Psoriasis and Depression: A Strong Connection
The itchy, painful sores of skin psoriasis and psoriatic arthritis are difficult to live with. Doctors and researchers are studying how the burden may be related to the development of psychiatric issues, particularly depression.
For someone living with psoriasis and psoriatic arthritis, the chronic itchy and painful symptoms can bare a psychological toll, oftentimes leading to depression. This can become a viscous cycle, as the depression exacerbates the psoriasis,1,2 and the psoriasis exacerbates the depression and pain.3,4
It may not matter how severe the psoriasis is, though. A team of researchers at New York University found that the risk of developing depression was not significantly different between patients with limited psoriasis versus patients with extensive disease.5
"There is definitely a social/behavioral element that may predispose a patient with psoriasis to depression," said Roger S. Ho, MD, MS, MPH, author of the study. Psoriasis is a visible disease, after all. Elevated patches on the skin, also known as plaques, are noticeably red and silvery, which may cause people to assume the condition is contagious or unsightly. These plaques can also be very painful, leading to disability and decreased quality of life, both physically and socially.6
“So, looking at it broadly, it might be the patient’s perception of the social response to their appearance, the stress of anticipating a negative reaction by other people, and the concern of feeling embarrassed or stigmatized based on their appearance that contribute to a great psychiatric burden, driving a psoriasis patient’s depression,” Dr. Ho told Practical Pain Management.
Psoriasis: Strongly Associated with Depression
The study used data from the National Health and Nutritional Exam Survey (NHANES), a survey administered by medical personnel that culls together a large, nationally representative group of people.7
The researchers focused on the most recent data from NHANES, spanning from 2009 through 2012, looking for connections between psoriasis history, depression, and other relevant factors, particularly cardiovascular disease, which has been associated with both conditions. The study was published in JAMA Dermatology.
Out of 12,382 patients in the study, there were 351 (2.8%) people with psoriasis and 968 (7.8%) people with major depression. The researchers found that psoriasis was significantly associated with depression (16.5% vs 8.9%; P < 0.001), as patients were also more likely to suffer depressed mood (as measured by daily functional impairment) due to their depression compared to those without psoriasis. Suicidal ideation was also more significant for psoriasis patients.
Contrary to past research, the severity of psoriasis did not have a major effect on depression risk, suggesting a more uniform risk than previously thought. It also adds credence to the supposition that a patient’s psychiatric issues may be more influenced by the social factors of their appearance, rather than the severity of their condition, as patients may anticipate social stigma or become embarrassed by the way they look.6,8,9
No Additional Risk from Heart Disease
Since a history of heart attack (myocardial infarction, MI) and stroke are often associated with an increased risk for depression, the researchers also looked at the possibility that psoriasis patients with a history of a cardiovascular events (MI and stroke) are even more susceptible to depression.
But that was not the case in this study. Interestingly, the researchers couldn’t find an increased risk for depression in psoriasis patients with histories of cardiovascular events. Even when larger numbers of psoriasis patients with a history of coronary artery disease (CAD) were studied, the results were similarly not significant.
Which Came First—Psoriasis or Depression?
Perhaps the biggest limitation of Dr. Ho's study is that it used data from cross-sectional surveys, which obscured the chronological profile of patients’ psoriasis and depression. In other words, what came first —the psoriasis or the depression?
It is an important question, considering doctors still are learning about how the 2 conditions can trigger each other. According to Dr. Ho, it is more likely that the psoriasis preceded the depression in this cohort, given the nature of the survey questions.
"Establishing a temporal relationship between psoriasis and depression is important as that will help to justify causality, and longitudinal studies are necessary to examine this kind of relationship," Dr. Ho said. However, it does seem that psoriasis and depression can trigger each other independently. Even more significant is the possibility that psoriasis and depression may share some unifying mechanisms.
"I actually firmly believe that there might even be biological factors, such as genetics and mediators of the immune response, that are implicated in the etiology of psoriasis and that might be at play driving the relationship," he noted.
“Psoriasis is an immune-mediated disease caused by a dysregulated immune system. Recent studies have suggested that the immune system might also be responsible for some psychiatric disease. It is plausible that maybe the same mediators of the immune system central to the pathogenesis of psoriasis might also play a role in the development of major depression.” Dr. Ho said he is looking to fund new longitudinal clinical studies to explore this further.
This study utilized data garnered by the National Health and Nutrition Examination Survey (NHANES), publicly available data organized through the Centers for Disease Control and Prevention (CDC). The authors reported no conflicts of interest.