Subsequent risk of hospitalization for neuropsychiatric disorders in patients with rheumatic diseases: a nationwide study from Sweden.

OBJECTIVE: To analyze the association between rheumatoid arthritis, systemic lupus erythematosus, and ankylosing spondylitis and hospitalization for psychiatric disorders, as well as the association between hospitalization for dementia or delirium and systemic lupus erythematosus, by using a novel, large-scale approach.
DESIGN: Cohort study with follow-up between 1973 and 2004. PARTICIPANTS: The entire Swedish population. MAIN OUTCOME MEASURES: Affective, psychotic, neurotic, and personality disorders as well as dementia and delirium.
RESULTS: Individuals with rheumatic diseases had a higher risk of psychiatric disorders than the general population. Those with systemic lupus erythematosus and ankylosing spondylitis had a higher risk of subsequent psychiatric disorders than did patients with rheumatoid arthritis. The significant standardized incidence ratios for rheumatoid arthritis, systemic lupus erythematosus, and ankylosing spondylitis were 1.45, 2.38, and 1.69, respectively, for men, and 1.36, 2.16, and 1.95, respectively, for women. Differences were also found based on subtypes of the rheumatic disease and the psychiatric disorder, sex, and various follow-up intervals. Systemic lupus erythematosus carried an increased risk of dementia and delirium. Only women with rheumatoid arthritis and systemic lupus erythematosus had an increased risk of psychotic disorders and severe depression.
CONCLUSION: Health care providers who encounter patients with rheumatic diseases should be aware that these patients are more likely to develop neuropsychiatric disorders and that some subgroups seem to be more vulnerable than others.