Essali N, et al. - Using VigiBase (a World Health Organization global individual case safety report database), researchers determined the prevalence of psychotic symptoms as adverse drug reactions spontaneously-reported by consumers of monoclonal antibodies (mAbs). For individual mAbs, odds of psychosis were calculated, compared to bevacizumab, which does not directly target the immune system. Psychosis was identified as a relatively rare adverse impact of mAb therapy, but variations in risks by specific agents were evident. For psychosis related to monoclonal antibodies, a prevalence of 0.1–0.4% was reported. Increased odds of psychosis were reported in relation to 7 monoclonal antibodies (2 anti-CD25 agents) and decreased odds were reported in relation to 8 monoclonal antibodies (4 anti-TNF-α agents). Sometimes, immune system modulation may cause psychosis development.