tDCS Effects on Resisting Smoking: Dose Ranging Study
Condition: Nicotine Addiction
MeSH terms: Tobacco Use Disorder
Study type: Interventional

Summary: 
      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.
    

Detailed description: 
      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.
    

Intervention name(s): transcranial direct current stimulation (tDCS)
Intervention type(s): Device
Intervention description(s): Active tDCS: A neuroConn DC-Stimulator Plus will apply a constant direct current (1.0 mA to 2.0 mA via 5x7 electrode) to the left dorsal lateral prefrontal cortex. Each participant will receive anodal stimulation for a period of 20 minutes. For anodal stimulation over the left DLPFC, the anodal electrode will be placed over the left F3 and the cathodal electrode over the right supraorbital area (international EEG 10/20 system).
Sham tDCS: During sham tDCS, a 1.0 mA to 2.0 mA current will be delivered for approximately 30 seconds before being extinguished over a course of seconds. Again, the anodal electrode will be placed over the left F3 and the cathodal electrode over the right supraorbital area. Most participants cannot distinguish between real and sham tDCS.
Other intervention name(s): tDCS, neuroConn DC-Stimulator Plus
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Triple (Participant, Investigator, Outcomes Assessor)
Primary purpose: Other