Alcohol Effects on Adolescent Brain- Dr[1]. Winter

8/4/2019 Alcohol Effects on Adolescent Brain- Dr[1]. Winter

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BRAIN RESEARCHTHE EFFECTS OF ALCOHOL ON THE ADOLESCENT BRAIN

Ken Winters, Ph.D.Department of PsychiatryUniversity of [email protected]

CSAPs Western CAPT

Audio Teleconference

March 18, 2004
mailto:[email protected]:[email protected]


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1. Developmental Issues


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Alcohol Use

Youth alcohol use occurs on a continuum

Most youth have used some alcohol

Alcohol Use by Youth

7 millionteens bingedrink at leastonce a month


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Trends in prevalence of drugs for 12th graders: 1994 to 200130-Day

Year Alcohol %

1994 50.1

1995 51.3

1996 50.8

1997 52.7

1998 52.0

1999 51.0

2000 50.0

2001 49.8

MTFS, 1975-2001


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Long-Term, Heavy Use of Alcohol

Significant shrinking of the brain

50% - 75% show cognitive impairment

Effects remain even after detoxification &abstinence

Alcohol dementia is 2nd-leading cause of adultdementia


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2. Adolescence and t

Brain



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The Adolescent Brain is StillDevelopingDuring adolescence, the brain is

undergoing dramatic transformations

In some brain regions, over 50 % of

neuronal connections are lost

Some new connections are formed

Net effect is pruning (a loss of neurons)


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Adolescent Brain ChangesThese brain changes are

relevant to adolescentbehavior

Prefrontal cortex (PFC) ispruned; not fullydeveloped until mid-20s

Amygdala (and n.a.) showless pruning and tend todominate the PFC

judgment

rewardsystem

amygdala

nucleusaccumbens

prefrontal

cortex


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This imbalance leads to... planned thinking impulsiveness self-control risk-taking

more hot talking, less cool talking

PFC

amygdala

I liketo usedrugs!

!


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PFC

amygdala

In the presence of stress

I hateschool; I am

going toskip classes

and getdrunk


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PFCamygdala

GOOD NEWS!The pruning of the PFC neuronsproduces a more efficient PFC byyoung adulthood

I amplanning forthe future


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Brain

3. Brain and Alcohol


Is addiction abrain disorder


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From Oops to Dependence


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Oops PhenomenonFirst use to FEEL GOOD

Some continue tocompulsively use becauseof the reinforcing effects(e.g., to FEEL NORMAL)

Changes occur in the

reward system thatpromote continued use


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Reward SystemThe reward system is

responsible for seekingnatural rewards that

have survival valueseeking food, water,

sex, and nurturing

Dopamine is this

systems primaryneurotransmitter

reward


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Drugs Hijack the BrainsReward Circuitry Immediate effect of drug use is an increase

in dopamine

Continued use of drugs reduces the brainsdopamine production.

Because dopamine is part of the rewardsystem, the brain is fooled that the drughas survival value for the organism.

The reward system responds with drugseeking behaviors

Craving occurs and, eventually, dependence.

reward


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EvidenceAnimal Studies:

electrodes attached to Reward Circuit

animals press lever to receive stimuli to brain

they continue until collapse from exhaustion

Behavioral Genetics Studies:heredity plays a role

identical twins: > chance of becoming alcoholics than fraternal twins

adoptive children of alcoholics: > chance of becoming alcoholic;

even true when raised by non-alcoholic parents

further research needed by gender


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Brain

3. Brain and Alcohol

4. Youth, Brainand Alcohol

Are adolescentsmore susceptible toalcohol than adults?


Is addiction abrain disorder


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Are adolescents more susceptibleto alcohol than adults?Adult studies suggest

that the areas of theadolescent brain thatare remodeled are

sensitive to theeffects of alcohol

Difficult scientifically and

ethically to study adolescentsensitivity to alcohol

amygdala

nucleusaccumbens

prefrontalcortex


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Are adolescents more susceptibleto alcohol than adults?

Animal models can be easily used toexplore this issue

Role of psychosocial factors can not bestudied


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Are adolescents more susceptibleto alcohol than adults?

1. Adolescent rats are less sensitive to

effects of intoxication and less sensitiveto the hangover that follows use


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Are adolescents more susceptibleto alcohol than adults?2. Adolescent rats are more sensitive

to the social disinhibition inducedby alcohol use

Wanna look

for some cheesewith me?

Sure!


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Are adolescents more susceptibleto alcohol than adults?3. Adolescent drunk rats perform

worse on memory tasks than adultdrunk rats

Ugh??

disrupts the hippocampus

brain damage in the PRF

converts

informationto memory

planned

thinking


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Supporting Human Studies1. Reduced sensitivity to

intoxication

3. Greater adverse effectsto cognitive functioning


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Survey Data Suggest that AdolescentsAre More Sensitive to Alcohol

14

8

26 2430 32

0

20

40

60

80

100

8th Graders 10th Graders 12th Graders

5+ drinks in row, past 2 wee

Been drunk past month

Monitoring the Future, 2001


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Alcohols Effects Adolescents with a history of extensive

use.

Hippocampus (50%)

brain activity during memory tasks

brain activation when shown alcohol images

convertsinformatio

n tomemory

triggerfor

relapse

(Brown, 2002; Wuethrich, 2001


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Are adolescents more susceptibleto alcohol than adults?4. Hyperexcitability issue


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Are adolescents more susceptibleto alcohol than adults?4. Hyperexcitability issue

Alcohol relieves hyperexcitability state

Relief is temporary; continued seeking of

alcohol is reinforced

Hyperexcitability is a key characteristic ofconduct disorders, ADHD & other impulsivebehaviors

Found in non-alcoholic relatives - suggests

inheritance of brain wave patterns


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Are adolescents more susceptibleto alcohol than adults?1 Reduced sensitivity to intoxication

2 Increased sensitivity to social

disinhibitions3 Greater adverse effects to cognitive

functioning

4 Medicates excitability

Most certainly YES


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References Leshner A. Oops. How casual drug use leads to addiction. National

Institute on Drug Abuse web site:www.drugabuse.gov/Published_Articles/Oops.html

September, 2000.

National Institute on Alcohol Abuse and Alcoholism. Imaging andAlcoholism: A Window on the Brain.

Alcohol AlertNo. 47, April 2000. National Institute on Alcohol Abuse and Alcoholism. Tenth Special

Report to the U.S. Congress on Alcohol and Health, NIH Pub. No. 00-1583, 2000.

National Institute on drug Abuse. Principles of drug addictiontreatment: A research-based guide.

No. 99-4180, 1999.


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Thank You!

Documents

Alcohol Effects on Adolescent Brain- Dr[1]. Winter