Prevalence of Anti-nuclear and Anti-phospholipid Antibodies in an Egyptian Cohort with Schizophrenia: A Case-control Study

Background: Psychiatric disorders, including schizophrenia, could herald other manifestation( s) of systemic lupus erythematosus (SLE) potentially hindering timely and optimal management. Moreover, schizophrenia is among the described 'extra-criteria' manifestations of anti-phospholipid syndrome (APS). Hence, screening schizophrenia patients for SLE and APS may pose diagnostic and therapeutic implications.

Objectives: Examine schizophrenia patients with no overt connective tissue disease(s) manifestation( s) for clinical and/or serologic evidence of SLE and/or APS.

Methods: The study included 92 schizophrenia patients (61 (66.3%) males) and 100 age- and gender- matched healthy controls. Both groups were tested for anti-nuclear antibodies (ANAs), antidouble stranded deoxyribonucleic acid (anti-dsDNA) antibodies, complement 3 (C3) and C4, and criteria anti-phospholipid antibodies (aPL) (anticardiolipin Immunoglobulin (Ig) G and IgM, antibeta- 2-glycoprotein I IgG and IgM, and lupus anticoagulant (LAC)).

Results: The patients' mean age and disease duration were 28.8 ± 8.1 and 5.7 ± 2.2 years, respectively. The prevalence of ANA positivity, height of titre, and pattern was comparable between patients and controls (p = 0.9, p = 0.8 and p = 0.1, respectively). Anti-dsDNA antibodies and hypocomplementemia were absent in both groups. A significantly higher frequency of positive LAC was observed among patients compared with controls (7.6% vs. 1%, p = 0.02), whereas other aPL were comparable between both groups. None of the patients or controls demonstrated clinically meaningful (medium or high) aPL titres.

Conclusion: In our study, schizophrenia was solely associated with LAC. Thus, in the absence of findings suggestive of SLE or APS, routine screening for both diseases is questionable.