using non-invasive brain stimulation (tdcs) with varenicline for treating tobacco dependence

Conditions: Tobacco Dependence; Smoking Cessation; Tobacco Smoking; Tobacco Use Disorder; Substance Use Disorders; Molecular Mechanisms of Pharmacological Action; Physiological Effects of Drugs

Summary: the addition of tdcs as an adjunct to pharmacotherapy is a novel approach but one that is grounded in a growing evidence-base.the primary objective of this research is to provide preliminary evidence of the effectiveness of tdcs as an adjunct treatment to pharmacotherapy for smoking cessation. the investigators hypothesize that the addition of active tdcs to the left dlpfc will improve the effectiveness of varenicline as reflected by higher quit rates at end of treatment compared to the sham group. smoking status will be biochemically confirmed at various time points using expired cotinine measures. furthermore, the investigators will be collecting neuroimaging (fmri) data as well as measures of attentional bias to explore the neurological and physiological correlates from using adjunct tdcs and varenicline therapy.

while varenicline on its own is the most effective medication for smoking cessation, long-term abstinence is still relatively poor. the primary objective of this study is to evaluate the effectiveness of adjunct active tdcs with varenicline in treating tobacco dependence. this study is a double-blind, sham-controlled, randomized clinical trial where 50 daily dependent treatment seeking smokers will be recruited at the nicotine dependence clinic in toronto, canada. participants will be receiving twelve weeks of varenicline treatment (1mg b.i.d.) and randomized 1:1 to either active tdcs (active: 20 minutes at 2 ma) or sham tdcs (30 seconds at 2 ma, 19.5 minutes at 0 ma), daily (m-f) for the first 2 weeks and then every 2 weeks for the next 10 weeks. there will be 2 fmri scans at baseline and 1 scan at end-of-treatment. eye-tracking viewing tests will be conducted at baseline, weeks 4, 8, 12 and at 6 months follow up. during the 6 month follow-up, participants will be answering questions regarding their smoking behaviour and craving. smoking status will be biochemically confirmed at each study visit using expired cotinine.

Eligibility criteria:
inclusion criteria: * male or female * aged 19-65 * treatment seeking smoker * daily smoker of cpd\>8 * able to attend daily appointments for tdcs for the first 2 weeks and booster sessions for the next 10 weeks. * wiling to undergo 3 fmri sessions exclusion criteria: * current/recent dsm-iv axis i diagnosis * current use of psychoactive drugs or medications * history of seizures/epilepsy * current use of nrt, e-cigarettes or other medications for smoking cessation * metal embedded in skull or implanted electrical devices * no head injury (concussion or loss of consciousness for more than an hour) * contraindications to fmri * contraindications to varenicline

Keywords: smoking cessation medication smoking treatment tobacco treatment quitting smoking varenicline transcranial direct current stimulation neuroimaging fmri attentional bias eye-tracking dependence addiction cigarettes biochemical confirmation cue reactivity reward anticipation diffusion tensor imaging resting state functional connectivity bold fmri quantitative t1