Researchers say people with psoriasis may be at greater risk of depression.
Psoriasis is a systemic, inflammatory, autoimmune disease which mostly affects adults but sometimes also children.
The Centers for Disease Control and Prevention (CDC) describe psoriasis as causing patches of thick, red skin and silvery scales, usually on the elbows, knees, scalp, lower back, face, palms and soles of feet, but sometimes other places such as fingernails, toenails and mouth.
It happens when that part of the body's own immune system becomes overactive and attacks normal tissues in the body.
People with psoriasis are also at risk of psoriatic arthritis, which occurs in 10-20% of psoriasis patients. It is an inflammatory type of arthritis thought to be related to the underlying problem of psoriasis.
16.5% of psoriasis patients had major depression
A number of studies have linked depression and psoriasis, suggesting that depression can exacerbate or trigger psoriasis, and vice versa. Some researchers have claimed that the level of depression is consistent with the amount of psoriasis, while others have found no link between psoriasis and depression. Clearly more research is needed.
- 7.5 million people in the US are estimated to have psoriasis
- 4 in 5 cases of psoriasis are moderate to mild
- 1 in 5 cases of psoriasis are severe, covering 5% or more of the body.
In the current study, Dr. Roger S. Ho, of the New York University School of Medicine, NY, and co-authors set out to investigate the association between psoriasis and major depression in the US population.
The authors analyzed data for participants in the National Health and Nutrition Examination Survey (NHANES) from 2009 through 2012. Diagnosis of major depression was based on a health questionnaire.
They adjusted for cardiovascular risk because prior research has suggested both depression and psoriasis are associated with cardiovascular disease.
Authors identified 351 (2.8%) cases of psoriasis and 968 (7.8%) cases of major depression among 12,382 US residents.
Of these, 58 (16.5%) met the criteria for a diagnosis of major depression. The average patient questionnaire score was higher among patients with a history of psoriasis than those without, according to the results.
Further analyses suggested the risk of major depression did not depend on the extent of the psoriasis, nor did a history of cardiovascular events affect the risk of major depression for patients with psoriasis.
Minor depression symptoms affect psoriasis patients more severely
However, more patients with psoriasis (23.6%) reported that any symptoms of depression, even minor, caused daily functional impairment, compared with patients without psoriasis (15.4%).
The researchers speculate that the psychiatric burden of psoriasis may be related to how patients see the social response to their appearance, rather than objective disease severity.
They cite a separate study of 204 patients attending a psoriasis specialty clinic, who stated that their quality of life was hampered due to the stress of anticipating a negative reaction by other people. In another study of 100 patients, the majority reported that the most challenging aspect of the disease was embarrassment about their appearance.
The study concluded that psoriasis is associated with the risk of major depression, although the risk appears to be unrelated to the severity of the disorder.
Limitations to the study include the use cross-sectional data, making it unclear which came first, the depression or the psoriasis.
The authors conclude:
"Our study supports that all patients with psoriasis, regardless of severity, are at risk for depressive symptoms and may benefit from depression screening."
Medical News Today have previously reported on another study suggesting a link between high blood pressure and psoriasis.