Alcohol-Related Blackouts in College Students


Alcohol Medical Scholars Program


Jennifer E. Merrill, Ph.D.


Center for Alcohol & Addiction Studies

Brown University


Outline Draft:

I.  Introduction (SLIDE 2)

     A.  Definition of alcohol-related blackout (ARB)

         1. Memory loss for all or part of drinking episode

         2. Can actively engage in behaviors (e.g., walking, driving, conversation)

         3. But brain unable to create/retain memories

     B. Prevalent among college students (SLIDE 3)

          1. ~50% experience ARBs before or during college1-3

          2. 30% experience an ARB each year4

     C.   Blackouts are not benign (SLIDE 4)

           1. Associated with sexual assault

           2. ↑ risk of injury/emergency department care

     D. This lecture covers (SLIDE 5)

           1. Types/definitions and mechanisms of ARBs

           2. Prevalence of ARBs among college students

           3. ARB-associated harms

           4. Behavioral and individual-level risk factors

           5. How to address/avoid blackouts

     E. Case example (Jordyn) [HAVE A PICTURE] (SLIDE 6)

         1. Female, age 19, college sophomore

         2. Normal upbringing, light drinking in high school

         3. First ARB during freshmen orientation week of college

         4. Now experiences ARBs ~ once/mo

         5. What are the causes and consequences of her ARBs?              

II. Definitions and mechanisms of blackouts (SLIDE 7)

      A. 2 types (SLIDE 8)

           1. En bloc blackouts

               a. Inability to recall large portions of drinking episode

               b. Have a distinct onset


               c. Memory not formed; no memory to recall

           2. Fragmentary ARBs (“brownout”, “grayout”)

               a. Partial memory for drinking episode

               b. Ability to retrieve partial memory with cues

           3. ARB ≠ passing out (unwanted falling asleep and inability to engage) (SLIDE 9)

           4. Requires self-report; difficult to detect by others5,6

      B.  Biological mechanisms of memory (SLIDE 10)

           1. Model of memory formation, storage and retrieval7

               a. Info enters sensory memory (lasts a few seconds)

               b. Info transfers to short-term (ST) memory (encoding)

               c. ST memory lasts seconds to minutes (depending on whether info rehearsed)

               d. Info transfers from ST to long-term (LT) storage (encoding)

          2. How ARBs work (theoretically)8 (SLIDE 11)

               a. Alcohol interferes with transfer info from ST to LT storage

               b. If modest intoxication can still:

1’. Keep new info in ST storage if not distracted

                  2’. Retrieve info placed in LT storage prior to intoxication

              c. ARB when alcohol impairs info storage across longer delays

              d. Memory impairment as dose-related continuum (SLIDE 12)

                  1’. Mild impairments at lower doses

                  2’. Greater impairments at higher doses

                  3’. Jordyn (J) has en bloc ARB on heaviest drinking nights

                  4’. All ARB impairments same fundamental deficit (inability to transfer ST to LT)

III. Prevalence of ARBs (SLIDE 13)

       A. ~ 20% of young adult drinkers ever have ARB9,10 (SLIDE 14)

       B. College students have even higher rates

            1. ~ 30% report ARB each year4

            2. Among drinkers, 40% past-year

            3. ARBs > in 4 year college student drinkers (29%) than:

    a. 2 year college drinkers (13%)

