Alcohol-Related Blackouts in College Students
Alcohol Medical Scholars Program
Jennifer E. Merrill, Ph.D.
Center for Alcohol & Addiction Studies
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 contd 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
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, Js 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)
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
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 dont 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
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