u tah a ddiction c enter university of utah adolescent brain development “time of turmoil and...

Utah Addiction Center

University of Utah

ADOLESCENT BRAIN ADOLESCENT BRAIN DEVELOPMENTDEVELOPMENT

““TIME OF TURMOIL AND TIME OF TURMOIL AND TRIUMPH”TRIUMPH”

BARBARA SULLIVAN, Ph.D.September 14 and 15, 2009


University of Utah

GOALS

To increase participant understanding of: the structures, functions, and stages of

development of the brain how adolescence has changed over the last 150

years the differences between adult and adolescent

thinking the impact of abuse and neglect on the brain current trends in adolescent alcohol use the impact of alcohol use on the brain what clinicians, prevention specialists, and

communities can do to support healthy adolescent development


University of Utah

CAVEATS• New discoveries — research is still in its infancy• Do NOT over-interpret or interpret too

simplistically• Research is not to the point that it can inform

causal models• Most research has been conducted on male

animals — we assume the information transfers to people

• Behavior is the result of complex interactions among individual, environment, genetics, situation, cultural expectations, and numerous other factors


University of Utah

BRAIN STRUCTURES AND FUNCTIONS


University of Utah

BRAIN FACTS• Brain weighs

approximately 3 pounds• Brain has approximately

100 billion neurons and 1 trillion supporting cells

• Neurons grow and organize themselves into efficient systems that operate a lifetime

• Brain controls ALL activities

• Emotion and cognition are intertwined

• Neurons can re-route circuits

• Brain and environment involved in delicate duet

• Brain never stops adapting and changing


University of Utah


University of UtahIllustration by Lydia Kibuik, 2003


University of Utah

Every mammal’s brain has the same basic structure- cortex, cerebellum, and brain stem–

cortical surface area is key

EVOLUTION OF THE NEW BRAIN


University of Utah

CHALLENGE OF UNDERSTANDING THE BRAIN

• What is the link between the anatomy of a brain and the workings of the mind—our thoughts, emotions, memories, and behaviors?

• There are no moving parts—it does not operate mechanically as our hearts, legs, hands, and lungs do. So what is going on in there?


University of Utah

BRAIN STRUCTURES

• Frontal Lobe• Parietal Lobe• Temporal Lobe• Occipital Lobe

• Cerebellum• Corpus Callosum• Brain Stem


University of Utah

INTEGRATION OF THE LOBES

• The different lobes of the brain work together– like instruments in an orchestra to play music or letters in the alphabet to form words

• Each area makes specialized contributions to certain functions, but many brain regions participate in forming human thoughts and behaviors


University of Utah

FRONTAL LOBE• Seat of personality, judgment, reasoning,

problem solving, and rational decision making• Provides for logic, understanding of

consequences, and emotional/behavioral regulation

• Governs impulsivity, aggression, ability to organize thoughts, and plan for the future

• Controls capacity for abstraction, attention, cognitive flexibility, and goal persistence

• Undergoes significant changes during adolescence — not fully developed until mid 20’s (Geidd, 2002)


University of Utah

FRONTAL LOBE• As the “prefrontal cortex” area of the

frontal lobe matures, through experience and practice, teens can reason better, develop more impulse control, and make better judgments

• Prefrontal cortex is one of the last areas of the brain to fully develop (Sowell, 2001)

• Increased need for structure, mentoring, guidance


University of Utah

COMPONENTS OF EXECUTIVE FUNCTIONS AND SAMPLE BEHAVIORS

COMPONENTS BEHAVIORS

Goal Directedness Establishing and maintaining goals; evaluating progress, using strategies

Initiation/Inhibition Initiating behavior independently, self-cueing, inhibiting inappropriate behaviors

Flexibility/Perseverance Generating novel possibilities, flexibility, performing contingency based revisions, strategizing


University of Utah

COMPONENTS BEHAVIORS

Abstract Reasoning Using rule-guided thinking, forming concepts, using hierarchical and temporal relationships