    b. non-college drinking peers (14%)11

            4. Gender differences12 (SLIDE 15)

                 a. Males: 35% 1+ ARB over 55 weeks

                 b. Females: 48%

c. But no difference in some studies1,13-15

            5. Frequency (SLIDE 16)


a.       Not only prevalent, but recurrent for some12

1.’ Over 55 weeks, 9% 2 ARB

2.’ 2.5% each with 4, 5, or 6 ARB

                 b. Once every 5 drinking weeks in freshmen year16

IV. Additional harms associated with ARBs (SLIDE 17)

       A. ~ 50% with ARB hx have other problems during ARB3 (SLIDE 18)

          1. 33% insult someone

          2. 27% spend money unintentionally

       B. Compared to those who drink same amount w/out ARBs, students with 6+ past yr ARBs:

            1. 70% more likely treated in ER over 2 years13

            2. ~3x more likely to suffer alcohol-related injury over 2 years14

            3.  J: freshman year broke leg while intoxicated

       C. Sexual risks (heightened among women) (SLIDE 19)

            1. Men w/ recent ARB slightly (~50%) higher risk for unsafe, unplanned, regretted sex

2. Women w/ recent ARB have:

    a. 5x ↑ unsafe sex

    b. 5x↑ unplanned sex

    c. ~4x↑ regretted sex17

       D. Someone like J, with ARBs in past 6 mos. more likely also report11 (SLIDE 20)

            1. Hangovers (8x more likely)

            2. Arguing with friends (8x)

            3. Doing something regretted (10x)

            4. Academic problems

    a. Missing class (11.5x)

    b. Getting behind in school work (17x)

5. Seeing a doc for alcohol overdose (e.g., passed out, unable to be aroused) (144x)

       E. If frequent ARB 4th year, longer-term (1 year) outcomes include19  (SLIDE 21)

            1. Continued ARBs

2. ↑ Emotional and social alcohol consequences, e.g.: 

                      a. Had regrets, felt angry, felt worried


                  b. Felt rejected or hurt reputation


             3. ↑ quantity of alcohol consumed

             4. If J has ARB senior year, expect cont’d problems after graduation

V. Factors that ↑ ARB Risk (SLIDE 22)

       A. Reaching high blood alcohol concentrations (BAC) (SLIDE 23)

          1. What determines BAC?

a. Standard (STD) drink = 10 gm ethanol: e.g., 12 oz beer; 4 oz wine; 1 oz liquor

            b. 1 STD drink → BAC ~ .02 gm/100 ml

            c. Person metabolizes ~ 1 STD drink/hour

          2. Drinks to reach en bloc vs fragmentary (SLIDE 24)

a. En bloc: 50% probability at BAC 0.31 gm/100 ml blood20

            b. 18 STD in 2 hours ΰ BAC ~ .32 gm/100 ml

            c. Fragmentary ARB: 50% probability at BAC of .22

            d. ~ 12 STD drinks over 2 hours20

        3. But higher BACs also a function of

           a. Lower weight

            b. Female gender (women metabolize alcohol more slowly)

            c. So, may take J (100 lb female) much < 18 STD drinks

    B.  Rapid rate of ↑ in BAC → ↑ARB risk from: (SLIDE 25)

         1. Gulping drinks21

         2. Drinking on empty stomach21

         3. Shots of liquor vs beer or wine (more alcohol in less volume, faster)

         4. Starting drinking before social event (i.e., pregaming or prepartying)22

         5. Drinking games (e.g., drink as penalty for wrong answer)23

     C. Use of other drugs in combination w/ alcohol (SLIDE 26)

          1. Depressants like benzodiazepines (e.g., diazepam [Valium])

               a. Itself can ΰ severe memory impairment at high doses24,25

               b. Effects enhanced by alcohol26

               c. Combining ↑s likelihood of memory impairment

          2. THC (primary psychoactive compound in marijuana)

               a. W/ alcohol ΰ greater impairment than either alone27

               b. ↓ Awareness of intoxication when high ΰ more drinking

          3. Stimulants (e.g.,  coke ↓alcohol sedation; ΰ ↑ drinksΰ ↑ ARB

          4. J: ↑ ARBs when also uses marijuana, or drinks vodka w/caffeinated mixer

     D. Some personal characteristics ↑ risk (SLIDE 27)


          1. Biological characteristics

              a. Genetics

                 1’. Family history of alcohol problems

a’. Family hx of alc problems (FH+) 24% more likely ARB22

b’. Maternal FH+ ↑ risk as much as 2x1

c’. Despite “normal” upbringing, J’s dad treated for alcohol problems

     2’. Heritable component to experiencing ARBs28

           a.’ Heritability = % variation in trait due to genetic variation in population

           b’. 53% heritability for lifetime ARBs

             b. Low level of response (LR) to alcohol12 (SLIDE 28)

      1’. Low sensitivity per drink of  alcohol

      2’. Need more alcohol than most to get desired effect

      3’. Tend to drink more and more often

      4’. J describes not feeling any “buzz” after first 2 or 3 of drinks

              c. After alcohol ARB+ have ↓ brain activity on memory task29  (SLIDE 29)


              d. Race/ethnicity12

                  1’. Highest rates in European American students (like J)

