Though usually initiated through social reinforcement, self-administration of psychoactive
drugs (SAPD) is soon reinforced pharmacologically through suppression (by each
successive dose) of a homeostatic need generated by successive central counteradaptive
changes (CCCs) that develop unconditionally in response to the initial (receptor site) actions
of such drugs and their" reflex" consequences (signs of drug effects). Temporal contiguity
between pharmacological reinforcement and recurring exteroceptive and interoceptive …