Nicotine Facilitation of Conditioned Place Preference to Food Reward in Humans

Abstract

Background

Nicotine has recently been shown to enhance the motivational value of non-nicotine stimuli in nonhumans. To investigate whether nicotine also enhances reward in humans, we used a virtual translation of the conditioned place preference (CPP) paradigm to examine nicotine’s reward-enhancing effects using a low-dose 2 mg nicotine lozenge targeted to a mild use population. Methods: Sixty-eight nicotine-using undergraduates were randomly assigned to receive either a 2 mg nicotine or placebo lozenge prior to conditioning. During each of six, three-minute conditioning sessions, participants were confined to one of two VR rooms. In one room, they received real chocolate M&Ms, whereas no M&Ms were administered in the other room. Following conditioning, a three-minute free-access test session occurred during which participants had unrestricted access to both rooms without reward. Results: Individuals who received nicotine demonstrated a CPP by spending significantly more time in the room previously paired with M&Ms compared to the unrewarded room (p = 0.04). Those who received placebo did not demonstrate a CPP (p > 0.05). Moreover, we observed no significant differences between treatment groups in terms of the amount of time spent in each virtual room. Conclusion: While nicotine seems to facilitate CPP expression for a virtual environment previously paired with chocolate food rewards, further characterization of the mechanism by which this occurs is needed.

Keywords:

• Classical conditioning
• human learning
• nicotine
• conditioned place preference

Acknowledgements

The authors thank Allison Arnista, Michelle Padua, Callista Love, Kyrstyn Jenkins, Robert Livoti, and Oghenenyerovwo Okifo for their assistance with data collection. We also thank Dr. Thomas Gould for his valuable and constructive guidance when interpreting data.

The dataset analyzed during this study is available from the corresponding author on reasonable request.

Disclosure statement

All authors state that there are no competing financial interests to disclose.

Additional information

Funding

This work was supported in part by a University of Connecticut Department of Psychological Sciences Undergraduate Research Grant and the Connecticut Institute for Brain and Cognitive Sciences.