Infection-associated neuropsychiatric disorders: Mechanisms and clinical manifestations of psychosis, behavioral alterations and cognitive dysfunction

Infectious diseases are increasingly recognized as contributors to behavioral change, psychosis, and mental dysfunction. Bacterial, viral, parasitic, and fungal pathogens can induce acute or chronic neuropsychiatric symptoms through mechanisms such as direct CNS invasion, neuroinflammation, immune-mediated processes, neurotransmitter dysregulation, and gut–brain axis perturbations. Clinical manifestations include psychosis, mood disturbances, cognitive impairment, and behavioral dysregulation. This five-year retrospective review of cases integrates clinical evidence and mechanistic pathways. Understanding these links is critical for early recognition, prevention, and management of infection-induced neuropsychiatric disorders.