- Depression is common among patients with psoriasis.
- Patients with psoriasis who develop depression were at a greater risk of subsequently developing psoriatic arthritis.
- Major depressive disorder induces many physical effects and changes in inflammatory and immune markers.
Psoriasis patients who were depressed had greater risk of subsequently developing psoriatic arthritis, compared with psoriasis patients who did not develop depression.
The findings were according to a multidisciplinary team of researchers at the University of Calgary, Canada.
Psoriasis is a chronic, inflammatory condition that is associated with significant cosmetic and physical disability. It increases the patients' risk of many major medical disorders.
In United States, around 7.5 million are affected by psoriasis. It affects all age groups but is primarily seen in adults. Around 8.5% of patients with psoriasis have psoriatic arthritis, which is characterized by psoriasis plus inflammation of the joints.
Approximately 80% of those affected with psoriasis have mild to moderate disease, while 20% have moderate to severe psoriasis.
In U.S, the total direct cost associated with psoriasis treatment was estimated to be between $51.7 billion and $63.2 billion in 2013.
"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," explained senior investigator 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.
Depression is also common among patients with psoriasis.
The team of researchers hypothesized that psoriasis patients who develop depression are at increased risk of subsequently developing psoriatic arthritis based on recent findings that major depressive disorder is associated with increased systemic inflammation.
Investigators used The Health Improvement Network (THIN), a primary care medical records database in the United Kingdom, and identified over 70,000 patients with a new diagnosis of psoriasis.
Patients were followed for up to 25 years during which they identified those patients developed depression and those who developed psoriatic arthritis.
Analysis showed that depression among patients with psoriasis increased risk of psoriatic arthritis by 37%, compared with non-depressed psoriatic patients. This was after accounting for numerous other factors such as age and use of alcohol.
Various depression-related biological mechanisms like altered systemic inflammation or even the role of lifestyle behaviors such as physical activity or nutrition, which are typically worsened by depression, increases the risk for psoriatic arthritis.
The study highlights the need to identify and address depression among psoriasis patients. This could include rapid, effective treatment of psoriasis and psychosocial management of the cosmetic burden of psoriasis.
"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, 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." Patten added.
Laurie Parsons, MD, of the Cumming School of Medicine, added "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."
"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," concluded Dr Barnabe.
The findings are published in the Journal of Investigative Dermatology.
- Psoriasis - (https://www.aad.org/media/stats/conditions/psoriasis)
- Cheryl Barnabe et al. Journal of Investigative Dermatology; (2017)