Recent studies highlighted the link of schizophrenia risk with genetic variations in complement, which share the same pathogenesis with systemic lupus erythematosus (SLE). However, the coexistence of SLE and schizophrenia were rarely reported. We aimed to explore the autoantibody profiles, complement levels and prevalence of SLE in chronic schizophrenia patients.
A prospective, cross-sectional study was conducted to recruit 481 long-term hospitalized schizophrenia spectrum disorder patients in Yuli hospital, Taiwan. Severity of schizophrenia was assessed by Positive and Negative Syndrome Scale (PANSS). Immunologic tests of autoantibodies and complement levels were measured. Genome-wide association analysis was conducted to compare genetic variants between schizophrenia with SLE and non-SLE schizophrenia.
In total, 47 (9.8%) and 31 (6.4%) participants had positive anti-nuclear antibody (ANA) and anti-double stranded DNA (anti-dsDNA) antibodies, respectively. After rheumatologic exams, 30 (6.2%) patients were diagnosed schizophrenia with SLE, while 32 (6.7%) subjects were classified as schizophrenia with autoimmune features. Schizophrenia patients with SLE had more arthritis, serositis, homogenous ANA pattern, conceptual disorganization in PANSS and increased salivation due to psychotropics compared with their counterparts. ANA titers and complement levels were significantly correlated with PANSS scores and side effect of psychotropics. No significant genetic variation between schizophrenia with SLE and non-SLE schizophrenia were identified.
SLE may coexist in chronic hospitalized schizophrenia. Complement levels could be a potential biomarker in schizophrenia patients. Considering the possible reversibility of psychotic features and adverse effects of antipsychotics, SLE with psychosis should be identified in patients with chronic hospitalized schizophrenia.

Copyright © 2021. Published by Elsevier B.V.