People with rheumatic diseases are more likely to develop severe
psychiatric disorders than the general population is, a study reported in the
May Archives of General Psychiatry has found.
Although previous studies have examined possible links between rheumatic
diseases and psychiatric disorders, this is the first one that has tackled the
subject in an entire country—Sweden.
Kristina Sundquist, M.D., Ph.D., a professor of family medicine at the
Karolinska Institute in Sweden, and coworkers first calculated how many Swedes
between 1973 and 2004, that is, a 31-year span, had been hospitalized for any
one of three rheumatic diseases—ankylosing spondylitis, systemic lupus
erythematosus, or rheumatoid arthritis. They found that 59,646 individuals had
been so hospitalized. Moreover, the bulk of the patients had been hospitalized
for rheumatoid arthritis. The remaining were hospitalized for either
ankylosing spondylitis or lupus in about equal numbers.
They found that of the 59,646 individuals who had been hospitalized for a
rheumatic disease, 1,653 were subsequently hospitalized for a psychiatric
disorder. The researchers then compared the rates of hospitalization for a
psychiatric disorder in their rheumatic-disease population with the rates in
the general Swedish population during the same period, taking some possibly
confounding factors such as age and gender into consideration. They found that
the rates for the rheumatic group were higher than those for the general
population. Overall, the highest rates were found for men and women with
lupus. Their significant age-standardized incidence ratios were 2.38 and 2.16,
Moreover, rheumatic subjects' risk of being hospitalized for a psychiatric
disorder turned out to be influenced not just by their gender but by the type
of rheumatic disease they had. For example, men with lupus, men with
ankylosing spondylitis, and both men and women with rheumatoid arthritis had a
heightened risk of being hospitalized for an affective or personality
disorder. In contrast, women with ankylosing spondylitis had a heightened risk
of being hospitalized only for an affective disorder, and women with lupus had
a heightened risk of being hospitalized for an affective disorder, a
personality disorder, or a psychotic disorder.
Although the study was not able to demonstrate definitively that the
rheumatic diseases in question led to the psychiatric illnesses in question,
Sundquist believes that was the case. She told Psychiatric News,"
I believe that possible pathways behind this causal link are
psychological and immune mechanisms."
Another reason to believe that the rheumatic diseases in question led to
the psychiatric illnesses was the researchers' discovery that the strongest
links between the two emerged when the interval between them was less than a
These findings are largely consistent with those obtained in other
countries, Sundquist and her colleagues pointed out in their study report.
The study was funded by the Swedish Research Council and the Stockholm
An abstract of "Subsequent Risk of Hospitalization for
Neuropsychiatric Disorders in Patients With Rheumatic Diseases" is