Varenicline is the most effective smoking cessation therapy available. Nevertheless, most smokers using varenicline relapse within the first few months after quitting. Varenicline is hypothesized to help smokers to quit in part by reducing the reinforcing effects of smoking during the standard 1-week pre-quitting treatment phase. Learning theory and previous human and animal research support the hypothesis that a longer period of varenicline treatment prior to the target quit date (TQD) will lead to greater reductions in smoking before quitting, and higher long-term cessation rates, compared to standard varenicline treatment. Building on promising preliminary clinical data, the study tests these hypotheses with a full-scale randomized clinical trial (RCT). 320 treatment-seeking smokers will be randomized to a standard run-in group (3 weeks of placebo, followed by the standard 1 week of pre-TQD varenicline) or an extended run-in group (4 weeks of pre-TQD varenicline). Both groups will receive brief individual cessation counseling and 11 weeks of post-TQD varenicline. The primary outcome measure will be bio-verified continuous abstinence at end-of-treatment (weeks 8-11 post-quit; cessation at 26-weeks post TQD will also be examined. Hypothesized mediating mechanisms (e.g., smoking reinforcement) will be evaluated by behavioral, physiological, and subjective measures assessed both in the lab and using real-world, real-time electronic momentary assessments (EMA). The investigators predict that long-term, bio-verified smoking cessation will be improved among the extended run-in group compared to the standard run-in group. The investigators further predict the improved clinical outcomes with extended run-in varenicline will be explained (or mediated) by greater pre-quit reductions in smoking reinforcement among the extended run-in group compared to the standard run-in group. The significance of this work is clear: The project aims to make best available treatment for smoking cessation even better, using a method that is ripe for dissemination and an approach that will elucidate critical mechanisms to target in the next generation of treatment enhancement.

Inclusion Criteria:

• Smoking at least 10 cigarettes per day (CPD) for the past 6 months and expired-air carbon monoxide (CO) >7 at intake. NOTE: To reduce exclusion of Black participants, the CPD criterion was reduced to 5 and the carbon monoxide criterion was eliminated in November, 2019.
• At least moderately motivated to quit smoking and intention to make a quit attempt with varenicline 1 month after treatment begins.
• Planning to remain in western New York (NY) during the study period
• Willing to use varenicline and to refrain from other cessation treatments and tobacco products during the study period.
• English speaker
• To be intent-to-treat (ITT), the participant must complete Lab Visit 1 and meet minimal completion rate for real-world (EMA) assessments.

Exclusion Criteria:

• Use of other tobacco products, including e-cigarettes, in past 7 days

• Use of smoking cessation medication, including nicotine replacement therapy, in the past 14 days

• Prior allergy/hypersensitivity to varenicline

• Pregnant or breast-feeding

• Substance use:

  • Alcohol: AUDIT score > 15 at intake, suggestive of alcohol dependence and warranting treatment; for those with scores between 8 and 15, the investigators will advise reducing drinking).

  • Medical treatment for substance use (SU) in past 3 months, including Suboxone (buprenorphine) and methadone (at phone screen)

  • Using a combination of the National Institute on Drug Abuse (NIDA) modified ASSIST (4-26 = moderate risk; 27+ = high risk) and urine toxicology screen (both at intake):

    • Cannabis: ASSIST=27+ (tox screen not used)
    • Cocaine: ASSIST=7+ OR positive tox screen
    • Methamphetamine: ASSIST=7+ OR positive tox screen
    • Inhalants, hallucinogens, sedatives, or sleeping pills: ASSIST score = 7+
    • Prescription stimulants: With prescription, ASSIST 27+; Without prescription, ASSIST 7+
    • Opioids: With prescription, ASSIST 27+ (note ineligible if prescription is for buprenorphine or methadone); Without prescription, ASSIST 7+ OR positive tox screen

(Note: ASSIST 4+ modified to 7+ in 2018 to avoid excluding people with past SU problems. clinicaltrials.gov edited 12/18/18)

• Psychiatric:

  • Antipsychotic medications
  • Lifetime history of schizophrenia or bipolar disorder
  • Evidence of current major depression (per Patient Health Questionnaire (PHQ-9) at intake
  • Past 10 years suicidal ideation (SI) / behavior. At intake, all of the following are exclusionary on the baseline Columbia-Suicide Severity Rating Scale (Posner et al., 2008): SI without intent (C-SSRS #1, #2, or #3), if any intensity rating (Frequency, Duration, Controllability, Deterrents, or Reasons for Ideation) is > 2; SI with intent (C-SSRS #4, or #5), regardless of intensity ratings; Suicidal Behavior (any suicide attempt, interrupted attempt, aborted attempt, or suicide preparatory acts or behavior on the C-SSRS).

• Any medical condition, illness, disorder or concomitant medication that compromises participant safety or treatment, as determined by the Principal Investigator and/or Study Physician.

• Inability to provide informed consent or complete any of the study tasks as determined by the Principal Investigator and/or Study Physician.

Approximately equal numbers of men and women will participate.

We plan to share study data through the NIDA-supported NAHDAP repository. IPD to be shared include baseline participant characteristics, intervention group, smoking abstinence, and adverse events.

2023. We are currently awaiting confirmation from NAHDAP that our archival plan fits their expectations. Data will be available indefinitely (as long as NAHDAP is supported).

Public release; anyone who registers on the website.

Adverse events were assessed at intake and clinic visits which occurred across the first two months of treatment.

At each visit, participants completed a 32-item symptom checklist, as in prior work.

Suicidality was assessed at each visit with the Columbia Suicide Severity Rating Scale.

Here, data on adverse events are reported for each of three treatment phasesphases (pre-treatment phase [intake visit & clinic visit 1); pre-quit run-in manipulation phase [clinic visits 2&3; extended run-in group taking varenicline, standard run-in group taking placebo], and early quit phase [clinic visits 4&5]).](streamdown:incomplete-link)