Depression, Psoriasis And Risk Of Psoriatic Arthritis: What's the Connection?

Psoriasis patients who develop depression are at a 37 percent greater risk of developing psoriatic arthritis, compared with psoriasis patients who did not develop depression, according to a new study in the Journal of Investigative Dermatology.

Investigators used The Health Improvement Network (THIN), a primary care medical records database in the United Kingdom, to identify more than 70,000 patients with a new diagnosis of psoriasis. Through follow-up records, they identified individuals who subsequently developed depression and those who developed psoriatic arthritis. Patients were followed for up to 25 years or until they developed psoriatic arthritis.

Statistical analysis showed that patients with psoriasis who developed major depressive disorder were at 37 percent greater risk of subsequently developing psoriatic arthritis compared with patients who did not develop depression, even after accounting for numerous other factors such as age and use of alcohol.

"This study raises important questions on the role of systemic inflammation, which is also elevated in depression, in driving a disease phenotype, which needs to be confirmed in clinical cohorts," concludes lead author Cheryl Barnabe, MD, MSc, of the McCaig Institute for Bone and Joint Health and the O'Brien Institute for Public Health, Cumming School of Medicine, at the University of Calgary, Alberta, Canada.

"There is a tendency to think of depression as a purely 'psychological' or 'emotional' issue, but it also has physical effects and changes in inflammatory and immune markers have been reported in depressed people," says Scott Patten, MD, PhD, the O'Brien Institute for Public Health, Hotchkiss Brain Institute and Mathison Centre for Mental Health Research and Education, Cumming School of Medicine. "Depression may be a risk factor for a variety of chronic conditions and this research is an example of how big data approaches can identify these associations."

Laurie Parsons, MD, of the Cumming School of Medicine, adds: "It is evident to physicians who treat patients with psoriasis, that there is a significant psychological and social burden associated with this disease, which is reflected in an increase in the rates of depression. This study brings us a little closer to understanding the role of chronic inflammation as a systemic player in both the physical and psychological manifestations of psoriasis and underscores the need for closer attention to symptoms of depression in this group of patients."