Reward Appraisal Evaluating reward likelihood, using reward appraisal to guide behavior

Social Appraisal Understanding social norms and cues, incorporating social information into decision making

Brown et al., 2008


University of Utah

TEMPORAL LOBES• Responsible for hearing, understanding speech,

and forming an integrated sense of self• Responsible for sorting new information and for

short term memory• Contains the limbic-reward system

(amygdala, hippocampus, nucleus acumbens, and vta)

• Developmental delays, deficits, or over-stimulation of the limbic area may increase vulnerability to high risk behaviors (Clark, Thatcher, & Tapert, 2008)

• Matures around ages 18-22


University of Utah

TEMPORAL LOBE/LIMBIC SYSTEM

• Limbic system regulates emotions and motivations— particularly those related to survival—such as fear, anger, and pleasure (sex and eating)

• Feelings of pleasure/reward are very powerful and self-sustaining. Pleasurable behaviors activate a circuit of specialized nerve cells in the limbic area that is devoted to producing and regulating pleasure called the reward system


University of Utah

REWARD SYSTEM

• Drugs of abuse activate the reward system in the limbic area of the brain—producing powerful feelings of pleasure

• Desire to repeat drug using behavior is strong• Drugs of abuse can/do exert powerful control

over behavior because they act directly on the more primitive, survival limbic structures— over-ride the frontal cortex in controlling our behavior


University of Utah

PARIETAL LOBESPARIETAL LOBES

• Integrate auditory, visual, and tactile signals

• Right lobe– coordinates visual/spatial relationships

• Left lobe– coordinates spoken or written language

• Matures around ages 16-17


University of Utah

OCCIPITAL LOBESOCCIPITAL LOBES

• Primarily responsible for coordinating sight• Primary visual area where “pictures” are

received from the eyes and relayed to other parts of the brain for interpretation

• Visualization requires more than “seeing”–“seeing”– the primary visual cortex processes information, temporal lobe recognize what we see, and the parietal lobes process information as we move through the space we see.


University of Utah

• INFO FROM DANA BOOK

Robert Finkbeiner, Dana Brain Book


University of Utah

CEREBELLUMCEREBELLUM

• Located at the base of the brain • Responsible for motor coordination• Recent research suggests that it is involved in

“coordinating” thinking processes– “mental clumsiness” (Geidd, 2002)

• Physical exercise is important for the development of the cerebellum – undergoes significant change during adolescence


University of Utah

CORPUS CALLOSUMCORPUS CALLOSUM

• Thick bundle of nerves that connects the two sides of the brain and relays information between the two cerebral hemispheres

• Involved in creativity and problem solving

• Influences language, learning, and associative thinking

• Changes significantly during adolescence (Geidd, 1999)


University of Utah

BRAIN STEMBRAIN STEM

• All nerve fibers pass through this area

• Performs sensory, motor, and reflex functions

• Contains vital nerve centers that control breathing, heart rate, body temperature, and gastrointestinal activity

• Connects the brain with the body


University of Utah

BRAIN CIRCUITRYBRAIN CIRCUITRY


University of Utah

Brain CircuitryBrain Circuitry• NEURON —specialized cell designed to

transmit information to other nerve cells and muscles

• Each neuron consists of a cell body, axon, and dendrite

• Axon– an electricity conducting fiber that carries information away from the cell body

• Dendrite– receives messages from other neurons

• Synapse– contact point where one neuron chemically “communicates” with another neuron

Brain Facts, The Society for Neuroscience, 2002


University of Utah (Illustration by Lydia Kibiuk, 1996)


University of Utah


• Neurons “communicate” by transmitting electrical impulses along their axons

• Axons send chemical neurotransmitter messages across a synapse to the receiving dendrite of the target neuron

• Each neuron has an average of 6,000 dendrite receptors

• Dendrite receptor sites are specialized areas— “lock and key” or “molecular handshake”


University of Utah


• A neuron may receive many different messages at the same time (Prioritize)

