To find out if acupuncture was affecting chronic stress, Eshkevari and a team of researchers looked at what happened in a key pathway in dealing with stress for both humans and rats: the hypothalamus-pituitary-adrenal axis (HPA). It’s the same pathway targeted by some anti-anxiety drugs and antidepressants, Eshkevari says, and the HPA is involved in the production of the stress hormone cortisol.