Ha! Endorphins are "endogenous opioid peptides produced by the pituitary and hypothalamus glands that function as the body's natural painkillers and mood regulators".

"They are part of the endogenous opioid system", so either way was talking about literal highs.

The endocannabinoid system (I hope that I have the spelling correct) is a relatively recent discovery (1980s on), and is quite fascinating on how integral to the human body it is