• Each neuron has to “interpret” incoming messages

• Neuronal communication is currently under intense study because it plays such a critical role in health and well being


University of Utah


• Electrical impulses travel along axon at speeds up to 250 mph (mylenation)

• Neurons forging connections with other neurons underpin learning

• Our brains are adaptable and can reflect on and learn from experience

• Neural connections are shaped by genetics and experience


University of Utah

BRAIN CIRCUITRYBRAIN CIRCUITRY• Gray matter contains neurons that are

responsible for “thinking” (100 billion)• White matter contains suportive cells with

nutritive roles (dendrites—1 trillion)• Myelin is a layer of insulation that progressively

insulates these supportive cells and is whitish in color

• Myelin makes white matter more efficient—just like insulation on electric wires—contributes to overall cognitive functioning (100x faster)

• Myelin affects the speed and quality of brain activity (Paus, et al., 1999)


University of Utah

NEUROTRANSMITTERSNEUROTRANSMITTERS• All messages are passed to connected

neurons through a form of chemicals called neurotransmitters

• Neurotransmitters are released from the end of the axon, cross the synapse, and bind to the specific receptors on the dendrites of the targeted neuron

• Neurotransmitters bind with specific receptor sites on the receiving dendrite


University of Utah

MAJOR NEUROTRANSMITTERSMAJOR NEUROTRANSMITTERS

• Acetylcholine —regulates memory• Dopamine —produces pleasure through the

“reward system”; multiple functions including controlling movement, regulates hormonal responses, important to cognition and emotion; abnormalities in dopamine levels have been implicated in schizophrenia

• Serotonin —plays a role in sleep; involved in sensory perception; and involved in controlling emotional states such as anxiety and depression


University of Utah

MAJOR NEUROTRANSMITTERS

• Glutamate — excites the firing of neurons, aids process of memory

Gamma-aminobutyric (GABA) — inhibits the firing of neurons


University of Utah

DEVELOPMENTAL VULNERABILITY

• During adolescence, the prefrontal cortex (PFC), limbic system areas, and the white matter myelin are undergoing many changes (Chambers, 2003; Spear, 2000)

• These areas serving cognitive, behavioral, and emotional regulation may be particularly vulnerable to adverse alcohol effects

• Deficits or developmental delays in these structures and their functions may underlie vulnerabilities to alcohol use/abuse (Clark, Thatcher, & Tappert, 2008)


University of Utah

OVERPRODUCTION AND OVERPRODUCTION AND PRUNINGPRUNING

CRITICAL PEAKS OF BRAIN DEVELOPMENT


University of Utah

OVERPRODUCTION AND OVERPRODUCTION AND PRUNINGPRUNING

• Brain development occurs in 2 basic stages– growth spurts/overproduction of neurons and pruning

• Critical phases: in utero 0-3 years overproduction

10-13 years Overproduction results in significant increase in

the number of neurons and synapsesExuberant growth during these 3 phases gives

the brain enormous potential

Begley, 2000; Geidd, 1999


University of Utah

PRUNINGPRUNING• These 3 critical phases are quickly followed by a

process in which the brain prunes and organizes its neural pathways

• LEARNING is a process of creating and strengthening frequently used synapses (brain discards unused synapses)

• Brain keeps only the most efficient and “strong” synapses

• Children/teens need to understand that they decide which synapses flourish and which are pruned away (Geidd, 1999)


University of Utah

PRUNING

• “USE IT OR LOSE IT”– Reading, sports, music, video games, x-box, hanging out—whatever a child/teen is doing—these are the neural synapses that will be retained

• How children/teens spend their time is CRUCIAL to brain development since their activities guide the structure of the brain (Geidd, 1999)


University of Utah

What sorts of media are young What sorts of media are young people consuming?people consuming?

Every year young people will see about 1,000 commercials advertising beer.

2/3 of young people have a TV in their room, 61% have no parental guidelines.

Annually alcohol manufactures spend over $1 BILLION in TV, radio, print, and internet advertising.

