The purpose of this study is to determine whether the abuse liability of cigarettes with altered composition (cigarettes differing in composition; e.g., tar levels, amount of sugar, casings) is reduced relative to standard composition cigarettes.

The proposed study will determine the abuse liability of altered composition cigarettes compared to standard cigarettes using a behavioral economics abuse-liability approach. Behavioral economic demand analysis constitutes a comprehensive examination of drug reinforcement and abuse liability. Laboratory determination of cigarette consumption under various response requirements will occur before and after 3 weeks of at-home exposure, with participants randomized to cigarettes varying in composition to determine the role of experience on the abuse-liability of various cigarettes. Abuse liability will be assessed by 2 essential demand metrics: lower demand intensity and increased demand elasticity, as well as other demand metrics and subjective ratings of "liking". The study will also determine the degree to which altered composition cigarettes may substitute for standard composition cigarettes - testing whether an altered composition policy would achieve the goal of reducing standard cigarette consumption.

Inclusion Criteria:

1. Age 18 years or older
2. Smoke at least five cigarettes per day
3. Have an expired carbon monoxide level of more than 8 ppm or a urinary cotinine level of more than 100 ng per milliliter
4. Have a Fagerström Test for Nicotine Dependence score of at least 5 upon screening

Exclusion Criteria:

1. The intention to quit smoking in the next 30 days
2. The use of other tobacco products in addition to machine-manufactured cigarettes on more than 9 of the previous 30 days
3. Use of "roll your own" cigarettes as an exclusive form of smoking
4. A serious medical or psychiatric disorder or unstable condition
5. Any positive toxicological screening for illicit drugs other than cannabis will be excluded
6. Women who are pregnant, plan to become pregnant or are breast-feeding