Patients with systemic lupus erythematosus (SLE) suffer from a number of neuropsychiatric (NP) symptoms throughout their disease affecting them both physically and psychologically. We review herein the nomenclature and case definitions for neuropsychiatric lupus syndromes proposed by the American College of Rheumatology in 1999. We emphasize cognitive dysfunction and discuss etiological hypotheses, especially those related to the presence of antineuronal autoantibodies.