Non-pharmacological factors modulate pharmacological action of drugs; environmental conditions shape drug search and self-administration; social stress is a crucial determinant of effects; drug instrumentalization allows highly specific drug use in non-addicts

Non-pharmacological factors that determine drug use and addiction. Serge H. Ahmed e al. Neuroscience & Biobehavioral Reviews, https://doi.org/10.1016/j.neubiorev.2018.08.015

Highlights
•    Non-pharmacological factors modulate pharmacological action of addictive drugs.
•    We review the neurobiological mechanisms of non-pharmacological influences.
•    Environmental conditions shape drug search and self-administration.
•    Social stress is a crucial determinant of drug effects.
•    Drug instrumentalization allows highly specific drug use in non-addicts.
•    Behavioral alternatives shape drug choice and consumption patterns.

Abstract: Based on their pharmacological properties, psychoactive drugs are supposed to take control of the natural reward system to finally drive compulsory drug seeking and consumption. However, psychoactive drugs are not used in an arbitrary way as pure pharmacological reinforcement would suggest, but rather in a highly specific manner depending on non-pharmacological factors. While pharmacological effects of psychoactive drugs are well studied, neurobiological mechanisms of non-pharmacological factors are less well understood. Here we review the emerging neurobiological mechanisms beyond pharmacological reinforcement which determine drug effects and use frequency. Important progress was made on the understanding of how the character of an environment and social stress determine drug self-administration. This is expanded by new evidence on how behavioral alternatives and opportunities for drug instrumentalization generate different patterns of drug choice. Emerging evidence suggests that the neurobiology of non-pharmacological factors strongly determines pharmacological and behavioral drug action and may, thus, give rise for an expanded system’s approach of psychoactive drug use and addiction.