Acute Caffeine Influences the Reinforcing Value of Soda
Authors: Ziegler Amanda M , Crandall Amanda , Graczyk Adam M , Andrle Nicole , Ewing Brittany , Hussain Sarah , Temple Jennifer L 
Published: November 2023

ObjectiveThe purpose of this study was to determine whether sex and pubertal phase differences in the relative reinforcing value (RRV) of caffeinated beverages.MethodsMale and female youth, aged 8–9 and 15–17, were recruited and categorized as pre or post pubertal. Each participant was given a taste test of novel soda flavors, assigned to a flavor, and then exposed to a 6‐visit, within‐subjects exposure paradigm. Visits 1 & 2 were exposure visits and 3 was a test visit, followed a week later by visits 4 & 5 as exposure visits and 6 as a test visit. Each participant was exposed to a dose in their assigned beverage flavor containing a placebo (0 mg/kg) and low dose (1mg/kg caffeine) during one week and placebo (0 mg/kg) and high dose (2mg/kg caffeine) during another week. Visits 3 and 6 measured the RRV of the two most recently exposed doses. Each beverage was also rated for liking, novelty, and other taste preferences after each exposure. This study was approved by the University at Buffalo Social and Behavioral Institutional Review Board.ResultsWe found that, for the week where participants consumed the high dose of caffeine (2 mg/kg), there was no difference in the RRV between caffeine and placebo. For the week where participants were exposed to the low dose of caffeine (1 mg/kg), there was a significant main effect of pubertal phase on responding (F(1, 44) = 4.3; p = 0.044), with prepubertal participants responding more than post‐pubertal participants. We also found an interaction between caffeine exposure and pubertal phase (F(1, 44) = 7.8; p < 0.008), and an interaction among pubertal phase, schedules of reinforcement, and caffeine exposure (F(5, 220) = 4.99; p < 0.0001). Post hoc analyses revealed that the pre‐pubertal participants had a lower RRV for caffeine than placebo, but the post‐pubertal participants had higher RRV for caffeine compared with placebo. When we examined hedonic and taste ratings of the beverages, we found that liking for beverages containing the high dose of caffeine (2 mg/kg) were rated lower than the low dose (1 mg/kg) and placebo (F(3, 129) = 7.6; p < 0.0001). Beverages containing the high dose of caffeine were rated as the most novel and those containing the low dose of caffeine as least novel, with placebo beverages being intermediate (F(3, 129) = 3.6; p = 0.016). Beverages containing the high dose of caffeine were rated as more bitter than the other beverages (F(3, 129) = 4.4; p = 0.005), but there were no differences in sweet, sour, or acidic ratings as a function of caffeine dose (all p > 0.05)ConclusionsWhen taken together, this study suggests that a single, acute exposure to caffeine can alter the reinforcing value of beverages with which it is paired and that these effects differ as a function of caffeine dose and pubertal phase. In addition, hedonic ratings for the beverages were not associated with the amount of work performed for these beverages, with the least liked beverage (2 mg/kg caffeine) supporting the second most responding. When taken together, these studies suggests that even very brief exposure to caffeine containing beverages can alter their reinforcing properties and that post‐pubertal children may be more susceptible to these effects.Support or Funding InformationThis study was supported by a R01‐DA030386 to JLT.