Psoriasis is a lifelong inflammatory skin disease characterized by red, itchy, and scaly patches of skin. Those who suffer from this disease are also at increased risk for many major medical disorders, including psoriatic arthritis, a type of arthritis characterized by psoriasis plus inflammation of and around the joints.
Now a new Canadian study published in the Journal of Investigative Dermatology finds that psoriasis patients who develop depression have a 37 percent greater risk of subsequently developing psoriatic arthritis, compared with patients who do not develop depression.
“For many years, the rheumatology and dermatology communities have been trying to understand which patients with psoriasis go on to develop psoriatic arthritis and how we might detect it earlier in the disease course,” said lead researcher Cheryl Barnabe, M.D., M.Sc., 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.
Depression is quite common among psoriasis patients. Based on recent laboratory findings showing that major depressive disorder is associated with increased systemic inflammation, the researchers hypothesized that psoriasis patients who develop depression may be at increased risk of developing psoriatic arthritis.
“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,” commented Scott Patten, M.D., Ph.D., 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.”
The researchers evaluated data from primary care medical records in the United Kingdom to find over 70,000 patients with a new diagnosis of psoriasis. Then they identified the patients who subsequently developed depression and those who developed psoriatic arthritis. Patients were followed for up to 25 years or until they developed psoriatic arthritis.
Their findings show 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.
The research emphasizes the need for physicians who treat patients with psoriasis to actively identify and address depression. This could include rapid, effective treatment of psoriasis and psychosocial management of the cosmetic burden of psoriasis.
The findings also draw into question the biological mechanisms by which depression increases the risk for psoriatic arthritis. These mechanisms may include altered systemic inflammation as a consequence of depression, or even the role of lifestyle behaviors such as physical activity or nutrition, which are typically worsened by depression, and which may place an individual at risk for psoriatic arthritis.
“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,” said Laurie Parsons, M.D., of the Cumming School of Medicine.
“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.”
Source: Elsevier Health Sciences