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Alcohol Clin Exp Res. 2018 Oct;42(10):2000-2010. doi: 10.1111/acer.13850. Epub 2018 Aug 28.

Distinctions in Alcohol-Induced Memory Impairment: A Mixed Methods Study of En Bloc Versus Fragmentary Blackouts.

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Department of Psychiatry , University of Missouri School of Medicine, Columbia, Missouri.
Department of Behavioral and Social Sciences , Center for Alcohol and Addiction Studies, Brown University School of Public Health, Providence, Rhode Island.



Blackouts-or memory loss for all or part of a drinking event-are reliable predictors of alcohol-related consequences. Studies suggest a distinction between en bloc (complete memory loss) and fragmentary (off-and-on memory loss) blackouts; however, research has not consistently differentiated between these 2 forms of blackout. This study aimed to validate the distinction between en bloc and fragmentary blackouts among young adults.


Data were collected using qualitative (Study 1) and quantitative (Study 2) research methods. Participants in both studies were college students with a history of alcohol-induced memory impairment. They were recruited using community advertisement (Study 1, N = 50, 56% female) and Qualtrics survey panels (Study 2, N = 350, 56% female). Study 1 participants engaged in 8 focus groups. Discussions were audio-recorded, transcribed verbatim, and coded using applied thematic analysis. Findings guided assessment of en bloc and fragmentary blackout in Study 2. In Study 2, a separate sample of participants completed an online survey assessing drinking behavior, alcohol-induced memory impairment, and theoretical correlates of en bloc and fragmentary blackouts.


Study 1 participants differentiated between en bloc and fragmentary blackouts (which they referred to as "blackouts" and "brownouts," respectively) based on duration and extent of memory loss. They indicated that blackouts occur along a continuum, with en bloc "blackouts" at the extreme. They also stated that the term "blackout drinking" does not always imply memory loss. Study 2 participants reported higher rates of "brownouts" (81%) than "blackouts" (54%). They reported less negative outcome expectancies and attitudes, greater personal approval, higher prevalence estimates, lower self-efficacy, and stronger intentions for "brownouts" than "blackouts" (p < 0.001). Women perceived "blackouts/brownouts" as more prevalent than men and reported lower intentions to experience "blackouts" (p < 0.005).


Young adults are more permissive of fragmentary than en bloc blackout. En bloc blackouts may be a target for future interventions.


Alcohol; Blackout; Gender; Memory; Predictors

[Available on 2019-10-01]

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