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Marijuana

NIDA. Marijuana. NATIONAL INSTITUTE ON DRUG ABUSE. Prepared by Dr. Linda Thomas. What Have We Learned Through Research?. 83 million Americans have tried it at least once. An estimated 2.4 million Americans used it for the first time in 2001. Extent of the Problem….

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Marijuana

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  1. NIDA Marijuana NATIONAL INSTITUTE ON DRUG ABUSE Prepared by Dr. Linda Thomas What Have We Learned Through Research?

  2. 83 million Americans have tried it at least once An estimated 2.4 million Americans used it for the first time in 2001 Extent of the Problem… Marijuana is the Most Commonly Used Illicit Drug In the U.S. Source: 2001 National Household Survey on Drug Abuse, SAMHSA

  3. Types of Drugs Used By Past Month Illicit Drug Users Aged 12 and Older: 2001 Marijuana Only Drug Other than Marijuana 24% 56% 20% Marijuana and Some Other Drug Source: 2001 National Household Survey on Drug Abuse, SAMHSA

  4. Percent of Students Reporting Any Illicit Drug Use in Past Year, by Grade Source: Monitoring the Future Study 2002

  5. Percent of Students Reporting Use of Marijuana in Past Year, by Grade Source: Monitoring the Future Study 2002

  6. Research on Marijuana Has Taught Us A Lot About: Marijuana, specifically Drug abuse/addiction, in general

  7. Neuroscience of Marijuana Use and Abuse

  8. - Tetrahydrocannabinol 9` (THC)

  9. Cannabinoid Receptor

  10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Cannabinoid Receptors

  11. CB1 Cannabinoid Receptors in Rodent Brain Gifford, A.N. et al., Chemistry and Physics of Lipids, 21(1-2), pp. 65-72, December 2002.

  12. Nucleus accumbens Dopamine pathways (reward, eurphoria)

  13. Effects of Drugs on Dopamine Levels COCAINE AMPHETAMINE Accumbens 1100 Accumbens 400 1000 900 DA 800 DA 300 DOPAC 700 DOPAC % of Basal Release HVA HVA 600 % of Basal Release 500 200 400 300 100 200 100 0 0 0 1 2 3 4 5 hr Time After Amphetamine Time After Cocaine MORPHINE NICOTINE 250 Accumbens 250 Dose (mg/kg) 200 Accumbens 0.5 200 Caudate 1.0 2.5 % of Basal Release 150 % of Basal Release 10 150 100 0 1 2 3 hr 100 0 1 2 3 4 5 hr 0 0 0 1 2 3 4 5hr Time After Nicotine Time After Morphine Source: Di Chiara and Imperato

  14. Acquisition of THC Self-Administration Behavior In Squirrel Monkeys Effects of Injection Dose on Self-Administration Behavior Tanda, G. et al., Nature Neuroscience, 3(11), November 2000. Recently, Self-Administration of THC Has Been Demonstrated in A Variety of Animal Models

  15. AND… A Cannabinoid Antagonist Can Block THC Self-Administration Tanda, G. et al., Nature Neuroscience, 3(11), November 2000.

  16. Why Do Some People Use and Others Don’t?

  17. Genetics Gene/EnvironmentInteraction Environment

  18. Heritabilities Derived From Twin Studies DRUG Males Females Heroin (opiates) Sedatives Marijuana Cocaine Hallucinogens Nicotine 54%(Tsuang et al., 1996) 87%(Kendler, et al., 2000) 33%(Tsuang et al., 1996) 58%(Kendler, et al., 2000) 44%(Tsuang et al., 1996) 79%(Kendler et al., 2000) 79% (Kendler, et al., 2000) 53%(Carmelli et al., 1990) 79%(Kendler & Prescott, 1998) 81%(Kendler et al., 1999) 72%(Kendler et al., 1999)

  19. A Gene Has Recently Been Identified That May Play A Role in Drug Addiction… This Gene Controls An Enzyme Responsible for the Breakdown of Endocannabinoids, the Brain’s Own Cannabis-Like Compounds Source: Sipe, J.C. et al., PNAS, 99(12), pp 8394-8399, June 11, 2002.

  20. Consequences of Marijuana Abuse

  21. Acute Effects of Marijuana Initial Euphoria or "High" Followed by SedationSense of Time AlteredHearing Less DiscriminateVisual DistortionsDepersonalizationConcentration ImpairedDream-like States Prominent

  22. Other Acute Effects Heart Rate IncreasedBlood Pressure UnchangedOrthostatic Hypotension (At High Doses)Conjunctival ReddeningMuscle Strength DecreasedAppetite Increased (Variable)Food Intake Increased (Variable)

  23. What are the More Persistent Effects of Marijuana?

  24. PET Scans Examining Glucose Metabolism 4 Days After Last Use Volkow, N.D. et al., Psychiatry Research: Neuroimaging, 67, pp. 29-38, 1996.

  25. Deficits In Cognitive Function in Heavy Cannabis Users Have Been Shown to Persist For At Least 7 Days After Discontinuing the Drug Source: Pope, H.G. et al., Arch Gen Psychiatry, 58, October 2001.

  26. Verbal and visual memory Executive functioning Visuoperception Psychomotor speed Manual Dexterity In Very Heavy Marijuana Users, Persistent, Negative Dose-Related Effects Have Been Shown on Tests Measuring… Bolla, K.I. et al., Neurology, 59, pp. 1337-1343, 2002.

