tDCS Effects on Resisting Smoking: Dose Ranging Study

Overview

Behaviors such as tobacco use, unhealthy diet, and sedentary behavior have far-reaching health implications. These modifiable behaviors account for a substantial proportion of deaths from cancer, cardiovascular disease and diabetes, and take a significant economic toll. Yet, many unhealthy behaviors are very resistant to change, despite widespread knowledge of the risks. Although theories of behavior change have been advanced to explain the persistence of these behaviors, few consider the neurobehavioral underpinnings. These approaches also fail to address a fundamental aspect of behavior change - an individual's ability to exert sufficient self-control to overcome temptations for immediate gratification and/or to maintain attention to long-term goals. With advances in the neuroimaging field, the investigators are learning where and how self-control over decisions and behaviors is executed in the brain. This work points to the central role of neural activity in the dorsolateral prefrontal cortices (DLPFC) in self-control processes that contribute to healthy choices. Further, emerging evidence shows that activity in the prefrontal cortices and cognitive control circuits can be modulated using a noninvasive and safe intervention: direct current transcranial stimulation (tDCS). The investigators pilot study, IRB study #820231, demonstrated that a single session of 1mA tDCS increased the ability to resist smoking in a validated smoking lapse paradigm. The current study will use a between-subject design to investigate the dose/response relationship between tDCS (administered at 1mA, 2mA, or sham stimulation for three sessions) and ability to resist smoking.

This trial will use a between-subject single blind design in which participants will be randomized to one of three tDCS dosage groups (1mA, 2mA or sham) and will receive three 20 minute sessions of the same dosage over the course of 1 week before completing a 7 day quit attempt. Eligible participants will complete an Intake Visit (week -1) for final eligibility determination, and complete baseline measures (if eligible). Participants will then be randomly assigned to one of the three dosage groups (1mA, 2mA or sham) and will attend three identical tDCS resist-smoking sessions (study days 1, 3, \& 5) during which they will receive 20 minutes of their assigned tDCS dosage and complete cognitive tasks and a resist smoking paradigm. During the resist smoking sessions, participants will receive a session of their assigned dosage of tDCS for 20 minutes while being exposed to in vivo smoking cues (their cigarette pack, cigarettes, an ashtray). Participants will not be informed of their dosage condition. During and after the tDCS session, participants will have the opportunity to smoke in the approved smoking lab. The investigators will measure time to first cigarette and subsequent ad libitum smoking during the resist smoking paradigm. Following Session 3 participants will receive a 20 minute coaching session from a trained smoking cessation counselor to help them prepare for a 7-day quit attempt. During the 7-day quit attempt participants will be asked to attend 4 monitoring visits (study days 6, 8, 10 \& 12) to confirm smoking status.