Objective. To examine cognitive and psychological functioning in relation to antiribosomal P protein autoantibodies in patients with systemic lupus erythematosus (SLE) who had no previous history of central nervous system disease (non-CNS SLE).
Methods. Comprehensive neuropsychological and psychological tests were administered to 51 non-CNS SLE patients, 29 rheumatoid arthritis (RA) patients, and 27 healthy controls.
Results. Twenty-nine percent of the non-CNS SLE patients, 31% of the RA patients, and 11% of the control subjects were classified as cognitively impaired. Similar reductions in intelligence, attention, and fluency were detected in the non-CNS SLE and RA patients compared with controls. The non-CNS SLE patients showed a distinct deficit in learning compared with the RA and control groups. Forty-two percent of the non-CNS SLE patients demonstrated psychological distress, compared with 7% of the RA patients and 6% of the controls. In the patient groups, neither cognitive dysfunction nor psychological distress was associated with disease activity or prednisone dosage. Elevated serum levels of autoantibodies to ribosomal P protein were not associated with either psychological or cognitive abnormalities.
Conclusion. These results suggest that certain cognitive deficits in non-CNS SLE patients may not be specific to the immunopathology of SLE. In contrast, it is possible that deficits in learning, as well as psychological distress without major psychiatric pathology, may be subtle manifestations of CNS lupus.