BRAIN RESEARCH THE EFFECTS OF ALCOHOL ON THE ADOLESCENT BRAIN

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BRAIN RESEARCHTHE EFFECTS OF ALCOHOL ON THE
ADOLESCENT BRAIN
Ken Winters, Ph.D. Department of
Psychiatry University of Minnesota winte001_at_umn.ed
u CSAPs Western CAPT Audio Teleconference Marc
h 18, 2004
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1. Developmental Issues
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Alcohol Use by Youth
Youth alcohol use occurs on a continuum Most
youth have used some alcohol
7 million teens binge drink at least once a month
Alcohol Use
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Trends in prevalence of drugs for 12th graders
1994 to 2001
30-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 adult
  dementia

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1. Developmental Issues
2. Adolescence and the Brain
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The Adolescent Brain is Still Developing

• During 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 Changes
prefrontal cortex

• These brain changes are relevant to adolescent
  behavior
• Prefrontal cortex (PFC) is pruned not fully
  developed until mid-20s
• Amygdala (and n.a.) show less pruning and tend to
  dominate the PFC

amygdala
nucleus accumbens
judgment
reward system
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This imbalance leads to... ? planned thinking
? impulsiveness ? self-control ?
risk-takingmore hot talking, less cool
talking
I like to use drugs!!
PFC
amygdala
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In the presence of stress
I hate school I am going to skip classes and get
drunk
PFC
amygdala
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GOOD NEWS! The pruning of the PFC neurons
produces a more efficient PFC by young adulthood
I am planning for the future
amygdala
PFC
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1. Developmental Issues
2. Adolescence and the Brain
3. Brain and Alcohol
Is addiction a brain disorder?
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• From Oops to Dependence

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Oops Phenomenon

• First use to FEEL GOOD
• Some continue to compulsively use because of the
  reinforcing effects (e.g., to FEEL NORMAL)
• Changes occur in the reward system that promote
  continued use

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Reward System

• The reward system is responsible for seeking
  natural rewards that have survival value
• seeking food, water, sex, and nurturing
• Dopamine is this systems primary neurotransmitter

reward
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Drugs Hijack the Brains Reward Circuitry

• Immediate effect of drug use is an increase in
  dopamine
• Continued use of drugs reduces the brains
  dopamine production.
• Because dopamine is part of the reward system,
  the brain is fooled that the drug has survival
  value for the organism.
• The reward system responds with drug seeking
  behaviors
• Craving occurs and, eventually, dependence.

reward
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Evidence

• Animal 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 gt chance of becoming alcoholics
  than fraternal twins
• adoptive children of alcoholics gt chance of
  becoming alcoholic
• even true when raised by non-alcoholic parents
• further research needed by gender

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1. Developmental Issues
2. Adolescence and the Brain
4. Youth, Brain and Alcohol
3. Brain and Alcohol
Are adolescents more susceptible to alcohol than
adults?
Is addiction a brain disorder?
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Are adolescents more susceptible to alcohol than
adults?

• Adult studies suggest that the areas of the
  adolescent brain that are remodeled are sensitive
  to the effects of alcohol

prefrontal cortex
amygdala
nucleus accumbens
Difficult scientifically and ethically to study
adolescent sensitivity to alcohol
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Are adolescents more susceptible to alcohol than
adults?

• Animal models can be easily used to explore this
  issue
• Role of psychosocial factors can not be studied

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Are adolescents more susceptible to alcohol than
adults?
1. Adolescent rats are less sensitive to effects
of intoxication and less sensitive to the
hangover that follows use
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Are adolescents more susceptible to alcohol than
adults?

• 2. Adolescent rats are more sensitive to the
  social disinhibition induced by alcohol use

Sure!
Wanna look for some cheese with me?
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Are adolescents more susceptible to alcohol than
adults?

• 3. Adolescent drunk rats perform worse on memory
  tasks than adult drunk rats

Ugh??
converts information to memory
disrupts the hippocampus brain damage in the PRF
planned thinking
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Supporting Human Studies
1. Reduced sensitivity to intoxication 3.
Greater adverse effects to cognitive functioning
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Survey Data Suggest that Adolescents Are More
Sensitive to Alcohol
Monitoring the Future, 2001
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Alcohols Effects
(Brown, 2002 Wuethrich, 2001)

• Adolescents with a history of extensive use.
• Hippocampus (50)
• brain activity during memory tasks
• brain activation when shown alcohol images

converts information to memory
trigger for relapse
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Are adolescents more susceptible to alcohol than
adults?

• Hyperexcitability issue

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Are adolescents more susceptible to alcohol than
adults?

• 4. Hyperexcitability issue
• Alcohol relieves hyperexcitability state
• Relief is temporary continued seeking of
  alcohol is reinforced
• Hyperexcitability is a key characteristic of
  conduct disorders, ADHD other impulsive
  behaviors
• Found in non-alcoholic relatives - suggests
  inheritance of brain wave patterns

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Are adolescents more susceptible to alcohol than
adults?
Most certainly YES

• Reduced sensitivity to intoxication
• Increased sensitivity to social disinhibitions
• Greater adverse effects to cognitive functioning
• Medicates excitability

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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.ht
  ml
• September, 2000.
• National Institute on Alcohol Abuse and
  Alcoholism. Imaging and Alcoholism A Window on
  the Brain.
• Alcohol Alert No. 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 addiction treatment A research-based guide.
  
• No. 99-4180, 1999.

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Thank You!