In earlier work, psoriasis has been linked to depression, anxiety and substance abuse. Studies have shown that both depression and psoriasis are associated with cardiovascular disease, which could confound the association between the two.
Dr. Roger S. Ho and colleagues from New York University School of Medicine used data from NHANES 2009–2012 to investigate the relationship between psoriasis and major depression after adjusting for multiple cardiovascular risk factors.
Their study of more than 12,300 patients included 351 (2.8%) with psoriasis and 968 (7.8%) with major depression. Mean Patient Health Questionnaire-9 (PHQ-9) depression scores were significantly higher among patients with psoriasis than among those without the disease (4.54 vs. 3.22, p<0.001).
Major depression was twice as common among patients with psoriasis after adjustment for sex, age, race, body mass index, physical activity, history of smoking, alcohol use, myocardial infarction, stroke and diabetes, the researchers report in JAMA Dermatology, online Sept. 30.
Patients with psoriasis were also 44% more likely to report that any symptoms of depression caused significant daily functional impairment compared with patients without the skin disease. And they tended to report suicidal ideation more often, although this difference fell short of statistical significance.
The prevalence of major depression did not differ significantly between patients with limited psoriasis (18.4%) and patients with extensive psoriasis (23.1%).
“Therefore,” the researchers conclude, “our study supports that all patients with psoriasis, regardless of severity, are at risk for depressive symptoms and may benefit from depression screening.”
Dr. Dafna Gladman, a rheumatologist at the University of Toronto in Canada, told Reuters Health by email, “We have shown that patients with psoriasis and psoriatic arthritis have a higher risk of depression than those with psoriasis without arthritis. It is clear that psoriasis is not just a skin disease; it is a condition which is associated with a number of comorbidities.”
“Unfortunately from a population based study one cannot ascertain the relationship between the severity of the psoriasis and the depression, nor whether patients were treated for either depression or their psoriasis,” Dr. Gladman said.
“We screen all patients for depression by at least asking them whether they have been depressed and whether they are taking medications for depression, and occasionally using a depression questionnaire,” Dr. Gladman said. “I would suggest that family physicians and dermatologists should be alert to the possibility of depression and therefore address this issue with their patients.”