Depression and the risk of psoriatic arthritis

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Psoriasis is a lifelong disease that is associated with significant cosmetic and physical disability and puts patients at increased risk for many major medical disorders. Around 30% of those with psoriasis develop psoriatic arthritis, which is characterised by painful joint inflammation; though it is unclear which patients with psoriasis go on to develop arthritic changes.  This recently published study from Canada, suggests that depression may be a trigger.  

Researchers used The Health Improvement Network (THIN) – a large UK General Practice database - 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% 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.  Exactly why depression may increase the risk for arthritis is not clear, but it may be that depression alters the immune system so as to make the underlying inflammation worse, leading to joint changes.    

What is clear, however, is that doctors caring for patients with psoriasis need to be very aware of the importance of depression and should be prepared to intervene early with appropriate treatment, including anti-depressant medication.  In addition, patients with psoriasis should be encouraged to visit their GP if they are experiencing severe mood changes.  

Prompt treatment of depressive symptoms may help to prevent progression of psoriasis into the arthritic phase of the disease.  

Dr David Ashton MD PhD
28 March 2017

Reference
Lewinson RT et al. Depression Is Associated with an Increased Risk of Psoriatic Arthritis among Patients with Psoriasis: A Population-Based Study. Journal of Investigative Dermatology, 2017