Four patients with systemic lupus erythematosus (SLE) are described in whom there were major psychiatric complications. Two of these patients had cerebral lupus with psychiatric manifestations of the disease together with other features of disease activity and responding to treatment with high dose steroids. The first of these had had a ten-year history of recurrent episodes of depression before other features of the disease became evident; in the second patient recurrent psychotic episodes occurred after the onset of typical multi-system disease. The third patient had had a minor cerebro-vascular accident four years before other features of SLE became manifest, and cerebral deterioration later on in her life was probably due to hypertensive cerebro-vascular disease secondary to the renal disease of SLE. The fourth patient, a young man, had had recurrent episodes of depression and aggressive behaviour for several years and committed suicide at the age of 33.