School of Medicine


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  • Sean J. O'Sullivan

    Sean J. O'Sullivan

    Postdoctoral Scholar, Psychiatry

    BioDr. Sean J. O’Sullivan is an MD/PhD postdoctoral scholar from Philadelphia. His PhD in neuroscience from Thomas Jefferson University focused on the molecular mechanisms of alcohol and opioid withdrawal.

    Specifically, he took a systems neuroscience approach to understand the role of the gut microbiome in influencing the negative physical and emotional states that characterize alcohol and opioid withdrawal syndromes.

    This work led to the generation of a novel hypothesis—interoceptive neuroinflammatory signaling involving gut dysbiosis and peripheral network decompensation secondary to abstinence in the context of allostasis drives neuroinflammation in the nucleus tractus solitarius (NTS) and amygdala during alcohol and opioid withdrawal which increases the severity of the withdrawal symptoms. He further conjectures that this interoceptive signaling constitutes an antireward pathway that motivates substance dependence via negative reinforcement.

    He also investigated neuronal subphenotypes in the suprachiasmatic nucleus which is the principle circadian brain region. He further investigated how circadian rhythms affect gene expression in the NTS and amygdala.

    In the Stanford Brain Stimulation Lab, Dr. O’Sullivan is part of the inpatient treatment team that is applying an accelerated transcranial magnetic stimulation (TMS) protocol (Stanford Accelerated Intelligent Neuromodulation Therapy [SAINT]) to hospitalized psychiatric patients. TMS is not currently available to psychiatric inpatients, and this work aims to make this innovative treatment available to those most in need. He is also leading a study researching the effects of TMS on a peripheral biomarker of depression known as L-acetyl-carnitine. He is in the process of applying for psychiatry residency and plans to integrate brain stimulation into his future clinical practice.