Nicotine Withdrawal Symptoms and Smoking Relapse

• INCLUSION CRITERIA:

All Subjects must:

• Be between the ages of 18-65.
• Be right-handed. Assessment tool(s): Edinburgh Handedness Inventory.
• Be in good health. Justification: Many illnesses may alter fMRI signals as well as cognitive processes and neural functioning. Assessment tool(s): Participants will provide a brief health history during phone screening, and undergo a medical history and physical examination with a qualified IRP clinician.
• Be free of current moderate to severe DSM-V Substance Use Disorder on any drug, except nicotine in smokers. Those with past moderate to severe use disorder on substances may be included, provided they are in sustained remission (and not on maintenance therapy for opioid use disorder) and are not intoxicated on the day of the imaging session. Justification: Moderate to severe use disorder on other substances may result in unique CNS deficits that could confound results and introduce excessive variance, while mild substance use disorder and substance use disorder in remission are common in community samples of smokers. Assessment tool(s): Computerized SCID or comparable assessment and DSM-5 substance use disorder assessment.
• Be able to abstain from alcohol and other recreational drugs for 24 hours before each imaging session, and able to moderate caffeine intake 12 hours before each imaging session. Justification: Recent substance use, including alcohol, and caffeine modulate neural functioning in a way that would complicate data interpretation. Assessment tool(s): Self-report, breathalyzer, and urine toxicology screen with follow up neuromotor assessment to ensure absence of acute impairment with positive urine test.
• Smokers must meet the additional criteria:
• Have a urine cotinine level corresponding to smoker status for the specific test being used, typically corresponding to a urine cotinine above about 200 ng/ml, and have been smoking for at least 1 year. Justification: The present protocol is interested in neurobiological mechanisms that underlie nicotine withdrawal, and is thus contingent on the presence of nicotine dependence. Assessment tool(s): Selfreport, commercial urine cotinine test corresponding to smoker status for the specific test being used, typically corresponding to a urine cotinine above about 200 ng/ml.
• Be able to abstain from smoking for 12 hours prior to MRI-tDCS study sessions. Justification: The present protocol will investigate the effect of acute nicotine withdrawal on cognitive processes and response to tDCS. Assessment: Self-report and expired CO levels
• In addition, non-smokers must meet:
• Not have a history of daily cigarette smoking or have used any nicotine products continuously lasting more than a month, and no smoking or continuous use of any nicotine products within the past year. Assessment Tools: Self-report, urine cotinine test, and expired CO levels.

EXCLUSION CRITERIA

All participants will be excluded if they:

• Are not suitable to undergo an fMRI experiment due to certain implanted devices (cardiac pacemaker or neurostimulator, some artificial joints, metal pins, surgical clips or other implanted metal parts), body morphology, or claustrophobia. Justification: MR scanning is one of the primary measurement tools used in the protocol. Assessment tool(s): Prospective participants will fill out an MRI screening questionnaire and undergo an interview with an MR technologist. Questions concerning suitability for scanning will be referred to the MR Medical Safety Officer. Prospective participants will be questioned about symptoms of claustrophobia and placed in the mock scanner during their first visit to assess for possible difficulty tolerating the confinement of the scanner and for ability to fit into the scanner.
• Have musculoskeletal abnormalities restricting an individual s ability to lie flat for extended periods of time. Justification: MR scanning sessions require participants to lie flat on their backs and remain perfec