tDCS plus varenicline to help people quit smoking

Using Non-Invasive Brain Stimulation (tDCS) as an Adjunct to Varenicline for the Treatment of Tobacco Dependence: a Randomized Controlled Trial

PHASE4 · Centre for Addiction and Mental Health · NCT06798324

This will test if adding noninvasive tDCS brain stimulation to varenicline helps adults who smoke at least 8 cigarettes a day quit and stay smoke-free.

Quick facts

PhasePHASE4
Study typeInterventional
Enrollment160 (estimated)
Ages18 Years to 85 Years
SexAll
SponsorCentre for Addiction and Mental Health (other)
Locations1 site (Toronto, Ontario)
Trial IDNCT06798324 on ClinicalTrials.gov

What this trial studies

Adults who smoke ≥8 cigarettes per day and are seeking treatment are randomized to receive either active or sham transcranial direct current stimulation (tDCS) in addition to varenicline (1 mg twice daily). The tDCS schedule includes 10 daily sessions over the first two weeks (Monday–Friday) followed by five biweekly booster sessions, with in-person follow-ups at 6 and 12 months to measure smoking behavior and safety. Primary outcomes are short-term and sustained abstinence rates and comparison of adverse events between the active and sham groups. The trial is conducted at the Centre for Addiction and Mental Health in Toronto and excludes participants with seizure history, implanted electrical devices, recent use of other cessation medications, or unstable psychiatric illness.

Who should consider this trial

Good fit: Ideal candidates are adults aged 18–85 who smoke at least 8 cigarettes per day, are seeking cessation treatment, can attend daily clinic visits for two consecutive weeks plus booster and follow-up visits, and have no major medical or implant contraindications.

Not a fit: People with a history of seizures or significant head trauma, implanted electrical devices, current pregnancy, recent use of other smoking-cessation medications, regular use of non-cigarette nicotine products, or unstable psychiatric illness are unlikely to be eligible or to benefit from this intervention.

Why it matters

Potential benefit: If successful, adding tDCS to varenicline could increase quit rates and help more people stay smoke-free long term using a noninvasive adjunct.

How similar studies have performed: A prior pilot from the same lab reported that adjunct active tDCS doubled varenicline's effectiveness at end of treatment and other small tDCS studies in addiction show promise, but larger confirmatory trials remain limited.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Be able to provide informed written consent
* Stated willingness to comply with all study procedures
* Age 18-85 years
* Smoke ≥ 8 cigarettes per day (CPD)
* Is seeking treatment for tobacco dependence
* Willing to attend the required clinic appointments (Two consecutive weeks, Monday through Friday)
* Otherwise healthy (i.e. not suffering from any major illness/condition that would impact their participation in the study)

Exclusion Criteria:

* Use of smoking cessation medication (e.g. buproprion, varenicline, NRT, cytisine) in the past 3 months
* Current regular use of nicotine-containing products besides cigarettes (e.g. electronic cigarettes, etc.)
* Unstable psychiatric illness that would adversely impact study participation and compliance (determined by the QI)
* History of seizures/epilepsy
* Lifetime history of concussions or head traumas
* Current pregnancy or plans to become pregnant
* Current pacemakers or implanted electrical devices
* Current metal embedded in the skull
* Presence of skin lesions, open wounds, or bruising at stimulation sites; or
* Contraindications to varenicline use (e.g. pregnant/breastfeeding, alcohol dependence, kidney disease/renal impairment, known hypersensitivity to varenicline)

Where this trial is running

Toronto, Ontario

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.

View on ClinicalTrials.gov →

Conditions: Nicotine Dependence, Tobacco Smoking, Smoking Cessation, Nicotine Use Disorder, Tobacco Use Disorder, Substance Use Disorders, Smoking, Brain Stimulation

Last reviewed 2026-05-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.