Prevalence of neuropsychiatric lupus in psychosis patients with a positive antinuclear antibody.

OBJECTIVES Psychosis is a rare manifestation of Neuropsychiatric Systemic Lupus Erythematosus (NPSLE). Current guidelines do not make a recommendation regarding the use of Antinuclear Antibodies (ANA) testing in the assessment of patients with psychosis. This study was undertaken to determine the prevalence of NPSLE in patients with psychosis who have had positive ANA. METHODS Retrospective review of patients admitted to the mental health service of two metropolitan tertiary referral centres with a diagnosis of psychosis, who had been tested for ANA. A diagnosis of SLE was made when the 2019 ACR/EULAR classification criteria were fulfilled. Attribution of psychosis related events to NPSLE were made according to validated criteria. RESULTS There were 10,205 mental health admissions with diagnoses of psychosis representing 4766 individual patients, 911 (19%) patients were tested for ANA, 135 (15%) of those tests returned a positive result with a titre ≥1:160. The mean follow-up time was 47 ± 26 months. At discharge there were four patients who met 2019 ACR/EULAR criteria for SLE, two of whom met criteria for NPSLE. Both of these patients had other manifestations of SLE. This gave an NPSLE prevalence of 1.5% (2/135) amongst patients with positive ANA, and 0.2% (2/911) amongst all patients who underwent testing for ANA. CONCLUSIONS The prevalence of NPSLE in patients with psychosis and positive ANA was low at 1.5%. The low rate of clinically significant positive results would argue against routine testing for ANA in psychosis patients.