Nicotine Facilitation of Conditioned Place Preference to Food Reward in Humans.

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. 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. 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 ( = 0.04). Those who received placebo did not demonstrate a CPP ( > 0.05). Moreover, we observed no significant differences between treatment groups in terms of the amount of time spent in each virtual room. 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.