Psychiatric manifestations of encephalitis

Encephalitis is a serious and potentially life-threatening condition of infectious or autoimmune cause. We aim to characterize the frequency and clinical spectrum of presenting psychiatric symptoms in encephalitis in order to inform earlier recognition and initiation of treatment.

This was a retrospective study of adult patients who met the 2013 International Encephalitis Consortium (IEC) and/or 2016 Graus criteria between February 2005 and February 2023. The study included two hospital systems in Houston, Texas, and Baltimore, Maryland and included a total of 642 patients. Psychiatric manifestations were grouped into five high-level categories: behavior, psychosis, mood, sleep disturbances, and catatonia.

In our cohort of 642 patients, 318 (49.6%) had psychiatric symptoms at the time of initial presentation, including 78.2% with autoimmune etiologies and 35.2% with viral etiologies (P < 0.001). Those with psychiatric symptoms were younger (median age 47.5 vs. 51.5; P < 0.001), and more likely to have a history of documented psychiatric disorders, as well as longer lengths of hospital stay, and poorer discharge outcomes. Of patients initially admitted to a psychiatric service (n = 28), most had autoimmune causes, although 3 out of 28 (10.7%) had herpes viral infections; admission to a psychiatric service was associated with substantially longer interval to initiation of antivirals and immunotherapy. Autoimmune and infectious etiologies differed in the spectrum and frequency of psychiatric manifestations.

Psychiatric symptoms are common across etiologies of encephalitis and are associated with longer lengths of hospital stay and worse clinical outcomes. Specific patterns and dimensionality of psychiatric symptoms distinguish autoimmune from infectious causes.