The Stewart Lab is focused on understanding how genetic/gonadal sex influences brain function and dysfunction in the context of neuropsychiatric disorders. In support of a biological basis for sex differences in the pathogenesis of mental illness, we have identified engrained region-specific, sex-biased mechanisms modulating release, reuptake, and signaling of the neurotransmitter dopamine (DA), which controls multiple complex behaviors including motor control, motivation, reinforcement learning, attention, and cognition. Among the projects ongoing in my lab is the determination of how these sex differences shape the neurophysiological and behavior impacts of genetic variants linked to IDDs including the DA transporter (DAT) Val559 variant, identified in boys with ADHD or ASD diagnoses, as well as the G protein regulators RGS6/GNB5 whose genetic variants have been linked to intellectual disability. Ultimately, the goal of the Stewart lab is work toward biological definitions of psychiatric disorders that recognize the modulatory influence of sex and will allow for effective tailoring of therapeutic interventions.