Autoimmune encephalitis and psychiatric disorders.

Autoimmune encephalitis (AE) refers to a rare, newly described, group of diseases associated with specific circulating autoantibodies directed against neuronal proteins used as biomarkers of the disease. Characterization of the associated autoantibodies present in the patients' cerebrospinal fluid (CSF) and/or sera can differentiate the various AE subgroups, which have specific clinical presentations and prognoses, and is therefore essential for proposing appropriate treatments. As psychiatric symptoms may predominate at the onset or over the course of these diseases, the diagnosis is frequently delayed. Yet, patients' prognoses depend on the speed with which the disease is detected, identified and managed. A wide range of neuropsychiatric symptoms is observed according to the patient's AE subgroup, and some are highly suggestive of an immune origin and should be recognized as such by physicians. Because the presence of pronounced psychiatric symptoms drives patients to psychiatric institutions, which can hinder the diagnosis, physicians need to be aware of AE and propose the detection of autoantibodies as early as possible to provide optimal medical care to such patients. In fact, the description of AE subgroups over the past decade has allowed the present overview of their incidence in psychiatric diseases and some general guidelines for the management of these patients.