We assessed whether non-substance psychiatric representations of stage-based addiction phenotypes confer risk for progression of alcohol milestones and/or arise following these milestones. We leverage the Collaborative Study on the Genetics of Alcoholism (COGA) Prospective Study, a large (n = 3681), deeply pheno-typed, and prospectively assessed cohort of individuals aged 12–21 at wave 1 to examine prospective and bidirectional associations between stage-based phenotypes (i.e. externalizing, internalizing, and EF) and progression across alcohol milestones (i.e. first drink, first intoxication, first AUD symptom(s), first AUD diagnosis; Bucholz et al., 2017). We use psychopathology symptom onsets as proxies for stage-based phenotypes for several reasons: Patterns of comorbidity between AUD and externalizing and internalizing disorders parallel links between stages of alcohol involvement and the core constructs of impulsivity and negative affect, respectively, implicated in these disorders;Retrospectively reported onsets of such symptoms are carefully defined in this cohort, whereas continuous measures of impulsivity and negative affect may not be assessed before alcohol milestones;Whether distinct subtypes of internalizing and externalizing disorders are specifically and bidirectionally related to alcohol involvement in ways consistent with the stage-based model has
