Could Depression Be Caused By An Infection?

Sometime around 1907, well before the modern randomized clinical trial was routine, American psychiatrist Henry Cotton began removing decaying teeth from his patients in hopes of curing their mental disorders. If that didn’t work, he moved on to more invasive excisions: tonsils, testicles, ovaries and, in some cases, colons.

Cotton was the newly appointed director of the New Jersey State Hospital for the Insane and was acting on a theory proposed by influential Johns Hopkins psychiatrist Adolf Meyer, under whom Cotton had studied, that psychiatric illness is the result of chronic infection. Meyer’s idea was based on observations that patients with high fevers sometimes experience delusions and hallucinations.

Cotton ran with the idea, scalpel in hand.

In 1921 he published a well-received book on the theory called The Defective Delinquent and Insane: the Relation of Focal Infections to Their Causation, Treatment and Prevention. A few years later The New York Times wrote, “eminent physicians and surgeons testified that the New Jersey State Hospital for the Insane was the most progressive institution in the world for the care of the insane, and that the newer method of treating the insane by the removal of focal infection placed the institution in a unique position with respect to hospitals for the mentally ill.” Eventually Cotton opened a hugely successful private practice, catering to the infected molars of Trenton, N.J., high society.

Following his death in 1933, interest in Cotton’s cures waned. His mortality rates hovered at a troubling 45 percent, and in all likelihood his treatments didn’t work. But though his rogue surgeries were dreadfully misguided and disfiguring, a growing body of research suggests that there might be something to his belief that infection — and with it inflammation — is involved in some forms of mental illness.

Symptoms Of Mental And Physical Illness Can Overlap

Late last year, Turhan Canli, an associate professor of psychology and radiology at Stony Brook University, published a paper in the journal Biology of Mood and Anxiety Disorders asserting that depression should be thought of as an infectious disease. “Depressed patients act physically sick,” says Canli. “They’re tired, they lose their appetite, they don’t want to get out of bed.” He notes that while Western medicine practitioners tend to focus on the psychological symptoms of depression, in many non-Western cultures, patients who would qualify for a depression diagnosis report primarily physical symptoms, in part because of the stigmatization of mental illness.

“The idea that depression is caused simply by changes in serotonin is not panning out. We need to think about other possible causes and treatments for psychiatric disorders,” says Canli.

His assertion that depression results from infection might seem far-fetched, or at least premature, but there are some data to bolster his claim.

Harkening back to Adolf Meyer’s early 20th century theory, Canli notes how certain infections of the brain — perhaps most notably Toxoplasma gondii — can result in emotional disturbances that mimic psychiatric conditions. He also notes that numerous pathogens have been associated with mental illnesses, including Borna disease virus, Epstein-Barr and certain strains of herpes, including varicella zoster, the virus that causes chickenpox and shingles. To read more from BRET STETKA, click here.