patients have bipolar disorder, but others may be diagnosed with major depression, personality disorders or psychotic disorders like schizophrenia. Many patients have multiple diagnoses, including post-traumatic stress disorder and substance use disorders. In some cases, I use pharmacogenetic tools or collect genetic samples in hopes of establishing biological predictors of medication response in the future.