1 would also expect to find a minimum of an innate (i.e. not triggered immediately through the drug but e.g. through the anticipation to it) dopamine reaction to opioid administration in opioid addicts. Alas, though just one is present in animal versions (and It is lower than for psychostimulants), in https://acetaminophenacetaminophe34073.wikijournalist.com/107980/the_definitive_guide_to_pmk_dortmund