Study: "Effect of anti-inflammatory treatment on depressive symptom severity and anhedonia in depressed individuals with elevated inflammation: Systematic review and meta-analysis of randomized controlled trials."
Depression has been traditionally treated globally as a disorder of brain chemistry. But what if the immune system is pulling more strings than we ever realized?
A new University of Michigan and Harvard University systematic review and meta-analysis finds that anti-inflammatory treatments not only reduce depressive symptoms, but also anhedonia-the inability to feel pleasure-in people with both depression and high levels of inflammation.
"This is an important finding that has the potential to make the emerging field of immunopsychiatry more relevant," said the study's co-first author Annelise Madison, assistant professor of clinical psychology and affiliate member in the U-M Eisenberg Family Depression Center.
Immunopsychiatry explores how the immune system and mental health are connected.
The federally funded research, published in the American Journal of Psychiatry, could open doors for personalized treatments, as well as help people who haven't found relief from standard antidepressant therapies, the researchers say.
The systematic review included 19 studies, but the meta-analysis included 14.
Researchers reviewed 19 clinical trials where people with depression and high inflammation were treated with various anti-inflammatory drugs against placebos lasting up to 12 weeks. The anti-inflammatory treatments eased both depression and loss of pleasure in people with high levels of inflammation. The findings also showed no increase in serious side effects.
Regarding the possibility of new anti-inflammatory drugs being developed for depression, she said their use in psychiatry is off-label because the FDA has not approved them to treat depression.
Overall, this meta-analysis, according to Madison, may help to explain why there were prior mixed findings in terms of anti-inflammatory treatment efficacy for depression.
"That is, without focusing on the inflammatory phenotype when recruiting participants, the trial may fail to find effects among a heterogeneous depression sample," she said.
The researchers included co-first author Naoise Mac Giollabhui, Melis Lydston, and Richard Liu of Harvard Medical School; Emma Quang of Harvard University; and Andrew Miller of Emory University.
The work was supported by National Institute for Mental Health grants K23MH132893, R01 MH115905, R01 MH124899, R21 MH130767; R01MH137793, K24 MH136418, a L.I.F.E. Foundation Research Grant, Harvard University's Mind Brain Behavior Interfaculty Initiative, and Massachusetts's General Hospital Translational Clinical Research Center's Early Career Investigator Award