Young people spend an average of 10 hours per week on the internet.

58% of young people have accessed websites of a violent or sexual nature.

82% of websites target youth.

Young people sped an average of 1-2 hours daily listening to music.

63% of rap songs make reference to drug use, as do 10% of songs in other genres.


University of Utah

BRAIN DEVELOPMENTBRAIN DEVELOPMENT

• Continued synaptic pruning, neural connection/integration, capacity to process information, and mylenation (driven by experience and practice)– these structural changes are believed to underlie the functional integration of frontal regions with the rest of the brain – adolescent into adultadolescent into adult (Luna & Sweeny, 2004)


University of Utah

BRAIN DEVELOPMENT• White matter development may underlie

advancing executive functioning (Luna and Sweeney, 2004; Luna et al., 2001)

• Delays or deficits in the development of PFC may result in “neurodevelopmental dysmaturation” which can lead to “psychological dysregulation”

• Psychological dysregulation is a deficiency in the ability to regulate attention, emotions, and behavior in response to environmental challenges (Clark and Winters, 2002)


University of Utah

PSYCHOLOGICAL DYSREGULATION

• Alcohol Use Disorders (AUD) typically do not happen in isolation– instead they appear to be correlated with persistent behavioral characteristics including:

* attentional deficits; ADD, ADHD* conduct disorders; anti-social* irritability; aggression, diminished

constraint* major depressive disorder;

depression, anxiety

Clark et al., 2005; Tappert et al., 2002; Chassin et al., 1999; Tarter et al., 1999


University of Utah

DEFINING ADOLESCENCEDEFINING ADOLESCENCE


University of Utah

ADOLESCENCE HAS ALWAYSALWAYS BEEN CHALLENGING…

““Youth are heated by nature as drunken men by Youth are heated by nature as drunken men by wine” Aristotle (350 B.C.)wine” Aristotle (350 B.C.)

““I would that there were no age between 10-23, for I would that there were no age between 10-23, for there’s nothing in between but getting wenches with there’s nothing in between but getting wenches with child, wronging the ancientry, stealing, fighting…” child, wronging the ancientry, stealing, fighting…” Shakespeare “The Winter’s Tale”, Act III (..1594)Shakespeare “The Winter’s Tale”, Act III (..1594)


University of Utah

DISPARITIES OF ADOLESCENCEDISPARITIES OF ADOLESCENCE• Adolescence is a time of triumph, high energy,

great potential, resilient health, new found skills, creativity, humor…..

• Adolescence is also a time of turmoil often associated with high risk behaviors, impulsivity, and poor decision making

• Dramatic increase in death, disability, suicide, homicide, serious accidents, aggression, violence, emotional disorders, substance use, and risky sexual behaviors


University of Utah

REWARD SENSITIVITYREWARD SENSITIVITY

• Changes in reward sensitivity that occur at puberty lead adolescents to seek more novelty and require a higher level of stimulation to achieve the same subjective feeling of pleasure

• Changes in the limbic system, neuro- limbic system, neuro- endocrinology, and an immature self endocrinology, and an immature self regulatory systemregulatory system are implicated (Steinberg, 2004)


University of Utah

ADOLESCENCEADOLESCENCE

• AwkwardAwkward period between sexual maturation and the attainment of adult roles and responsibilities

• Begins with the domain of physical/biological changes related to puberty, but it ends in the domain of social roles

• Encompasses the transition from the status of a child (one who requires monitoring) to that of an adult (responsible for behavior) [Dahl, 2003]


University of Utah

STUDY OF ADOLESCENTS

• G. S. Hall, psychologist, began the modern study of adolescence about 100 years ago

• Increase in adolescent-related research in the early 1990’s; second increase began focusing on adolescent brain development in 1998

• Most research is conducted on babies and toddlers


University of Utah

ADOLESCENCEADOLESCENCE

• Adolescence is much broader and longer than the teenage years alone (has changed significantly over the past 150 years)