  27. Relationship Between Amount of Marijuana Smoked and Task Performance In 28-Day Abstinent Heavy Marijuana Users Note: high IQs are less likely to be affected on tests that require suppression of habit---frontal cortex function High Shipley IQ Group Low Shipley IQ Group Bolla, K.I. et al., Neurology, 59, pp. 1337-1343, 2002.

  28. Can Marijuana Cause Permanent Changes? Long-term, Yes; Permanent, Probably No

  29. Recent Research Suggests That In-Utero Cannabis Exposure Can Negatively Impact Certain Aspects of Executive Functioning Note: impact on attention/impulsivity and problem solving after 3 years of age--considerable equivocation Fried, P.A. and Smith, A.M., Neurotoxicology and Teratology, 23, pp. 1-11, 2001.

  30. Chronic Marijuana Use Has Been Shown to Be Associated With Poorer Academic Performanceand Higher Dropout Rates Lynsky, M. and Hall, W. Addiction, 95(11), pp. 1621-1630, 2000.

  31. Chronic Marijuana Use Has Been Shown to Be Linked To Poor Job Performanceand Increased Absences From Work Lehman, W.E.K. and Simpson, D.D. Journal of Applied Psychology, 77(3), pp. 309-321, 1992.

  32. Percentage Arrestees Detected As Marijuana Users Arrestee Drug Abuse Monitoring (ADAM) Program, NIJ AND… In the Last Decade, Marijuana Use Has Been On the Rise Among Arrestees Especially Youthful Ones

  33. Recent Research Has Validated the Reliability and Clinical Significance of Marijuana Withdrawal Effects Source: Budney, A. J. et al., Arch Gen Psychiatry, 58, October 2001.

  34. Budney, A.J., et al., Archives of General Psychiatry, 58(10), pp. 917-924, 2001.

  35. Marijuana Smokers Show Increased Aggressive Behavior During Withdrawal Days of Abstinence Kouri, E.M. et al., Psychopharmacology, 143, pp. 302-308, 1999.

  36. We Are Beginning to Better Understand What Makes Marijuana Addictive… And How These Mechanisms Are Affected by Other Drugs of Abuse

  37. For Example… Research Shows that the Central Mechanism Involved in Cocaine Relapse Is Closely Linked to the Sites Where Marijuana Has Its Effect Source: DeVries, T.J., et al., Nature Medicine, 7(10) October 2001.

  38. (antagonist) (agonist) (note: hole pokes for cocaine and for no reward) Source: DeVries, T.J., et al., Nature Medicine, 7(10) October 2001. And So…cannabinoid agonist reinstates cocaine-seeking Cannabinoid Receptor Antagonists May Prove To Be Useful Anti-Craving Agents

  39. In Addition to It’s Effects on the Brain… We Have Learned A Lot About Marijuana’s Potential to Affect Other Organ Systems

  40. Lung Toxicity Heavy Hashish Use: Chronic Bronchitis Chronic CoughHeavy Marijuana Use (5 Times a Day for 59 Days): Produces Airway Obstruction Marijuana Smoke Contains More "Tar" Than Tobacco Smoke Contains Carcinogenic Materials

  41. Endocrine Effects Male Sex Hormones: - Controversial Decrease in Testosterone - Usually Within Normal Range Decreased Sperm Production - No Evidence of InfertilityGynecomastia Has Been Implicated But Not Proven THC is Not EstrogenicFemale Sex Hormones: Suppressed LH Surge and Ovulation Increased Incidence of Anovulatory Cycles (Use More Than 4 Times a Week)

  42. Difficulties Associated With Establishing the Health Hazards of Marijuana Most Animal Studies Have Been Conducted Using High Doses of THC for Short Periods of TimeMarijuana is Used By Young Persons In the Best of HealthIntermittent Use of Small Doses May Underestimate HazardsUsed With Other Drugs -- Especially Tobacco and AlcoholMarijuana Use is An Emotional Topic

  43. Treatment for Marijuana Addiction

  44. Percentages of Persons Aged 12 to 25 Reporting Past Month Marijuana Use Source: SAMHSA, 1999 and 2000 NHSDAs

  45. Changes in Marijuana Treatment Admission Rates: 1993-1999 Source: 1999 SAMHSA Treatment Episode Data Set (TEDS).

  46. Number of Adolescent Marijuana Admissions, by Referral Source Source: 1999 SAMHSA Treatment Episode Data Set (TEDS).

  47. The Adolescent Treatment System Less than 1/10th of adolescents with substance dependence problems receive treatment Under 50% stay 6 weeks, 75% stay less than the 3 months recommended by NIDA From 1992 to 1998, admissions for treatment of primary, secondary or tertiary marijuana use disorders increased 115% (51,081 to 109,875) Source: Dennis, Dwaud-Noursi, Muck, & McDermeit, 2002; Hser et al., 2001; OAS, 2000

  48. Behavioral Therapies

  49. 40 35 30 25 Percentage of Participants 20 15 10 5 0 Marijuana Abstinence at End of Treatment Motivational enhancement plus coping skills plus voucher-based incentives Motivational enhancement plus behavioral coping skills therapy Motivational enhancement therapy Budney, A.J. et al., Journal of Consulting and Clinical Psychology, December 2000.

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