Hot Topic: [Extinction of Drug-Seeking Behavior (Guest Editor: Olive Foster)]

ABSTRACT

Some of the key defining characteristics of drug addiction (substance dependence) is the persistence of drug-seeking behavior despite attempts at abstinence, adverse health and legal consequences, and impaired social, occupational or academic functioning [1]. From a behavior modification standpoint, extinction refers to the gradual and intentional reduction of a maladaptive behavior, such as drug-seeking or drug self-administration behavior. From a cognitive-behavioral therapeutic perspective, extinction refers to a gradual and intentional reduction in psychological and/or physiological responses, such as autonomic nervous system activation and drug craving, to drug-associated stimuli. In the latter sense, extinction is essentially a “desensitization” process that is performed via cue exposure therapy (CET). During CET, addicts are presented with pictures of or actual physical exposure to drug-related stimuli such as drug paraphernalia (i.e., crack pipes), drug-related olfactory stimuli (i.e., the aroma of alcohol or cigarette smoke), or even drug self-administration contextual environments. Over time, the conditioned psychological and physiological responses to drug-associated stimuli extinguish. Similar cue exposure therapy procedures, such as exposure plus response prevention, are successfully used for the treatment of anxiety disorders including disabling phobias, obsessive-compulsive disorder, and post-traumatic stress disorder. Unfortunately, the success rates of cue exposure therapy in preventing relapse in former addicts are modest at best [2]. Most addiction counselors, psychiatrists, and other treatment professionals attribute the meager success rate of cue exposure therapy to the context specificity of extinction. That is, while an addict might become desensitized to the craving evoked by handling a pack of cigarettes in a therapist's office, this extinction of cue-induced drug craving fails to generalize to other contexts, such as actual “real world” environments which the addicts encounter in their everyday lives. Similar problems of context specificity have often impeded the successful extinction of maladaptive responses to fear- and anxiety-provoking situations or stimuli. As a result of the relatively poor outcomes that have resulted from extinction-based approaches, increased knowledge about the neural substrates that underlie extinction, an active form of learning, is greatly needed in order to improve existing behavioral modification and cognitive-behavioral therapies for the treatment of drug addiction.