Yep, I'm assuming that the mind is (at least a partial) reflection of brain/nervous system activity in response to the environment in which it finds itself embedded. Is this the whole story? I'd say we don't know -- but I personally have yet to see any evidence of some part of the mind outside of brain/nervous system activity.
The placebo effect proves nothing IMHO. The mind affects the body and vice versa. For an example of the mind affecting the body go to this page and sit back and watch for 15 seconds as the pictures flip by: http://leighb.com/pix2013/Portugal/R001 ... tugal.html
Did the 3rd picture generate any bodily reaction when you realized what you were look at? Maybe not -- I may only get it because I took the picture. But for sure I get a tightening in my gut when I look at that picture -- and its all in my mind.
Given that the jhanas do arise in correlation with distinct brain states, I want to understand those states. Doing so just might make it easier to teach people how to enter and use these states. As for a jhana pill -- our understanding of how the brain works is far too primitive at this time to do so. You'll just have to use the ol' sittin' on a cushion method to get to the jhanas.