Validation of the alcohol induced blackout measure-2 (ABOM-2) among young adults who experience blackout.

Memory loss from alcohol ("blackout") is common among young adults who drink and associated with significant alcohol-related harm. Despite longstanding evidence distinguishing fragmentary (transient) and en bloc (permanent) blackouts, a measure distinguishing these two forms of blackout (the Alcohol-Induced Blackout Measure-2 [ABOM-2]) was only recently developed and has not been psychometrically evaluated among young adults with a history of alcohol-induced blackouts. The present study evaluated the psychometric properties of the ABOM-2, particularly its longitudinal measurement invariance and prospective predictive validity, among 169 heavy-drinking young adults (ages 18-30) with a history of blackout. Confirmatory factor analyses at baseline (T1) and one-month follow-up (T2) supported previous research showing the ABOM-2 items are best represented by two correlated factors. Both factors, en bloc and fragmentary, demonstrated convergent validity, showing significant associations with hazardous drinking, alcohol consumption, and alcohol-related consequences. In concurrent convergent and prospective predictive regression models that accounted for relevant covariates and included both types of blackouts, en bloc (but not fragmentary) blackouts significantly predicted hazardous drinking, alcohol consumption, and consequences across time. Longitudinal measurement invariance testing provided evidence for configural, metric, and scalar invariance across T1 and T2, supporting the measurement equivalence of ABOM-2 over time. Findings reinforce the distinction between en bloc and fragmentary blackouts, support the convergent and predictive validity of the ABOM-2, and highlight the clinical and research utility of the ABOM-2 as a reliable tool for assessing blackout across time. En bloc blackouts, in particular, serve as a robust marker of alcohol-related risk among young adults.