                  2’. Lowest in Asian students

                  3’. Intermediate in Hispanic students

          2. Psychological and social correlates ARBs (SLIDE 30)

   a. Generally mirror risk factors for heavy drinking

               b. Sensation seeking (SS)/impulsivity30

                   1’. SS = seek novel, stimulating experiences to arousal

                   2’. Impulsivity = carelessness, lack of planning, disregard for consequences

               c. Earlier age of onset of alcohol use31

                   1.’ First drink at age 16 if ARB in college

                   2.’ First drink at 17 if no ARB in college

               d. Perceived peer behavior and attitudes favoring substance use (SLIDE 31)

                   1’. Higher estimated % of peers using alcohol, drugs, tobacco30

                   2’. Higher perceived peer alcohol use15

                   3’. Higher perceived peer approval of use15,32

                d. Alcohol outcome expectancies (AOEs) (SLIDE 32)

                   1’. AOEs = Anticipated outcomes (cognitive, affective, behavioral) of alcohol use

                        a’. Negative (e.g., I would have difficulty thinking)

                       b’. Positive (e.g., I would be friendly)

                   2’. Stronger positive AOEs associated w/ ARB33,34

                  e. Drinking motives (SLIDE 33)

                   1’. Drinking to ↑ positive mood associated w/:

                        a’. Concurrent ARBs35

                        b’. ARBs 1 year later36

                        c. ↑ ARBs over 2 years15  

                   2’. Drinking to get drunk: 7x more likely report ARB37  

               f. Jordyn: (SLIDE 35)

                  1’. Acts without considering consequences (impulsivity)

      2’. First drink age 14

      3’. Friends drink heavily and approve of ARBs

      4’. Drinks to “get high” and expects alcohol makes her feel good

VI. How to address problem of ARBs (SLIDE 36)

      A. Screen all patients (including teens) for ARBs (SLIDE 37)

         1. Many MDs don’t ask or counsel re: alcohol harms38,39

         2. E.g., “Have you forgotten a part of evening while drinking alcohol in past year?”

         3. Affirmative response ΰ follow-up questions about ARB frequency

              a. Repeated ARBs associated with worse outcomes19

              b. Refer for treatment if needed (worth considering for J)

      B. Teach anyone with ARBs to ↓ risk: (SLIDE 38)

          1. Avoid liquors (e.g., vodka); use lower % alcohol  (e.g., beer)

          2. Space out drinks over time

          3. Eat before/during drinking

          3. Avoid drinking prior to main social event (e.g., games, parties)

     C. Address perceptions of ARBs (SLIDE 39)

          1. Consider extent to which student perceives ARB negatively

              a. Students may not find ARBs bothersome40,41

  b. If ARB not subjectively neg, ↑ perceived risk via education:

      1'. ARB = reaching BACs consistent w/ severe brain impairments29,42

     2’. Remind J, this level dysfunction ΰ wide range of neg outcomes                                

          2. Help change attitudes (if drinker believes everyone has/approves of ARBs) (SLIDE 40)

              a. In fact, only 30% (not 100%) of college students have ARB

  b. Majority of students really think ARBs are bad

VII. Conclusion (take away points) (SLIDE 42)

        A. ARBs are common among college student drinkers

        B. ARBs are associated with negative outcomes (acute, long-term)

        C. ARB risks ↑ with specific styles of drinking and risk factors

        D. They are avoidable and should be addressed by health providers



1.            Marino EN, Fromme K. Alcohol-induced blackouts and maternal family history of problematic alcohol use. Addictive Behaviors. 2015;45:201-206.

2.            Perkins HW. Surveying the damage: A review of research on consequences of alcohol misuse in college populations. Journal of Studies on Alcohol. 2002;SUPPL14:91-100.

3.            White AM, Jamieson-Drake DW, Swartzwelder HS. Prevalence and Correlates of Alcohol-Induced Blackouts Among College Students: Results of an E-Mail Survey. Journal of American College Health. 2002;51(3):117-119, 122-131.

4.            American College Health Association. American College Health Association-National College Health Assessment II: Reference Group Executive Summary Spring 2012. Hanover, MD: American College Health Association; 2012.

