A drug that eases inflammation may offer new hope for people with difficult-to-treat depression, says a new study. ”Inflammation is the body’s natural response to infection or wound,” says Andrew H. Miller, senior study author and professor of Psychiatry and Behavioural Sciences at Emory University School of Medicine. ”However, when prolonged or excessive, inflammation can damage many parts of the body, including the brain,” says Miller, the journal Archives of General Psychiatry reports.
The study was designed to see whether blocking inflammation would be a useful treatment for either a wide range of people with difficult-to-treat depression or only those with high levels of inflammation, according to an Emory statement. The study employed infliximab, one of the new biologic drugs used to treat autoimmune and inflammatory diseases such as rheumatoid arthritis and inflammatory bowel disease.
A biologic drug copies the effects of substances naturally made by the body’s immune system. In this case, the drug was an antibody that blocks tumour necrosis factor, a key molecule in inflammation that has been shown to be elevated in some depressed individuals, according to an Emory statement. When investigators looked at the results for the group as a whole, no significant differences were found in the improvement of depression symptoms between the drug and placebo (no medication) groups.
However, when the subjects with high inflammation were examined separately, they exhibited a much better response to infliximab than to placebo. Inflammation in this study was measured using a simple blood test that is readily available in most clinics and hospitals and measures C-reactive protein or CRP. The higher the CRP, the higher the inflammation, and the higher the likelihood of responding to the drug.
“This is the first successful application of a biologic therapy to depression,” says Charles L. Raison, who led the study. ”The study opens the door to a host of new approaches that target the immune system to treat psychiatric diseases.”
Raison, formerly at Emory, is now associate professor of psychiatry at the University of Arizona College of Medicine in Tucson.