• Adolescence now stretches across more than a decade, with pubertal onset often beginning by age 9-12 and adult roles delayed until mid twenties (Worthman, 1995)


University of Utah

ADOLESCENCE

• In the early 1900’s, the interval between puberty and achieving adult status was typically 2 years for girls and 4 years for boys (Schlegel and Barry, 1991)

• While puberty is occurring earlier in many industrial societies, marriage and other adult roles are often delayed; in the U.S. the average age of menarche is 12 and average age of 1st marriage is 26 (Dahl, 2004)


University of Utah

ADOLESCENCE

• Most elements of cognitive development show a trajectory that follows age and experience rather than the timing of puberty (Dahl, 2004)

• Research conducted by Martin, 2003, demonstrates a significant positive correlation between pubertal maturation and sensation seeking


University of Utah

ADOLESCENCEADOLESCENCEPUBERTYPUBERTY

Romantic motivationRomantic motivation

Sexual interestSexual interest

Emotional intensityEmotional intensity

Sleep cycle changesSleep cycle changes

AppetiteAppetite

Risk for affective disorders Risk for affective disorders (girls)(girls)

Increase in risk taking, Increase in risk taking, sensation seeking, and sensation seeking, and novelty seekingnovelty seeking

AGE/EXPERIENCEAGE/EXPERIENCE

PlanningPlanning

Logic, reasoningLogic, reasoning

Inhibitory controlInhibitory control

Problem solvingProblem solving

Understanding Understanding consequencesconsequences

Affect regulationAffect regulation

Goal setting and pursuitGoal setting and pursuit

Judgment and abstract Judgment and abstract thinkingthinking

Dahl, 2004


University of Utah

ADOLESCENCE VS. ADULTSADOLESCENCE VS. ADULTS

• Being a responsible adult requires developing self-control over behavior and emotions– must be able to appropriately inhibit behaviors despite STRONG FEELINGSSTRONG FEELINGS

• The ability to integrate these multiple components of behavior, cognition, and affect in the service of long term goalsservice of long term goals involves neurobehavioral systems that are among the last regions of the brain to fully mature (Dahl, 2004)


University of Utah

NAVIGATING ADOLESCENCENAVIGATING ADOLESCENCE• The most widely implicated factor

associated with maladaption vs. resiliencemaladaption vs. resilience in adolescence is REGULATORY CAPACITY (RC) [Kupfer & Woodward, 2004]

• Behavioral control (RC)Behavioral control (RC) requires tremendous effort; adolescents need practice being consistent and integrating RC

• PFC and white matter development are needed for regulatory capacity


University of Utah

NAVIGATING ADOLESCENCENAVIGATING ADOLESCENCE

• What makes this possible?– Driven by experience and practice– Psychological regulation of attention,

emotions, and behavior– Continued synaptic pruning and mylenation– Mentoring appropriate response patterns in

the face of everyday life and decision making


University of Utah

Critical Differences BetweenCritical Differences Between Adult and Adolescent ThinkingAdult and Adolescent Thinking


University of Utah

Why is it that a young person is Why is it that a young person is not able to drive a car until not able to drive a car until 1616, ,

vote until vote until 1818, drink alcohol until , drink alcohol until 2121, rent a car from a commercial , rent a car from a commercial

agency until agency until 2525, but in some , but in some states, can stand trial for murder states, can stand trial for murder

at age at age 1212 or or 1313? ? (Dahl, 2004)(Dahl, 2004)


University of Utah

DISPARITIES OF DISPARITIES OF ADOLESCENCEADOLESCENCE

• Adolescence is a TRANSITIONALTRANSITIONAL period during which a child is becoming, but is not yet, an adult

• Adolescent brains are far less developedfar less developed than we previously believed

• Normal adolescent development includes conflict, risk taking, facing insecurities, creating an identity, mood swings, self-absorption, etc.


