In the late 1980s, oncologists began treating cancer patients with pro-inflammatory cytokines called interferon alpha (IFNɑ) and tumor necrosis factor-alpha (TNFɑ)(24). The oncologists noticed something unexpected. A subset of their patients developed severe depression soon after the cytokines were delivered into their patient’s bloodstream (27).
One could argue that this is a predictable response. After all, they were diagnosed with cancer and were given what could have been toxic amounts of pro-inflammatory cytokines. Wouldn’t that also make you depressed?
Dr. Andrew Miller of Emory University was one of the first psychiatrists to interview an IFN-ɑ-treated patient. He reported in an interview, “I really expected to see somebody under a blanket who’s shivering and shaking and miserable and toxic, and something that we typically see, and something like sepsis, where somebody’s very sick (28).”
Instead, he observed a “woman was very nicely dressed, makeup was on that looked very nice”, not a deathly ill patient.
Although these patients were not depressed before receiving immunotherapy, they now met the clinical definition of depression. This depression can be prevented by giving the cancer patients an antidepressant two weeks before starting the immunotherapy (23).
If delivering pro-inflammatory cytokines into the bloodstream can cause depression then you would predict that patients suffering from chronic inflammatory diseases and infections would be more prone to developing depression.