Longitudinal Changes in Adolescent Risk-Taking: A Comprehensive Study of Neural Responses to Rewards, Pubertal Development, and Risk-Taking Behavior

TLDR

Adolescence is marked by heightened risk‑taking linked to an overactive reward system, and longitudinal studies are essential to detect individual changes in brain–behavior relationships. The study aimed to characterize age‑related trajectories of nucleus accumbens reward responses and to determine whether pubertal development and risk‑taking behavior predict longitudinal changes in this activity. Participants (n = 299 at baseline, 254 at follow‑up, ages 8–27) underwent fMRI reward tasks, pubertal assessments, BART, and BAS questionnaires at two time points separated by two years. Results revealed a quadratic, adolescent‑peak trajectory of nucleus accumbens reward activity that mirrored a similar pattern in laboratory risk‑taking, and changes in this activity were linked to shifts in testosterone levels and reward‑sensitivity.

Abstract

Prior studies have highlighted adolescence as a period of increased risk-taking, which is postulated to result from an overactive reward system in the brain. Longitudinal studies are pivotal for testing these brain-behavior relations because individual slopes are more sensitive for detecting change. The aim of the current study was twofold: (1) to test patterns of age-related change (i.e., linear, quadratic, and cubic) in activity in the nucleus accumbens, a key reward region in the brain, in relation to change in puberty (self-report and testosterone levels), laboratory risk-taking and self-reported risk-taking tendency; and (2) to test whether individual differences in pubertal development and risk-taking behavior were contributors to longitudinal change in nucleus accumbens activity. We included 299 human participants at the first time point and 254 participants at the second time point, ranging between ages 8–27 years, time points were separated by a 2 year interval. Neural responses to rewards, pubertal development (self-report and testosterone levels), laboratory risk-taking (balloon analog risk task; BART), and self-reported risk-taking tendency (Behavior Inhibition System/Behavior Activation System questionnaire) were collected at both time points. The longitudinal analyses confirmed the quadratic age pattern for nucleus accumbens activity to rewards (peaking in adolescence), and the same quadratic pattern was found for laboratory risk-taking (BART). Nucleus accumbens activity change was further related to change in testosterone and self-reported reward-sensitivity (BAS Drive). Thus, this longitudinal analysis provides new insight in risk-taking and reward sensitivity in adolescence: (1) confirming an adolescent peak in nucleus accumbens activity, and (2) underlining a critical role for pubertal hormones and individual differences in risk-taking tendency.