5.            Goodwin DW. Alcohol amnesia. Addiction. 1995;90(3):315-317.

6.            Pressman MR, Caudill DS. Alcohol-induced blackout as a criminal defense or mitigating factor: an evidence-based review and admissibility as scientific evidence. Journal of forensic sciences. Jul 2013;58(4):932-940.

7.            Atkinson RC, Shiffrin RM. Human memory: A proposed system and its control processes. In: Spence KW, Spence JT, eds. The psychology of learning and motivation. New York: Academic Press; 1968:89-195.

8.            White AM. What Happened? Alcohol, Memory Blackouts, and the Brain. Alcohol Research & Health. 2003;27(2):186-196.

9.            Jennison KM, Johnson KA. Drinking-induced blackouts among young adults: results from a national longitudinal study. The International journal of the addictions. Jan 1994;29(1):23-51.

10.          White HR, Ray AE. Differential evaluations of alcohol-related consequences among emerging adults. Prevention Science. 2013.

11.          Hingson R, Zha W, Simons-Morton B, White A. Alcohol-Induced Blackouts as Predictors of Other Drinking Related Harms Among Emerging Young Adults. Alcoholism: Clinical and Experimental Research. 2016;40(4):776-784.

12.          Schuckit MA, Smith TL, Goncalves PD, Anthenelli R. Alcohol-related blackouts across 55 weeks of college: Effects of European-American ethnicity, female sex, and low level of response to alcohol. Drug and alcohol dependence. Dec 1 2016;169:163-170.

13.          Mundt MP, Zakletskaia LI. Prevention for college students who suffer alcohol-induced blackouts could deter high-cost emergency department visits. Health affairs (Project Hope). Apr 2012;31(4):863-870.

14.          Mundt MP, Zakletskaia LI, Brown DD, Fleming MF. Alcohol-induced memory blackouts as an indicator of injury risk among college drinkers. Injury Prevention. 2012;18(1):44-49.

15.          Merrill JE, Treloar H, Fernandez AC, Monnig MA, Jackson KM, Barnett NP. Latent growth classes of alcohol-related blackouts over the first 2 years of college. Psychology of addictive behaviors : journal of the Society of Psychologists in Addictive Behaviors. Dec 2016;30(8):827-837.

16.          Barnett NP, Clerkin EM, Wood M, et al. Description and predictors of positive and negative alcohol-related consequences in the first year of college. Journal of Studies on Alcohol and Drugs. 2014;75(1):103-114.

17.          Haas AL, Barthel JM, Taylor S. Sex and Drugs and Starting School: Differences in Precollege Alcohol-Related Sexual Risk Taking by Gender and Recent Blackout Activity. Journal of sex research. Jul-Aug 2017;54(6):741-751.

18.          Valenstein-Mah H, Larimer M, Zoellner L, Kaysen D. Blackout Drinking Predicts Sexual Revictimization in a College Sample of Binge-Drinking Women. Journal of traumatic stress. Oct 2015;28(5):484-488.

19.          Wilhite ER, Fromme K. Alcohol-Induced Blackouts and Other Negative Outcomes During the Transition Out of College. Journal of Studies on Alcohol and Drugs. 2015/07/01 2015;76(4):516-524.

20.          Perry PJ, Argo TR, Barnett MJ, et al. The association of alcohol-induced blackouts and grayouts to blood alcohol concentrations. Journal of forensic sciences. 2006;51(4):896-899.

21.          Goodwin DW, Crane JB, Guze SB. Phenomenological aspects of the alcoholic 'blackout.'. The British Journal of Psychiatry. 1969;115(526):1033-1038.

22.          LaBrie JW, Hummer J, Kenney S, Lac A, Pedersen E. Identifying factors that increase the likelihood for alcohol-induced blackouts in the prepartying context. Substance Use & Misuse. 2011;46(8):992-1002.

23.          Ray AE, Stapleton J, Turrisi R, Mun EY. Drinking game play among first-year college student drinkers: An event-specific analysis of the risk for alcohol use and problems. American Journal on Drug and Alcohol Abuse. 2014;40(5):353-358.

