winters brain 2004
TRANSCRIPT
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Effects of Drugs of Abuse onthe Developing BrainKen Winters, Ph.D.
Collaborating Investigator,Treatment Research
Institute
Professor, Department ofPsychiatry, University ofMinnesota
The Downtown Club of
mailto:[email protected]:[email protected]:[email protected]:[email protected]:[email protected] -
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Overview
Scientific study of braindevelopment can help usunderstand adolescent behavior
risk-taking and poor judgment
vulnerability to drug abuse
Relevance to parenting,
prevention and treatment
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Keep in mind..
The research on neuro- development isin the early stages
Many key human studies on youth cannot be conducted because of ethicalconsiderations
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Suggested Readings
www.thebrain.mcgill.ca/flash/index_d.html#Dubuc, B. (2004). The brain from top to bottom
www.drugabuse.gov/Published_Articles/Leshner A. (2000). Oops. How casual drug use leads to addiction. National Institute on
Drug Abuse, September, 2000.
Why do they act that way? : A survival guide to the adolescent brain for you and
your teenWalsh, D. (2004). NY: Simon & Schuster.
What makes teens tick?Wallis, C. (May 10, 2004). NY: Time magazine.
The adolescent brain and college drinker: Biological basis of propensity to use
and misuse alcohol.Spear, L. (2002). Journal of Studies on Alcohol, 14, pp. 71-81.
http://www.thebrain.mcgill.ca/flash/index_d.htmlhttp://www.thebrain.mcgill.ca/flash/index_d.htmlhttp://www.thebrain.mcgill.ca/flash/index_d.html -
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Some Background
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What is adolescence?
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Grade Alcohol % Marijuana % Any Illicit %
8 20 8 10
10 35 18 21
12 49 22 25
Substance Use by Youth - Prior Month2002(Monitoring the Futures, 2003)
Substance Abuse/Dependence ratesvary:
3-15%
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Can Addiction be Prevented by
Delaying Drug Use Onset?
Every year use of asubstance is delayed, the
risk of developing asubstance use disorder isreduced.
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Percentages of Past Year Alcohol Dependence or
Abuse Among Adults Aged 21 or Older, by Age of
First Use (SAMHSA, 2004)
1615
9
4.22.6
0
5
10
15
20
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During late childhood, neurons get bushier andincrease in the number of connections.
At about age 11 in girls and age 12 in boys,this thickening undergoes pruning.
At the same time, the myelin sheaths that
encase nerve cells thicken. Myelin sheaths are like insulation on a wire; they make
nerve cell transmissions faster and more efficient
Net effect when complete is faster, yet fewer,connections in the brain.
Construction Ahead
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Construction Ahead
motivation
emotion
judgment
cerebellum
amygdal
a
nucleusaccumbens
Pruning occurs in stages, from back of the
brain to the front
prefontalcortex
physical
coordination; sensoryprocessing;
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motivationemotionjudgment
Age 24
physicalcoordination; sensory
processing;
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Back of brain matures before tothe front of the brain sensory and physical activities
favored over complex, cognitive-
demanding activities propensity toward risky, impulsive
behaviors group setting may promote risk taking
poor planning and judgment
Arrested Development
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Back of brain matures before tothe front of the brain activities with high excitement and
low effort are preferred
poor modulation of emotions (hotemotions more common than coldemotions)
heightened interest in novel stimuli
Arrested Development
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Neurodevelopment likely
contributes to.
> risk taking (particularly in groups)
> propensity toward low effort - highexcitement activities
> interest in novel stimuli
< capacity for good judgment &
weighing consequences
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susceptible to alcohol thanadults? Adult studies suggest that the areas of the adolescent brain
that are remodeled are sensitive to the effects of alcohol
Four pieces of evidence
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susceptible to alcohol thanadults?
1. Adolescent rats are less sensitive to
the sedative and motor impairmenteffects of intoxication
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Supporting Human Studies1. Reduced sensitivity to intoxication
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Current (Past Year) Adults1 17-202 18-193
Alcohol Dependence 7.2 14.610.5
1NRC Report, 19992NY State Household, 19933MN Student Survey, 1995
Comparison of AlcoholDependence Rates
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urvey a a ugges aAdolescents Are Less Sensitive toAlcohols Effects
148
26 2430 32
0
20
40
60
80
100
8th Graders 10th Graders 12th Graders
5+ drinks in row, past 2 weeks
Been drunk past month
Monitoring the Future, 2001
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susceptible to alcohol thanadults?2. Adolescent rats are more sensitive
to the social disinhibition inducedby alcohol use
Wanna lookfor some cheese
with me?
Sure!
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susceptible to alcohol thanadults?3. Adolescent drunk rats perform
worse on memory tasks thanadult drunk rats
Ugh??
disrupts the hippocampus
brain damage in the PFC
converts
information to
memory
planned
thinking
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Supporting Human Studies3. Greater adverse effects to cognitive
functioning
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Alcohols Effects Adolescents with a history of extensive alcohol use,
compared to a control group.
Reduced hippocampus volume (10-35%)
Less brain activity during memory tasks
(Brown, 2002; Wuethrich, 200
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susceptible to alcohol thanadults?4 Hyperexcitability issue
Alcohol relieves hyperexcitability state
Relief is temporary; continued seeking of
alcohol is reinforced
Hyperexcitability is a key characteristic ofconduct disorder, ODD and ADHD, which areoften co-morbid with alcohol use disorders
Hyperexcitability. may have its origins in neurological deficits found in non-alcoholic relatives - suggests
inheritance of this trait
ADHD
OD
Con Di
Sub Use Dis
Are adolescents more
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susceptible to alcohol thanadults?
1. Reduced sensitivity to
intoxication2. Increased sensitivity to socialdisinhibitions
4. Medicates hyperexcitability
Increases reinforcing properties
Are adolescents more
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susceptible to alcohol thanadults?Greater deficits
3 Greater adverse effects tocognitive functioning
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Neurodevelopment likely
contributes to.
> risk taking (particularly in groups)
> propensity toward low effort - highexcitement activities
> interest in novel stimuli
< capacity for good judgment &
weighing consequences
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Implications of this new science:
Enhancing parenting, prevention and treatment
1. Will parents, health service providers andyoung people benefit by this knowledgeabout basic principles of braindevelopment?
The developing brains software does notinclude program language that says onsecond thought
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Implications of this new science:
Enhancing parenting, prevention and treatment
1. Will young people benefit by learning about basicprinciples of brain development?
2. Will young people be influenced by thescience that suggests drug use has a
deleterious effect on the developing brain?
Going beyond this is your brain on drugs
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THANK [email protected]