Drugs as instruments: A new framework for non-addictive psychoactive drug use

Introduction

Miller and colleagues open by noting a central empirical puzzle: most people who consume psychoactive drugs do not become addicts, yet prevailing neurobiological theories treat non-addictive use mainly as a necessary precursor to addiction rather than as a widespread, stable behavioural pattern in its own right. Epidemiological figures are cited to show the scale of drug, alcohol, and tobacco use alongside the comparatively smaller fraction of users who meet diagnostic criteria for dependence. The authors argue that without a framework for non-addictive use it is difficult to conceptualise how transitions to addiction occur or why the majority of users remain non-addicted. To fill that gap, the paper proposes a new neurobiological and evolutionary framework called "drug instrumentalization." Rather than seeing drug taking primarily as hijacking reward systems, Miller and colleagues characterise many instances of non-addictive use as learned, purposive behaviours in which people consume psychoactive substances to induce mental states that facilitate the performance of non-drug goals. The Introduction sets up the aims of the article: to define drug instrumentalization, list plausible instrumentalization goals, outline proximate neuropharmacological mechanisms, propose a taxonomy of drug-related memories and a learning model, and to consider evolutionary and policy implications of treating non-addictive use as an adaptive, learned strategy that nevertheless carries risks.