24.          White AM, Simson PE, Best PJ. Comparison between the effects of ethanol and diazepam on spatial working memory in the rat. Psychopharmacology. Oct 1997;133(3):256-261.

25.          Saum CA, Inciardi JA. Rohypnol Misuse in the United States. Substance Use & Misuse. 1997/01/01 1997;32(6):723-731.

26.          Silvers JM, Tokunaga S, Berry RB, White AM, Matthews DB. Impairments in spatial learning and memory: ethanol, allopregnanolone, and the hippocampus. Brain research. Brain research reviews. Dec 2003;43(3):275-284.

27.          Ciccocioppo R, Antonelli L, Biondini M, Perfumi M, Pompei P, Massi M. Memory impairment following combined exposure to Δ9-tetrahydrocannabinol and ethanol in rats. European Journal of Pharmacology. 2002/08/09/ 2002;449(3):245-252.

28.          Nelson EC, Heath AC, Bucholz KK, et al. Genetic epidemiology of alcohol-induced blackouts. Arch Gen Psychiatry. Mar 2004;61(3):257-263.

29.          Wetherill RR, Schnyer DM, Fromme K. Acute Alcohol Effects on Contextual Memory BOLD Response: Differences Based on Fragmentary Blackout History. Alcoholism, Clinical and Experimental Research. 03/15 2012;36(6):607-617.

30.          Schuckit MA, Smith TL, Heron J, et al. Latent trajectory classes for alcohol-related blackouts from age 15 to 19 in ALSPAC. Alcohol Clin Exp Res. Jan 2015;39(1):108-116.

31.          Marino EN, Fromme K. Early Onset Drinking Predicts Greater Level But Not Growth of Alcohol-Induced Blackouts Beyond the Effect of Binge Drinking During Emerging Adulthood. Alcoholism: Clinical and Experimental Research. 2016;40(3):599-605.

32.          Brett EI, Leavens EL, Miller MB, Lombardi N, Leffingwell TR. Normative perceptions of alcohol-related consequences among college students. Addict Behav. Jul 2016;58:16-20.

33.          Buelow G, Harbin J. The influence of blackouts on alcohol use expectancies. Journal of Alcohol and Drug Education. 1996;42:25-34.

34.          Hartzler B, Fromme K. Fragmentary blackouts: their etiology and effect on alcohol expectancies. Alcohol Clin Exp Res. Apr 2003;27(4):628-637.

35.          Merrill JE, Read JP. Motivational pathways to unique types of alcohol consequences. Psychology of Addictive Behaviors. 2010;24(4):705-711.

36.          Merrill JE, Wardell JD, Read JP. Drinking motives in the prospective prediction of unique alcohol-related consequences in college students. Journal of Studies on Alcohol and Drugs. 2014;75(1):93-102.

37.          Boekeloo BO, Novik MG, Bush E. DRINKING TO GET DRUNK AMONG INCOMING FRESHMEN COLLEGE STUDENTS. American journal of health education / American Alliance for Health, Physical Education, Recreation, and Dance. 01/23 2011;42(2):88-95.

38.          Hingson R, Zha W, White A, Simons-Morton B. Screening and brief counseling among young adults: comparison of college students, community college students, and persons not in school. Addiction Science & Clinical Practice. 09/24 2015;10(Suppl 2):P7-P7.

39.          Hingson RW, Heeren T, Edwards EM, Saitz R. Young Adults at Risk for Excess Alcohol Consumption Are Often Not Asked or Counseled About Drinking Alcohol. Journal of General Internal Medicine. 09/21 2012;27(2):179-184.

40.          Merrill JE, Read JP, Barnett NP. The way one thinks affects the way one drinks: Subjective evaluations of alcohol consequences predict subsequent change in drinking behavior. Psychology of Addictive Behaviors. 2013;27(1):42-51.

41.          Barnett NP, Merrill JE, Kahler CW, Colby SM. Negative evaluations of negative alcohol consequences lead to subsequent reductions in alcohol use. Psychology of addictive behaviors : journal of the Society of Psychologists in Addictive Behaviors. Dec 2015;29(4):992-1002.

42.          Bjork JM, Gilman JM. The effects of acute alcohol administration on the human brain: Insights from neuroimaging. Neuropharmacology. 08/23 2014;0:101-110.