Research links psoriasis, depression

The following information was provided by board-certified dermatologist Roger S. Ho, MD, MPH, FAAD, assistant professor of dermatology, The Ronald O. Perelman Department of Dermatology, NYU School of Medicine/Langone Medical Center, New York.

What Is Psoriasis?

Psoriasis is a chronic inflammatory disease that typically involves the skin and joints. The majority of people diagnosed with the condition have plaque psoriasis, characterized by red, raised patches of skin covered with silvery-white scales. These raised patches, also known as plaques, usually appear on the scalp, elbows, knees, lower back, hands and feet.

Psoriasis is associated with a number of other medical conditions, including diabetes, cardiovascular disease and depression. Dr. Ho has seen the latter condition firsthand in his patients, starting with one who had severe psoriasis and a clear case of depression. "After treating that patient," he says, "the more I looked, the more I saw depression symptoms in my other patients with psoriasis."

Using data from the National Health and Nutrition Examination Survey, Dr. Ho and his colleagues studied cases of psoriasis and depression in a pool of 12,382 adult patients. About 16.5 percent of the psoriasis patients studied met the criteria for major depression, and the odds of having major depression were doubled among psoriasis patients. The association between the two conditions remained significant even when researchers adjusted for other risk factors, including age, gender, race, body mass index, physical activity, history of alcohol use and smoking, and history of other conditions like myocardial infarction, stroke and diabetes mellitus.

Dr. Ho believes the connection between psoriasis and depression may be linked to the public's stigmatization of psoriasis. The condition is highly visible on the skin, especially in the summer months when more skin is exposed, he says, and those who are unfamiliar with the disease may react unfavorably to people who have it. "The public should know that psoriasis is not contagious, so there is no need to act differently around psoriasis patients than you would around anyone else," Dr. Ho says.

Dr. Ho initially expected that patients' likelihood of depression would be linked to the severity of their psoriasis, but his research indicated that this is not the case. "It seems that it really depends on the patients' view of themselves, rather than the extent of their psoriasis," he says.

Although Dr. Ho's research indicates an association between psoriasis and depression, it does not prove that one causes the other. In order to learn more about the connection between these two conditions, he says, researchers will need to further investigate the nature of that connection and the science behind it. "There may be some biologic or genetic factors in play that we are not aware of yet," he says.

In the meantime, Dr. Ho says psoriasis patients should be aware of their depression risk and consult a doctor immediately if they experience any depression symptoms. He also encourages psoriasis patients to follow the treatment plan prescribed by their dermatologist, as improving their psoriasis symptoms may help alleviate their depression symptoms or prevent the future development of depression. The family and friends of psoriasis patients also should be aware of the condition's connection with depression, Dr. Ho says, as they can help recognize depression symptoms and encourage proper treatment.

"Psoriasis has far-reaching implications for patients' physical and mental health, and that can include an increased risk of depression," Dr. Ho says. "I encourage all psoriasis patients to see a board-certified dermatologist for treatment, which may help improve their quality of life."