Potential role for kynurenine pathway in increased COVID-19 mortality of patients with schizophrenia

Schizophrenia (SCZ) is a common psychiatric disorder that has complex pathological mechanisms. During the coronavirus disease 2019 (COVID-19) epidemic, patients with SCZ had substantially higher rates of infection with SARS-CoV-2, the virus that causes COVID-19, as well as higher COVID-19 mortality relative to patients without mental disorders. Previous studies suggested that COVID-19 and SCZ both involve the kynurenine metabolic pathway. This article reviews the characteristics of kynurenine metabolism in COVID-19 and SCZ, and considers the possibility that disordered kynurenine metabolism may be one cause of increased infection and COVID-19 mortality rates in the patients with SCZ. Several possible molecular mechanisms that could be involved in disease pathology are discussed.