DSM-III-R criteria applied in the evaluation of 88 systemic lupus erythematosus patients revealed a point prevalence rate of 18.2% for psychiatric disorders, the most common diagnosis being adjustment disorder (11.4%). No patients had disorders compatible with a functional psychosis. Psychiatric morbidity was not associated with increased disease activity, corticosteroid use, brain magnetic resonance imaging abnormalities, or electroencephalogram abnormalities. High scores on a life event scale were associated with psychiatric disorders, suggesting that psychosocial stress is etiologically important. Cognitive testing showed that poor performance on the Stroop Colour-Word Inference Test was associated with psychiatric disorders.