Psychotic and nonpsychotic mood disorders in autoimmune encephalitis: Diagnostic issues and research implications

Abstract

Recent research on autoimmune disorders suggests additional links between systemic and central nervous system (CNS) pathophysiology, among which the identification of antibody-induced limbic encephalitis provided the strongest evidence for the potential involvement of autoimmunity in the pathogenesis of severe mood and psychotic symptoms. In these illnesses, psychiatric symptoms predominate in the initial phase of the disorder in up to 70% of the cases, and they often lead patients to early psychiatric evaluation. For this reason, it is very important to increase the limited knowledge among psychiatrists about these autoimmune neuropsychiatric diseases, which can mimic psychiatric syndromes, in particular, those typically presented in severe mood disorders and schizophrenia. On the other hand, similarities in clinical presentation suggest that neuroinflammation and systemic immune dysregulation may play a role in the pathophysiology of severe mood and psychotic disorders. A complex interaction between periphery and immune cells of the CNS may result in cellular damage through mechanisms involving excitotoxicity, oxidative stress, and mitochondrial dysfunction. These pathways are possibly shared between comorbid medical disorders and severe mood and psychotic disorders and may reflect common underlying vulnerability.