Nucleus accumbens response to rewards and testosterone levels are related to alcohol use in adolescents and young adults

Abstract

During adolescence there is a normative increase in risk-taking behavior, which is reflected in, for example, increases in alcohol consumption. Prior research has demonstrated a link between testosterone and alcohol consumption, and between testosterone and neural responses to rewards. Yet, no study to date tested how testosterone levels and neural responses to rewards relate to and predict individual differences in alcohol use. The current study aimed to investigate this by assessing alcohol use, testosterone levels and neural responses to rewards in adolescents (12-17 years old) and young adults (18-26 years old). Participants were measured twice with a two-year interval between testing sessions. Cross-sectional analysis showed that at the second time point higher neural activity to rewards, but not testosterone levels, explained significant variance above age in reported alcohol use. Predictive analyses showed that, higher testosterone level at the first time point, but not neural activity to rewards at the first time point, was predictive of more alcohol use at the second time point. These results suggest that neural responses to rewards are correlated with current alcohol consumption, and that testosterone level is predictive of future alcohol consumption. These results are interpreted in the context of trajectory models of adolescent development.

Keywords: Adolescence; Alcohol; Nucleus accumbens; Risk-taking; fMRI.

Fig. 1

Example of a trial. On trial onset, participants were presented with a screen for 4000 ms indicating for whom they were playing (self, friend or antagonist) and how many coins could be won or lost. During this time, participants chose to play heads or tails by pressing the corresponding button. After a 1000 ms delay, trial outcome was presented for 1500 ms. Participants won when the computer randomly selected the same side of the coin as chosen by the participant.

Fig. 2

Whole brain activation at the first and second time point for win > lose for self and the anatomical nucleus accumbens (NAcc) region used for analyses. A similar figure has been published before in Braams et al. (2015).

Fig. 3

Raw data and best fitting regression lines for age and the average amount of glasses that participant report to drink on average per night (panels A and B), the total amount of glasses that participant report to have consumed last month (panel C and D), the total amount of glasses that participant report to have consumed in their lifetime (panels E and F), also see Table 3.

Fig. 4

Visual display of the predictive relationship between testosterone levels, values are log transformed, at the first time point and average number of glasses consumed per night at the second time point and the cross sectional relationship between nucleus accumbens activation, parameter estimates for win > lose when playing for self, and the average amount of glasses consumed per night at the second time point.