Trajectories of Alcohol Initiation and Use During Adolescence: The Role of Stress and Amygdala Reactivity.

OBJECTIVE: Early alcohol use initiation predicts onset of alcohol use disorders in adulthood. However, little is known about developmental trajectories of alcohol use initiation and their putative biological and environmental correlates.
METHOD: Adolescents (N = 330) with high or low familial loading for depression were assessed annually for up to 6 years. Data were collected assessing affective symptoms, alcohol use, and stress at each assessment. Adolescents also participated in a functional magnetic resonance imaging protocol that included measurement of threat-related amygdala and reward-related ventral striatum activity.
RESULTS: Latent class analyses identified 2 trajectories of alcohol use initiation. Early initiators (n = 32) reported greater baseline alcohol use and rate of change of use compared with late initiators and/or current abstainers (n = 298). Early initiators reported higher baseline levels of stressful life events (p = .001) and exhibited higher amygdala (p = .001) but not ventral striatum activity compared with late initiators. Early initiators were 15.3 times more likely to have a full drink (p < .0001), 9.1 times more likely to experience intoxication (p < .0001), and 6.7 times more likely to develop an alcohol use disorder by 19 years of age compared with late initiators (p = .003).
CONCLUSION: Adolescents on a trajectory of early alcohol use initiation have higher levels of stress, have increased threat-related amygdala activity, are more likely to consume a full standard alcoholic drink, are more likely to experience early intoxication, and are at a heightened risk for the onset of an alcohol use disorder.