Winters Brain 2004

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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

[email protected]

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 neurodevelopment 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]

Documents

Winters Brain 2004