Abstract

Both animal and human neuropsychological models suggest that addiction is characterized by alterations in two complementary systems: (i) the impulsive system, which promotes rapid, unplanned, strongly automatized drug-seeking responses; and (ii) the reflective-executive system, which fails to exert context-mediated inhibitory control over these responses, thus neglecting more adaptive goals. Nonetheless, the study of the link between impulsivity and human addiction raises important research challenges, including: (i) the fact that impulsivity is a poorly understood mulfaceted construct that can be approached from very different views within personality and neuropsychology; (ii) the fact that altered impulse control may both predate drug use initiation and result from drug exposure; and (iii) the fact that emotional states play a key but neglected role on the association between impulsivity and addiction. Here I will present results from a number of studies using neuropsychological and personality measures of impulsivity in samples of cannabis, psychostimulant and opioid polysubstance abusers. These studies provide empirical evidence of altered performance of different groups of drug abusers on a number of neuropsychological measures of impulsivity (including response inhibition, delay-discounting, reflection impulsivity and decision-making paradigms), and of the link between emotional states, impulsive behavior and severity of addiction; negative emotion-driven impulsivity importantly predicts the severity of alcohol and drug use, employment, legal and social problems in polysubstance abusers. These results can be understood in terms of a somatic-marker model of addiction, which propose that developmentally or drug-shaped altered emotional signaling contribute to impulsive decision-making in drug abusers.