In the current phase of CSDP, participants were invited back between their fifth and sixth year of the study to participate in two re-examination laboratory sessions. The goal was to conduct empirical tests of the neurobiological theories of alcohol adaptations underlying the propensity to develop addiction. We examined whether the alcohol response differences observed at initial testing persisted or changed in heavy versus light drinkers, and whether the degree of change related to trajectories of AUD progression among the heavy drinkers. Tolerance theory would be supported if the heaviest drinkers over time showed an overall reduced alcohol response at re-examination compared with initial testing, whereas sensitization would be supported if the heaviest drinkers showed higher stimulant responses. The allostasis model’s early phase of addiction, which may most closely match a five-year interval in young adults, would be supported if alcohol reward sensitivity was maintained, and the later stage would be supported if reward sensitivity was diminished. Finally, increases over time in alcohol wanting would support the incentive-sensitization theory.
