A significant link exists between psoriasis and depression, a study published in the journal Skin Pharmacology and Physiology reported, and suggested that link may also exist for their respective treatments as well, with antidepressants possibly helping to reduce the severity of psoriasis, and psoriasis treatment possibly easing depressive symptoms.
Dr. Hassaan Tohid of the Center for Mind and Brain at the University of California, Davis, and co-authors of the study, “Major Depression and Psoriasis: A Psychodermatological Phenomenon,” searched for relevant literature in various databases to clarify the relationship between the two conditions. They selected 88 articles, and further analyzed them.
The researchers found a significant link between depression and psoriasis, primarily through immune mechanisms related to the actions of inflammatory cytokines, such as tumor necrosis factor-α, interleukin 1 (IL-1), IL-2, IL-10, interferon-γ, IL-1β, prostaglandin E2, C-reactive protein, IL-6, and IL-8.
They also found an association between both conditions and melatonin, or the sleep hormone, with melatonin levels being low in patients with psoriasis or depression and even lower in patients who had both conditions.
Researchers suggested phototherapy — a treatment in which patients are exposed to daylight or certain wavelengths of light — may be effective in both conditions because it can regulate melatonin levels, and can decrease psoriatic inflammation and depressive symptoms that can further worsen psoriasis.
The authors also suggest that both conditions cause each other “due to the possible bidirectional relationship of psoriasis and major depression,” they wrote. “However, if this is the case, then why all depressed patients fail to develop psoriasis and why all psoriatic patients fail to develop depression remains a question unanswered,” they added.
They suggest that future studies analyzing the neuro-immunology of major depression might better uncover this association, and help scientists in exploring the detailed mechanism of how major depression induces psoriasis.
Psoriasis is a long-lasting autoimmune skin disease. It is thought to be a genetic condition triggered by environmental factors such as chronic infections, physical or emotional stress, poor standards of living, and withdrawal of systemic corticosteroid. The condition may worsen with certain factors such as hot water, scratching the psoriasis skin lesions, dry skin, excessive alcohol consumption, smoking, and obesity.