An Investigation of the Possible Inverse Relationships Between the Occurrence of Rheumatoid Arthritis, Osteoarthritis 'and Schizophrenia* S.N. MOHAMED, M.B.,' H. MERSKEY, D.M.,2 S. KAZARIAN, PH.D.3 AND T.F. DISNEY, M.D.4 One hundred and eleven inpatients with schizophrenia and 51 with other psychiatric conditions were compared for the frequency of rheumatoid arthritis, other connec- tive tissue disorders and other physical illness. Evidence both of rheumatoid arthritis and osteoarthritis was sig- nificantly less in the schizophrenia group. Latex Aggluti- nation Tests were positive to the same extent in both groups. One possible explanation of the findings is that they aredue to the reducedfrequency of trauma or stress to the joints in schizophrenic inpatients, many of whom lived in hospital, compared with the controlgroup. Other explanations are also considered. E ven though several studies have investigated the rela- tionship between schizophrenia and rheumatoid arthritis in the same patient, the results so far have been inconclusive. Whereas some.studies suggest the two dis- orders rarely occur together (1-6), other observations and research do not confirm such a negative relationship (7-9). Furthermore, research in this area is replete with methodological inadequacies (6,9). The shortcomings include the absence of clear diagnos- tic criteria, failure in the adequate examination of patients, and the inclusion of female subjects only. Since examination of the relationship between schizophrenia and rheumatoid arthritis may contribute to the under- standing of these conditions, an attempt was made to further explore this issue in the present study. Method Subjects One hundred and eighty newly admitted or chronically hospitalized psychiatric patients between the ages of 36 and *Manuscript received July 1981; revised December 1981. 'Former Unit Director, London Psychiatric Hospital. 2Professor of Psychiatry, University of Western Ontario; Director of Education and Research, London Psychiatric Hospital. lClinical Psychologist, London Psychiatric Hospital. -Asscctate Professor of Medicine, University of Western Ontario; Rheumatic Diseases Unit, Victoria Hospital, Westminster Campus. Address reprint requeststo: Dr. H. Merskey, Director of Educationand Research, London Psychiatric Hospital, 850 Highbury Avenue, P.O. Box 2532, Terminal "A", London, Ontario N6A 4HI. Can. J. Psychiatry Vol. 27, August 1982 381 65 with a diagnosis of functional psychiatric illness at the London Psychiatric Hospital were reviewed. The age range used was chosen in order to increase the chance of rheuma- toid arthritis being present and to increase the likelihood of finding an age-matched control group with functional illness to compare with the schizophrenic patients. Of those who consented to take part, 10 were rejected from the schizo- phrenia group because of diagnostic uncertainty. Two more from that group and 6 of the controls did not complete the assessments. There remained 162 patients (70 male and 92 female). The mean age of the patients was 50.4 years with a range of 36-65. Forty-two were single, 65 married, 11 widowed, 20 separated, 23 divorced and one unknown. The median educational level of the patients was 10years with a range of grade 2 to university degree. The employment status of patients was such that 59 were employed and 113 were unemployed. Procedure The medical records of the patients were thoroughly reviewed for past psychiatric and physical conditions. Each patient was also interviewed individually and received both psychiatric and physical examinations with particular refer- ence to joint or connective tissue disease. A structured form was used to survey for the presence of joint disorders and other physical illness. The ICDA-9 was used for diagnostic purposes. For the identification of rheumatoid arthritis, the diagnostic criteria established by the American Rheumatism Association (10) were adopted. Subsequent to reviews and physical examinations, all cases had a Latex Agglutination Test for Rheumatoid Factor assay and all cases of suspected rheumatoid arthritis, including ·those where an alternative diagnosis of osteoarthritis might be considered, were referred to a Consultant Physician in Rheumatic Diseases (T.F.D.) for an opinion and any additional relevant investigations. The criteria for other arthritides were as follows - prob- able gouty Arthritis: episodes of recurrent acute arthritis of 1-2weeks duration with uricaemia, usually in a typical area such as the big toe; definite or probable Osteoarthritis: a history of pain in the joints, immobility and stiffness of short duration (5-10 minutes), bony thickening and X-ray changes; probable Infectious Arthritis: a history of infection locally affecting the joint with onset of pain and limitation of movement at that time followed by episodic recurrences of pain and limitation of movement.