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Adolescence, the Developing Brain and Drug Abuse

Adolescence, the Developing Brain and Drug Abuse. Ken Winters, Ph.D. Department of Psychiatry University of Minnesota winte001@umn.edu 5 th Annual Georgia School of Addiction Studies Savannah, GA August 30, 2011. Background. Brain development. Summary. Brain development,

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Adolescence, the Developing Brain and Drug Abuse

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  1. Adolescence, the Developing Brain and Drug Abuse Ken Winters, Ph.D. Department of Psychiatry University of Minnesota winte001@umn.edu 5th Annual Georgia School of Addiction Studies Savannah, GA August 30, 2011

  2. Background • Brain development • Summary • Brain development, • risk taking and health • Implications • for professionals

  3. Background • Brain development • Summary • Brain development, • risk taking and health • Implications • for professionals

  4. Emerging Science:Brain Imaging • New insights • 1990’s information explosion due to the development of brain imaging techniques (e.g., CT, PET and MRI).

  5. Background • Brain development • Summary • Brain development, • risk taking and health • Implications • for professionals

  6. Adolescence is a period of profound brain maturation. • We thought brain development was complete by adolescence • We now know… maturation is not complete until about age 25!!!

  7. Important ages of majority and privileges 16 - emancipation - driving 18 - gambling (usually age 21 when alcohol served) - smoking (some at age 19 - military 21 -drinking

  8. An Immature Brain = Less Brakes on the “Go” System

  9. Males Females Brain Weight by Age I’m adult-size now! Newborn Age Slide courtesy Sion Kim Harris, Ph.D. Source: Dekaban, A.S. and Sadowsky, D. Annals of Neurology, 4:345-356, 1978

  10. Volume Adolescence Metabolism Myelination Blood Flow Receptors Synaptic Refinement Brain Development RATE OF CHANGE 7 1 2 16 30 Post-birth Age Prenatal Tapert & Schweinsburg (2005)

  11. Maturation Occurs from Back to Front of the Brain Images of Brain Development in Healthy Youth (Ages 5 – 20) Earlier: Motor Coordination Emotion Motivation Later: Judgment Blue represents maturing of brain areas Source: PHAS USA 2004 May 25; 101(21): 8174-8179. Epub 2004 May 17.

  12. Construction Ahead • When the pruning is complete, the brain is faster and more efficient. • But… during the pruning process, the brain is not functioning at full capacity.

  13. An Immature Brain = Low Brain Power Source: US News & World Report, 2005

  14. Taking the Same Ability Test at Age 11 & Age 80: Scottish Mental Survey 1932 Deary et al. (2004) Journal of Personality and Social Psychology, 86, 130-147.

  15. Brain Development May Reveal These Tendencies (Dahl, 2004) • Preference for …. • physical activity • high excitement and rewarding activities • activities with peers that trigger high intensity/arousal • novelty • Less than optimal.. • control of emotional arousal • consideration of negative conseq. • Greater tendency to… • be attentive to social information • take risks and show impulsiveness

  16. Background • Brain development • Summary • Brain development, • risk taking and health • Implications • for interventions

  17. Standard View • Adolescents underestimate risk • Adolescents believe they are invulnerable • Adolescents engage deficient cognitive processes when making decisions • Adolescents are unaware of the dangers associated with risky behavior

  18. Risk-Taking • Based on science of brain development, a modern view of risk taking in adolescence… • is normative; important to development • has evolutionary significance • is influenced by emotional and contextual, not cognitive, factors

  19. Several Findings in the Literature(see Steinberg for a review, JMATE conference, 2010) Delayed Discounting Self-Reported Impulse Control (Barratt) Reward Sensitivity (Iowa Gambling Task) Waiting Before Acting (Tower of London) Self-Reported Sensation Seeking (Zuckerman) fMRI study of risk taking (Steinberg lab will be publishing this soon)

  20. Delay Discounting(Delay Reward) Would you rather have $200 today or $1,000 in six months? Lower figure raised or lowered to middle point depending on answer, and question repeated until no preference between immediate and delayed reward $600 today versus $1,000 in six months $400 today versus $1,000 in six months Repeated with 9 trials (with varying immediate amounts) in each of 6 different time intervals 1 day, 1 week, 1 month, 3 months, 6 months, 1 year Lower amount accepted short-term indicates stronger need for short-term gratification

  21. Young Adolescents Show Stronger Preference for Immediate Reward Steinberg et al., 2009

  22. Adolescence and alcohol

  23. Sidebar: Drug Addiction and the Brain

  24. Dopamine Neurotransmission 1100 AMPHETAMINE 1000 900 800 700 600 500 % of Basal Release 400 300 200 frontal cortex 100 0 0 1 2 3 4 5 hr Time After Amphetamine FOOD 200 nucleus accumbens VTA/SN 150 % of Basal Release 100 Empty 50 Box Feeding 0 0 60 120 180 Time (min) Di Chiara et al.

