A new study suggests a drug used to treat autoimmune disorders and rheumatoid arthritis may help individuals with difficult-to-treat depression.
Researchers say that while inflammation is traditionally associated with the way the body responds to tissue damage, prolonged inflammation can damage many parts of the body, including the brain.
Prior studies have suggested that depressed people with evidence of high inflammation are less likely to respond to traditional treatments for the disorder, including anti-depressant medications and psychotherapy.
Researchers at Emory University designed their study 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.
The study investigated the use of infliximab, a new biologic drug used to treat autoimmune and inflammatory diseases. Each participant was assigned either to infliximab or to a non-active placebo treatment.
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 tumor necrosis factor (TNF), a key molecule in inflammation that has been shown to be elevated in some depressed individuals.
Study participants all had major depression and were moderately resistant to conventional antidepressant treatment.
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 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.
“The prediction of an antidepressant response using a simple blood test is one of the holy grails in psychiatry,” said Andrew H. Miller, M.D., senior author for the study.
“This is especially important because the blood test not only measured what we think is at the root cause of depression in these patients, but also is the target of the drug.”
“This is the first successful application of a biologic therapy to depression,” added Charles L. Raison, M.D., first author of the study.
According to experts, the study proves that new therapeutic approaches targeting the immune system can aid in the treatment of psychiatric diseases.
The study has been published online in the Archives of General Psychiatry.
Sources: Emory University