The neurological and psychiatric manifestations of collagen diseases, especially of SLE and periarteritis nodosa were described. One case of SLE associated with the psychiatric manifestations and choreiform movements was presented. The reports of neurological complications in the patients with SLE in Japan throughout the past 20 years were reviewed, compared with those of other countries. The incidence of neurological and psychiatric manifestations of SLE as high as that of other countries. One case of periarteritis nodosa, whose initial symptom was polyneuritis and multineuritis was also presented, and the neurological and psychiatric manifestations of periarteritis nodosa was discussed.