1 would also anticipate finding no less than an innate (i.e. not caused immediately because of the drug but e.g. by the anticipation to it) dopamine response to opioid administration in opioid addicts. Alas, although just one is located in animal models (and It can be less than for psychostimulants), https://remingtonshths.onesmablog.com/the-fact-about-4-cmc-that-no-one-is-suggesting-80447263