Psychosis as an adverse effect of monoclonal antibody immunotherapy

Immunotherapy is a hot area in schizophrenia research. Monoclonal antibodies (mAbs) target specific immune molecules, and therefore offer an unparalleled opportunity to directly test the hypothesis that immune dysfunction plays a causal role in psychopathology in schizophrenia. Cytokine-based immunotherapy for other disorders has been associated with a range of neuropsychiatric adverse effects, including psychosis. The purpose of the present study was to investigate the prevalence of spontaneously-reported adverse drug reactions of psychotic symptoms for mAbs, and to calculate odds of psychosis for individual mAbs, compared to bevacizumab, which does not directly target the immune system. We searched the publicly available VigiBase, a World Health Organization global individual case safety report database from inception through February 2019 for which a mAb was the suspected agent of an adverse drug reaction (ADR). We investigated 43 different mAbs, comprising 1,298,185 case reports and 2025 psychosis ADRs. For individual mAbs, the prevalence of psychosis ADRs ranged from 0.1 to 0.4%. Seven mAbs were associated with a significantly increased odds of psychosis (OR = 1.42-2.22), including two agents that target CD25. Eight mAbs were associated with a significantly decreased odds of psychosis (OR = 0.28-0.75), including 4 anti-TNF-alpha agents. Our results suggest that psychosis is a relatively rare adverse effect of mAb treatment, but risks vary by specific agents. Findings indicate that modulating the immune system may sometimes lead to the development of psychosis. Ongoing clinical trials of adjunctive mAb immunotherapy in schizophrenia will provide valuable insights into the role of the immune system in psychosis.