In this study, potential associations between several genetic polymorphisms and nicotine dependence will be examined. The relative reinforcing efficacy of cigarettes using the forced-choice procedure will be assessed. In addition, reactivity to smoking cues using a reliable procedure will be conducted.

It is known that cannabinoid and dopamine receptors can be important modulators of response to nicotine and its associated cues. In this study participants will be genotyped to determine whether there is a relationship between CB1 or D3 genes and the reinforcing properties of nicotine or the subjective effects of nicotine-associated cues. In one session, participants will chose between two different cigarettes, each with different properties. In another session, physiological responses and craving will be measured when presented with cues that remind participants of nicotine. At some point during the study, blood will be collected for genotyping and this will processed to study whether CB1 or D3 genotype influences these responses to nicotine or cues.

Inclusion Criteria:

1. 19-64 year old males and females
2. smoking at least 10 cigarettes per day for at least 1 year
3. positive urinary cotinine
4. medically and psychologically healthy as determined by screening criteria

Exclusion Criteria:

1. definite plan to reduce or quit tobacco use during the course of the study
2. treatment for tobacco dependence in the past 3 months
3. use of nicotine replacement products, bupropion, or varenicline in the past 3 months
4. consumption of more than 15 alcoholic drinks per week during the past month
5. use of any illicit drug more than twice per week during the past month
6. current use of any medication that would interfere with the protocol in the opinion of PI
7. under the influence of a drug or alcohol at any session
8. pregnant, nursing, or become pregnant during the study

Otherwise healthy smokers will be recruited