AAT + tDCS to Reduce Cue-induced Craving and Smoking Behavior

Overview

Smokers are highly reactive to smoking-related stimuli and report that this cue reactivity (CR) is a major obstacle to quitting. To date, no pharmacologic methods attenuate CR, and attempts to diminish it with traditional cue exposure treatment (CET) have not proven effective. The proposed study will test a highly novel cue-based smoking treatment adjunct combining an Approach/Avoidance Task (AAT) with brain stimulation via tDCS applied to the dorsolateral prefrontal cortex (dlPFC) during personalized multi-cue exposure; the goal of which is to discover an effective means of reducing cue reactivity and daily smoking, and increasing intent and confidence to quit, among high treatment-interest smokers.

Exposure to smoking-related cues robustly increases self-report craving and immediate subsequent smoking. This cue-reactivity (CR) is an often-reported obstacle to quitting among smokers. Unlike methods to diminish abstinence-induced craving, which have been highly successful with the advent of nicotine replacement therapies (NRTs), pharmacotherapies have not been shown to diminish smoking-related reactivity to cues. Past behavioral methods to reduce smokers' CR, most commonly extinction training through cue-exposure treatment (CET), have also consistently failed. Review of past CET studies reveals that this failure is largely due to several methodological shortcomings including: (1) presenting only proximal cues (e.g., cigarettes, ashtrays), (2) conducting passive unreinforced exposure to these limited cues, and (3) achieving only limited new learning. The researchers extensive past cue work makes them uniquely qualified to remedy these flaws by designing and testing novel CET methodology incorporating contemporary techniques and technology to reduce CR and relieve smokers of this ubiquitous source of relapse risk. The researchers propose three methods to improve CET. First, using well-tested methods for personalizing smoking cues and presenting numerous proximal, environment, and people cues in combination, the proposed cue exposure will better capture and target the cue-rich situations most likely to trigger smokers' strongest CR. Second, rather than repeated passive unreinforced exposure to cues, smokers will engage in active re-training of approach biases toward their personal smoking stimuli using an Approach/Avoidance Task (AAT), a method shown to activate the dorsolateral prefrontal cortex (dlPFC), a brain region associated with both cognitive control over craving and deactivation of drug reward systems. Third, to enhance new learning, smokers will undergo non-invasive transcranial direct current brain stimulation (i.e., tDCS) of the dlPFC. Although the researchers propose each method, AAT and tDCS, should independently reduce smokers' CR to their most salient cues, providing AAT with simultaneous tDCS (AAT+tDCS) should synergistically attenuate CR by better increasing cortical excitability in the dlPFC. To assess this, a 2 x 2 active and sham-controlled test of AAT and tDCS during personalized multi-cue exposures will be used to examine pre-post training changes across several measures of smoking-related cue reactivity (cue-induced craving, cue-provoked smoking topography, and attentional bias measures of Evoked Response Potentials (ERPs) and reaction time), as well as changes in daily smoking and confidence and intent to quit pre-post training and at 1 week and 1-month follow up. The goal of this work is to develop an efficacious treatment adjunct that better prepares smokers to confront cues when they try to remain quit.