Psychiatric symptoms in patients with systemic lupus erythematosus and in patients with rheumatoid arthritis were examined and compared using a structured interview covering 179 items of psychopathology. The systemic lupus erythematosus patients were 68 consecutive attenders at three general hospitals. The 36 rheumatoid arthritis patients were chosen from attenders at the same clinics as the systemic lupus erythematosus patients. The major conclusions of this study are a) that structured interviewing is feasible and useful in somatopsychic studies; b) that systemic lupus erythematosus patients have, as reported previously in the literature, a high frequency of psychiatric syndromes including those without organic symptoms; and c) that, consistent with expectations derived from the literature, the group of systemic lupus erythematosus patients showed more psychiatric symptoms than the group of rheumatoid arthritis patients.