  25. Your Brain on Cocaine PET scan 1-2 Min 3-4 5-6 6-7 7-8 8-9 9-10 10-20 20-30 Yellow = cocaine is binding or attaching itself to areas of the brain

  26. Dopamine D2 Receptors are Lower in Addiction Cocaine DA DA DA DA DA DA DA DA DA DA DA DA Meth Reward Circuits Non-Drug Abuser DA D2 Receptor Availability Alcohol DA DA DA DA DA DA Heroin Reward Circuits Drug Abuser control addicted

  27. What about recovery?

  28. Your Brain After Cocaine Normal Cocaine Addict - 10 days after use Cocaine Addict - 100 days after use Yellow = normal brain functioning

  29. Adolescence and alcohol • Are adolescents highly susceptible to alcohol and other drugs? • Several lines of evidence address this question. • epidemiological surveys • animal data

  30. Prevalence of Past-Year DSM-IV Alcohol Dependence: United States, 2001-2002(Grant, B.F., et al., Drug and Alcohol Dependence, 74, 223-234, 2004) %

  31. Percentages of Past Year Alcohol Use Disorder (Abuse or Dependence) Among Adults Aged 21 or Older, by Age of First Use (SAMHSA, 2005) Fewer Problems in Those Who Start Later % Age Started Drinking

  32. Percentages of past year alcohol use disorder among those with a recent onset (prior 2 years; n = 4074) of alcohol use (Winters & Lee, 2007) Lower Rates with Older Recent Users % * * * * Age of Person in Years * p <= .05; compared to 22-26y group

  33. Percentages of past year cannabis use disorder among those with a recent onset (prior 2 Years; n = 2176) of cannabis use (Winters & Lee, 2007) Lower Rates with Older Recent Users % * * * * * * * Age of Person in Years * p <= .05; compared to 22-26y group

  34. Are adolescents highly susceptible to alcohol and other drugs? Comparing adolescent and adult rats, both having no prior exposure to alcohol and matched on temperament…. Adolescent rats are less sensitive to the sedative and motor impairment effects of intoxication

  35. The Water Maze Test Hidden • Saline vs alcohol • Measures • Swimming speed • Time to find platform • adolescent rats vs adult rats • Saline groups: no age difference • Alcohol groups: both worse than saline groups; adol better than adults Slide courtesy Sion Kim Harris, Ph.D.

  36. Are adolescents highly susceptible to alcohol and other drugs? Comparing adolescent and adult rats, both having no prior exposure to alcohol and matched on temperament…. Adolescent rats are more sensitive to the social disinhibition effects of alcohol.

  37. Wanna look for some cheese with me? Sure!

  38. Are adolescents more susceptible to alcohol than adults? 1. Epidemiological data 2. Adolescent rats are less sensitive to the sedative and motor impairment effects of intoxication. 3. Adolescent rats are more sensitive to the social disinhibition effects of alcohol. #2 and #3 : May contribute to binge drinking and increased risk to alcohol dependence.

  39. Adolescence, driving and alcohol.

  40. Driving in the Kid Lane • Although teenagers represent only 6 percent of drivers, they are involved in 14 percent of fatal crashes • Sources • Inexperience: Highest crash rate: the first month after teenagers got their license. • The crash rate drops dramatically with the next five months; in 12 months it drops by a factor of 3-fold • Distractions: cell phones, other passengers, adjusting radio • Drug use

  41. Motor Vehicle Crash and Age of Drinking Onset (N = 4,021; national sample) Hingson et al., 2009

  42. Background • Brain development • Summary • Brain development, • risk taking and health • Implications • for professionals

  43. Implications • Social/Environmental • Self-regulation skills • Parenting

  44. Implications for Interventions • Social/Environmental • Self-regulation skills • Parenting

  45. Minimum Legal Drinking Age (MLDA) and Vehicle Fatalities Among Young Drivers (16 – 20) raised MLDA Percent of fatally injured passenger vehicle drivers age 16 – 20 with positive BACs, by age 1982 – 2008 (Longthorne et al., 2010) %

  46. Allstate ad, NY Times, May, 2007

  47. Impact of Peer Presence onRisky Driving in Simulated Context peer effect Chein et al., in press

  48. Implications • Social/Environmental • Self-regulation skills • Parenting

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