NPR's Shots has an article discussing the correlation between infections and depression and other mental illness:
Late last year, [associate professor] Turhan Canli published a paper [...] 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.
(Score: 1, Insightful) by Anonymous Coward on Wednesday October 28 2015, @07:29AM
It is so common, you can probably find a correlation with almost anything.
Personally, I think what is rare is the person that is entirely free of mental illness for their entire life. Face it - clinical depression alone manifests in roughly 80% of the population. Add very other form of mental illness (antisocial behaviour disorder - the mainstay of upper management for example) and you can cover much of the remainder of the population.