The purpose of this pilot study is to evaluate the feasibility, acceptability, and preliminary efficacy of an intervention to promote smoking cessation among light smokers.

The three-arm randomized controlled trial compares Arm 1) standard smoking cessation plus support text messages, 2) enhanced cue exposure treatment (lab-based + interactive SMS texting) + D-cycloserine placebo, Arm 3)will include a combination of cognitive behavioral cessation counseling, enhanced cue exposure treatment (lab-based + interactive SMS texting) and a cognitive-enhancing drug - D-cycloserine. In addition to an in-person screening visit, we will conduct three in-person treatment visits and an inperson follow-up visit.

Inclusion Criteria:

• Age: ≥18 years old
• Able to read and understand English or Spanish
• Cognitively able to provide informed consent
• Smoke 1-10 cigs/day on at least 4 days in the past month
• Express a desire to quit smoking in the next 30 days
• Access to a cell phone that can send and receive SMS text messages and take and send pictures

Exclusion Criteria:

• Hypertension with a screening blood pressure over 160/100;
• Hypotension with a screening blood pressure of systolic <90 mm Hg, diastolic <60 mm Hg;
• Participants with a history of hypertension may be allowed to participate in the study if the study physician or physician assistant determines that the condition is stable, controlled by medication, and in no way jeopardizes the individual's safety;
• Coronary heart disease, diagnosed by coronary angiogram;
• History of major heart attack;
• Major cardiac rhythm disorder determined by study MD;
• Chest pain in the last month (unless history, exam, indicate a non-cardiac source);
• Symptomatic cardiac disorder (valvular heart disease, heart murmur, heart failure);
• Diagnosis of severe liver disease or kidney disorder;
• Major gastrointestinal problems or disease (Celiac, Crohn's, Ulcerative Colitis)
• Bleeding ulcers in the past 30 days;
• Current, advanced lung disorder/disease (COPD, emphysema);
• Migraine headaches that occur more frequently than once per week;
• Recent, unexplained fainting spells;
• Problems giving blood samples;
• Diabetes not controlled by diet and exercise alone;
• Current cancer or cancer treatment in the past six months (except basal or squamous cell skin cancer);
• HIV, Hepatitis B, or Hepatitis C;
• History of Tuberculosis or recent positive PPD;
• Other major medical condition;
• Current symptomatic, uncontrolled psychiatric disease;
• Diagnosis of serious mental illness, including bipolar disorder and schizophrenia;
• Suicidal ideation within the past month or lifetime occurrence of attempted suicide;
• Current (within 2 weeks) depression determined by PHQ-9 score > 9 or > 0 on item #9
• Bulimia or anorexia;
• Pregnant or nursing;
• Use (within the past 30 days) of:
• Illegal drugs (or if the urine drug screen is positive for Cocaine, Amphetamine, Opiates, Methamphetamines, PCP, Benzodiazepines, or Barbiturates), unless prescribed for management of acute symptoms (tooth extraction, recent surgery);
• Experimental (investigational) drugs;
• Psychiatric medications including antidepressants (MAOIs, St. John's Wort), lithium, anti-psychotics, or any other medications that are known to affect smoking cessation (e.g. clonidine);
• Wellbutrin, bupropion, Zyban, Chantix, varenicline, nicotine patch, nicotine replacement therapy or any other smoking cessation aid.
• Use of cigars, cigarillos, pipes, Hookah, dissolvable nicotine, snuff, chewing tobacco , or e-cigarettes within the past 30 days;
• Positive result on AUDIT-C;
• Self-report of marijuana use ≥ 4 days per week;
• Significant adverse reaction to D-cycloserine in the past;
• Current or recent (in the past 30 days) participation in another smoking study at our Center or another research facility

In the comparator standard counseling, one enrolled patient withdrew prior to completing the baseline survey. Three participants in the active comparator arm did not complete the baseline survey.

2 months

Findings are not conclusive due to the pilot nature of the study.