Commentary on Bechara et al.’s “A Neurobehavioral Approach to Addiction: Implications for the Opioid Epidemic and the Psychology of Addiction”

Abstract

The article by Bechara et al. (2019; p. 96) rightly brings to prominence the importance of neurobehavioral research in the investigation of the underlying mechanisms of drug abuse and is particularly timely in the context of the U.S opioid epidemic. They refer to a number of theories of addiction that focus on different aspects of the phenomena associated with chronic drug misuse before a detailed account of the special properties of opioids in processing pain as well as reward and a survey of the role of “willpower” and related cognitive control mechanisms in the understanding and possible treatment of drug abuse. Bechara et al.’s emphasis on theoretical mechanisms is much needed to make progress in reducing initiation, maintenance, and relapse in opioid addiction. In this spirit, I offer a few observations. To begin, the opponent-motivational-processing perspective is rejected by Bechara et al. in its simple form as an account of opioid addiction because it appears to predict that “cold turkey” should eventually cure heroin addiction, whereas in fact it is a chronic, relapsing disorder. However, there is evidence that withdrawal symptoms can readily be classically conditioned (e.g., Goldberg & Schuster, 1967; Kenny, Chen, Kitamura, Markou, & Koob, 2006), which is consistent with the retrieval of such symptoms as aversive memories that sustain addictive behavior. Thus, it seems premature to discard this theory. There is also an important instrumental (voluntary behavior) component to the opponent theory, in that it is based on the negative-reinforcement principle that heroin-seeking occurs in anticipation of the withdrawal state, which can be postponed or escaped from by taking the drug. In that sense, heroin seeking is analogous to avoidance behavior, which is well known to be highly resistant to extinction, and exhibits the normal phenomena of extinction, such as spontaneous recovery, which again would readily promote relapse. Instrumental appetitive behavior also plays an important role in drug seeking, as well as in drug use itself, which is most directly studied in animals in terms of schedules in which the drug is administered intravenously (or via other routes) consequent on instrumental responding, often in the presence of drug-related cues (discriminative stimuli and conditioned reinforcers). Such instrumental behavior has been demonstrated for virtually all drugs of abuse but has been most studied for stimulant drugs, such as cocaine and amphetamine. A modern cognitive account of such behavior (e.g., Balleine & O’Doherty, 2010) refers to “goal-directed behavior,” which is governed by specific neural circuits in the corticostriatal system; in the rat, this probably implicates the prelimbic cortex and dorsomedial striatum, equivalent to the caudate nucleus in primates. However, with training, instrumental behavior can become relatively autonomous of the goal and is then referred to as being habitual. This transition is associated with a devolution of control to other corticostriatal systems, notably to the sensorimotor cortex and the dorsolateral striatum (putamen in primates). Despite this transition, the flow of behavior depends on a constant interleaving and blending of goal-directed and habitual components. This theory, based largely on studies using food as the reward, which attempts to integrate all of the major 862034 PSIXXX10.1177/1529100619862034RobbinsCommentary research-article2019