Comparisons between Psychiatric Symptoms of Patients with Anti-NMDAR Encephalitis and New-Onset Psychiatric Patients

Abstract

Background: Anti-N-methyl-<smlcap>D</smlcap>-aspartate receptor (NMDAR) encephalitis is a potentially lethal autoimmune disease. Early diagnosis and immunotherapy can improve prognosis; however, early prominent psychiatric symptoms have led to misdiagnosis in numerous cases, delaying diagnosis and treatment. This study aimed to explore the clinical features and psychiatric symptoms of anti-NMDAR encephalitis and the association between antibody titers and psychiatric symptoms. Methods: In this retrospective study, 43 patients with anti-NMDAR encephalitis and 70 new-onset psychiatric patients were enrolled. Psychiatric symptoms were assessed by trained psychiatrists using the Positive and Negative Syndrome Scale. Results: There were significant differences in psychiatric symptoms between the antibody-positive and antibody-negative groups. The item scores for poor rapport (p < 0.01), difficulty in abstract thinking (p < 0.01), lack of spontaneity and flow of conversation (p < 0.01), unusual thought content (p < 0.01), and disorientation (p < 0.01) were significantly higher in the antibody-positive group, while the item scores for delusions (p < 0.01) were significantly higher in the antibody-negative group. These differences all remained significant after Holm-Bonferroni correction. In the antibody-positive group, scores for each item, subscale, and factor increased with increases in antibody titer, particularly for delusions (p < 0.05) and hallucinatory behavior (p < 0.01). Thereafter, only hallucinatory behavior remained significant. Conclusions: Patients with anti-NMDAR encephalitis with initial psychiatric symptoms may have the following characteristics: poor rapport, difficulty in abstract thinking, lack of spontaneity and flow of conversation, unusual thought content, and disorientation. Furthermore, antibody titer may be associated with psychiatric symptom severity, especially in hallucinatory behavior.