The folk idea that stress makes you ill has a mechanism under it
Chronic stress wears down cortisol's own off-switch and leaves cells less able to answer the hormone. That pattern turns up alongside lupus, rheumatoid arthritis and multiple sclerosis.
What the study found
Autoimmune disease turns up alongside a failing cortisol feedback loop
Cortisol's own off-switch is a feedback loop, and chronic stress wears it down while leaving cells less able to answer the hormone. That combination turns up alongside lupus, rheumatoid arthritis and multiple sclerosis, putting a mechanism under the folk idea that stress makes you ill.
The caveat · Illness may disrupt cortisol instead
This is a narrative review drawing human and animal work together, not new data. And the arrow could run either way: a stress-disrupted cortisol system might raise autoimmune risk, or years of autoimmune illness might be what disrupts the system. Nothing here separates the two.