University of Utah

ADOLESCENT BRAIN DEVELOPMENT

• UnderdevelopmentUnderdevelopment of the frontal lobe/prefrontal cortex and the limbic

system make adolescents more prone to “behave emotionally or with ‘gut’

reactions” (Yurgelun-Todd, 1999)

• Adolescents tend to use an alternative part of the brain– the AMYGDALAAMYGDALA (emotions (emotions & aggression)& aggression) rather than the prefrontal prefrontal cortexcortex (reasoning)(reasoning) to process information


University of UtahIllustration by Lydia Kibiuk, 2003


University of Utah


• Amygdala and nucleus acumbens (limbic system within the temporal lobes) tend to dominate the prefrontal cortex functions– this results in a decrease in reasoned thinking and an increase in impulsiveness

• Because of immature brains, adolescents do not handle social pressure, instinctual urges, and other stresses the way adults do

• A major part of adolescence is learning how to assess risk and consequences — adolescents are not yet skilled at these tasks (Dahl, 2004)


University of Utah

HOT AND COLDHOT AND COLD COGNITIONCOGNITION

• Thoughts and emotions are intertwinedThoughts and emotions are intertwined – teens need to develop a balance between cognitive and affective systems of the brain

• ““COLD”COLD” cognition refers to thinking under conditions of low emotions and/or arousal

• ““HOT”HOT” cognition refers to thinking under conditions of strong feelings or arousal

• Decisions made under conditions of strong affect are difficult to influence by cool rational difficult to influence by cool rational thoughtthought alone


University of Utah

HOT AND COLD COGNITIONHOT AND COLD COGNITION• Decision making in teens cannot be fully

understood without considering the role of emotions and the interaction between thinking and feeling (Dahl, 2003)

• Teen decisions are unlikely to emerge from a logical evaluation of the risk/benefits of a situation – rather decisions are the result of a complex set of competing feelings – desire to look cool, fear of being rejected, anxiety about being caught, excitement of risk, etc.


University of Utah

HOT AND COLD COGNITIONHOT AND COLD COGNITION

• Adolescent brain is a “vulnerable”“vulnerable” system that could failcould fail under “hot” high demanding situations – where the circuitry is not sufficiently established to sustain sustain adult level cognitive control of behavior in the face of heightened states of heightened states of emotion, motivation, distracting stimuli, emotion, motivation, distracting stimuli, oror competing taskscompeting tasks (Luna & Sweeny, 2003)


University of Utah

ADOLESCENT BRAINADOLESCENT BRAIN

• DLPFCDLPFC is linked to the ability to inhibit impulses, weigh consequences, prioritize, and strategize – this area is still “under construction” until late 20’s (Giedd, 1999)

• Wernicke’sWernicke’s area (reception of speech) and Broca’sBroca’s area (production of speech) undergo substantial changes during the teen years – impacts ability to listen and impacts ability to listen and express oneself express oneself


University of Utah


• Adolescents are not very skilled at distinguishing the subtlety of facial expression (excitement, anger, fear, sadness, etc.)—results in a lot of miscues—leads to lack of communication and inappropriate behavior

• Differences in processing, organization, and responding to information/events leads to misperceptions and misunderstanding verbal and non-verbal cues


University of Utah

Adolescent Brain

Adult Brain

YURGELUN-TODD, 1999


University of Utah


• To appreciate consequencesappreciate consequences of risky behavior, one has to have the ability to think through potential outcomes and understand the permanence of consequences, due to an immature prefrontal cortex, teens are not skilled at doing this

• Teens do not take information, organize it, and understand it in the same way that adults do—they have to learn how to do thislearn how to do this


University of Utah

ADOLESCENT BRAIN DEVELOPMENT

• Important to understand that teens often fail to heed common sense or adult warnings because they simply may not be able to understand and/or accept reasons that seem logical and reasonable to adults (difference in evaluating positive & negative consequences {Fromme et al., 1997})

• Adolescents may know “right from wrong”, but they may not be able to prioritize when stressed with social/peer pressure

• NEVER assume that you and a teen are having the same understanding of a conversation

u tah a ddiction c enter university of utah adolescent brain development “time of turmoil and...

Documents