Nicotine Reinforcement and Aversion in Young Adult Light Smokers

Aim #1: To assess the threshold reinforcing dose and dose-effect curve for IV NSA at low doses in young adult LITS.

Hypothesis #1A: The threshold reinforcing doses for IV NSA will be between 0.0125 to 0.1 mg/70 kg.

Hypothesis #1B: The dose-effect curve for NSA will differ between males and females with relatively flat curve in female smokers.

Aim #2: To assess the threshold and dose-effect curve for the positive and negative/aversive subjective effects of IV nicotine at low doses and its relationship to nicotine reinforcement.

Hypothesis #2 A: The threshold for the positive effects will be between 0.0125 to 0.1 mg/70 kg, for the negative/aversive effect it will be ≥ 0.1 mg/70 kg.

Hypothesis #2B: Nicotine reinforcement will be positively correlated with the positive and negatively correlated with the negative/aversive subjective effects of IV nicotine.

Exploratory Aims: To examine the influence of nicotine clearance rate on nicotine reinforcement threshold and dose-effect curve.

Inclusion criteria

1) Female and male smokers, aged 18 to30 years, who have been smoking for at least a year, and a life-time consumption of at least 100 cigarettes; 2) smoke more frequently than once a week and ≤5 cpd; 3) FTND score <3 indicating no or minimal evidence for nicotine dependence; 4) urine cotinine levels >100 ng/mL indicating smoking status and a level <1000 mg/mL consistent with nicotine intake of LITS; 5) not seeking treatment at the time of the study for nicotine dependence; 6) in good health as verified by medical history, screening examination, and screening laboratory tests; 7) for women, not pregnant as determined by pregnancy screening, nor breast feeding, and using acceptable birth control methods.

Exclusion criteria

1) history of major medical illnesses that the physician investigator deems as contraindicated for the subject to be in the study; 2) requirement of any form of regular psychotropic medication (antidepressants, antipsychotics, or anxiolytics) or psychiatric diagnosis and treatment for psychiatric disorders including major depression, bipolar disorder, schizophrenia in the past 6 months; and 3) current dependence to alcohol or any other recreational or prescription drugs and; 4) daily use of smokeless tobacco products or exclusive daily use of e-cigarettes (non-daily users will be included).