Researchers found people with psoriasis were twice as likely to meet the criteria for major depression than those without the skin disease.
It is estimated that around 7.5 million people in the US have psoriasis. While it can occur in people of all ages, it most commonly develops between the ages of 15 and 25.
The exact cause of psoriasis is unclear, but researchers believe it may be triggered by the immune system attacking healthy cells - particularly skin cells, causing what is known as plaque psoriasis.
Symptoms of plaque psoriasis include itchy, sore and flakey skin, which most commonly occurs on the elbows, knees, scalp, back, face, palms and feet.
Dr. Roger S. Ho, assistant professor of dermatology at the NYU School of Medicine at the NYU Langone Medical Center in New York, NY, says he has seen first-hand how patients with psoriasis can become depressed. As such, he and his colleagues decided to investigate the association further.
People with psoriasis at twice the risk of depression
The researchers analyzed data from the National Health and Nutrition Examination Survey (NHANES), involving 12,382 adults - some of whom had plaque psoriasis.
- Psoriasis is the most prevalent autoimmune disease in the US
- Around 10-30% of people with psoriasis go on to develop psoriatic arthritis - inflammation of the joints
- Around 60% of people with psoriasis say the condition largely impacts their day-to-day lives.
Around 16.5% of patients with psoriasis met the criteria for major depression, according to the results, and the team calculated that individuals with the skin disease were at twice the risk of depression than those without psoriasis.
The researchers say their results remained even after accounting for other risk factors for depression, including age, race, gender, body mass index (BMI), physical activity, alcohol and tobacco use and history of other medical conditions.
The researchers say they are unable to pinpoint exactly why individuals with psoriasis are at greater risk of depression, but Dr. Ho hypothesizes that it may be down to stigma associated with the skin disease.
He explains that because psoriasis is highly visible on a patient's skin, people who see it may "react unfavorably" toward that individual, though he says this is completely unnecessary.
"The public should know that psoriasis is not contagious," he adds, "so there is no need to act differently around psoriasis patients than you would around anyone else."
Based on their findings, the researchers say patients with psoriasis should consult a doctor if they begin to experience any depressive symptoms. Dr. Ho adds:
"Psoriasis has far-reaching implications for patients' physical and mental health, and that can include an increased risk of depression. I encourage all psoriasis patients to see a board-certified dermatologist for treatment, which may help improve their quality of life."
He also calls for family and friends of patients with psoriasis to be aware of the association between the skin condition and depression, and encourage them to seek treatment if depressive symptoms arise.
Further research is warranted to determine whether there are biological or genetic factors that may raise depression risk for psoriasis patients, according to the team.
In a study published in Molecular & Cellular Proteomics earlier this year, researchers revealed how they identified a group of proteins that they believe play a key role in psoriasis development.