Fatal serotonin syndrome in a patient with Marchiafava–Bignami disease: Combined neurological and psychiatric emergency

•In this report, we present a case with fatal serotonin syndrome happening in a non-alcoholic patient with the chronic form of MBD.•To our knowledge, this case is the first report of fatal serotonin syndrome after starting a small dose of citalopram in an MBD patient.•The present report may indicate that citalopram and other SSRIs should not be used in patients with MBD.•Our case is also among few reported cases in the literature where no cause was identified in a patient with no previous history of alcohol intake. Marchiafava–Bignami disease (MBD) is a rare fatal neurological disorder characterized by demyelination, primary degeneration, and necrosis of the corpus callosum. Although MBD is mostly associated with chronic alcohol consumption and malnutrition, it has been reported in non-alcoholic patients. Serotonin syndrome is a rare but potentially fatal side effect of antidepressants that results from overstimulation of both central and peripheral serotonergic receptors. In this report, we present a case with fatal serotonin syndrome happening in a non-alcoholic patient with the chronic form of MBD. To our knowledge, this case is the first report of fatal serotonin syndrome due to citalopram in an MBD patient. The present report may indicate that citalopram and other SSRIs should not be used in patients with MBD. Our case is also among few reported cases in the literature where no cause was identified in a patient with no previous history of alcohol intake.