Psoriasis & Mental Health: Is There a Genetic Link?

Psoriasis Has Been Linked with a Broad Range of Mental Illnesses, Suggesting Genetics and Biology Could Play a Role

Dan
Dan
May 14, 2019
title image for psoriasis and mental health: picture of person's hand on a tree

Psoriasis has long been linked to an increased risk of depression and anxiety. However, recent studies have also linked it to other mental health conditions, including bipolar disorder, vascular dementia, and schizophrenia. Does the connection run deeper than previously believed?

The Established Link Between Psoriasis & Mental Health Conditions

It is no secret that people living with psoriasis are more likely to live with mental health conditions such as depression and anxiety than the general population. It has been demonstrated time and again in studies performed over the years.

The link is often explained by issues such as the stigma that exists around psoriasis, a lack of understanding on the part of healthcare professionals, and when treatment options fail to control the symptoms.

We took a closer look at these issues in a blog we published last year, which you can read here:

These are clearly very real problems that lead to feelings of loneliness, helplessness, embarrassment, and social isolation, which are naturally precursors to mental health problems.

However, studies that have been published recently have also associated psoriasis with an increased risk of other psychiatric diseases, including bipolar disorder, vascular dementia, and schizophrenia.

While external factors such as stigmatization may help explain the increased risk of depression and anxiety, it is hard to see how they would increase one’s risk of other conditions, such as dementia.

Could it be that underlying genetic and biological factors, as well as psychological and environmental ones, increase one’s risk of both psoriasis and mental health conditions?


Howard Chang & John Redfern shared their stories of living with psoriasis on the MyTherapy blog:


Psoriasis & Other Mental Health Conditions: What do the New Studies Say?

One of the two studies published in a May, 2019 JAMA Dermatology journal was a cohort study performed in Denmark. The authors believe it to be the first to look at the long-term risk of a broad spectrum of adult-onset mental disorders (those other than depression, anxiety, and suicidality) in a large population group of people living with psoriasis.

They compared nearly 14,000 people living with psoriasis to the general population. After a five-year follow-up, 2.6% of people living with psoriasis had developed some form of mental problem, a figure that rose to just under 5% after 10 years.

They found both men and women living with psoriasis to be at a greater risk of a range of disorders, including dementia, bipolar disorder, schizophrenia, obsessive-compulsive disorder, and phobic anxiety disorders, among others.

Both men and women living with psoriasis were more than twice as likely to be diagnosed with bipolar disorder than the general population and around 60% more likely to be diagnosed with schizophrenia.

The other study came from South Korea. It used a similar methodology to compare the risk of depressive episodes, anxiety disorders, somatoform disorders, neurotic disorders, and nonorganic sleep disorders in just under 13,000 people living with psoriasis to that of the general population.

In all cases, the risk was at least double for people living with psoriasis.

Could Psoriasis & Mental Health Disorders Be Genetically and Biologically Linked?

The authors of both studies provide theories regarding possible similarities in the underlying mechanisms of psoriasis and mental health disorders.

In the Danish study, the authors cite evidence that inflammation may play a role in the induction and/or progression of bipolar disorder. Given that psoriasis is an autoimmune disease, and that autoimmune diseases are almost always characterized by inflammation, the theory is that those with a susceptibility to one may be similarly susceptible to the other.

Similarly, they mention evidence that has linked immune dysregulation with psychiatric disorders such as schizophrenia.

The authors of the South Korean study suggest a pro-inflammatory T helper cell (specifically, type TH17) that is associated with psoriasis may also play a role in anxiety disorders and depression.

Both of these theories suggest that, while environmental and psychological factors such as loneliness, isolation, and helplessness certainly contribute to the increased risk of mental health disorders, there may also be underlying genetic and biological factors involved.

There is already evidence to support such a notion. A 2018 study, which analyzed 30 relevant studies containing data on 25 million people, found there to be an link between autoimmune disease – including psoriasis – and psychosis.

Like the studies discussed here, the authors of that study suspect a genetic link.

What Does It All Mean?

Explaining the exact nature of the link between psoriasis and mental health disorders is not yet possible. Although significant progress has been made in understanding the mechanisms of psoriasis, much of what is happening at a molecular level remains a mystery – as is the case for every autoimmune disease.

Similarly, our understanding of the biological bases of mental illnesses – while growing – is still small.

While we may not know the precise nature of the connection between psoriasis and mental illnesses, these studies are the latest pieces of evidence to suggest that genetic and biological factors, as well as environmental and psychological ones, are involved.

For now, what the authors of both studies conclude – as does April W. Armstrong, MD, in an editorial published in the same edition of the journal – is that mental health should be considered in the treatment of psoriasis from the beginning.

“The findings reported herein support the need for an approach when treating individuals with psoriasis that focuses not only on their dermatologic condition, but also on their mental health,” say the authors of the Danish study.

Those words are practically mimicked by their South Korean counterparts: “The present results demonstrate that psoriasis is associated with a higher risk for developing mental health disorders; therefore, dermatologists should play a role in detecting mental health disorders in patients with psoriasis, and in assembling a multidisciplinary team of medical professionals to treat these patients.”

Doing so could help improve the quality of treatment and thus, the quality of life, for countless people living with psoriasis.


Take a look at some of the other posts on the MyTherapy blog:

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