Effects of Marijuana On Brain, Body & Behavior Nora D. Volkow, M.D. Director
Marijuana is the Most Commonly Used Illicit Drug In the U.S. Over 111 million Americans have tried it at least once An estimated 2.4 million Americans used it for the first time in 2012 2012 National Survey on Drug Use and Health, SAMHSA, 2013. Tetrahydrocannabinol (THC) Active Ingredient in Marijuana
ADDICTION IS A DEVELOPMENTAL DISEASE it starts in adolescence and childhood Percentage in each age group who develop first-time dependence 1.8% 1.6% 1.4% 1.2% 1.0% 0.8% 0.6% 0.4% 0.2% 0.0% TOBACCO THC ALCOHOL 5 10 15 21 25 30 35 40 45 50 55 60 65 Age Age at tobacco, at alcohol and at cannabis use dependence as per DSM IV NIAAA National Epidemiologic Survey on Alcohol and Related Conditions, 2003.
Percentage of U.S. 12 th Grade Students Reporting Past Month Use of Cigarettes and Marijuana 40 35 30 25 Marijuana 20 15 10 Cigarettes 5 0 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 07 08 09 10 11 12 13 SOURCE: University of Michigan, 2013 Monitoring the Future Study.
Natural and Drug Reinforcers Increase Dopamine in NAc frontal cortex nucleus accumbens VTA/SN Drugs of abuse increase DA in the Nucleus Accumbens, which is believed to trigger the neuroadaptions that result in addiction % of Basal Release % of Basal Release % of Basal Release 1100 1000 900 800 700 600 500 400 300 200 100 0 150 125 AMPHETAMINE 0 1 2 3 4 5 hr MARIJUANA 100 0 20 40 60 80 Tanda, et al, Science 1997. 200 150 100 50 0 Empty Box Feeding FOOD 0 60 120 180 Time (min) Di Chiara et al.
Constituents of MJ and the Cannabinoid System delta-9-tetrahydrocannabinol delta-9-tetrahydrocannabivarin delta-8-tetrahydrocannabinol cannabigerol cannabinol cannabichromene cannabidiol
Cannabinoid Receptors Are Located Throughout the Brain and Regulate: Brain Development Memory and Cognition Motivational Systems & Reward Appetite Immunological Function Reproduction Movement Coordination Pain Regulation & Analgesia.......................................................
Long Term Effects of Marijuana Addiction: About 9% of users may become dependent, 1 in 6 who start use in adolescence, 25-50% of daily users Percent Estimated Prevalence of Dependence Among Users 35 30 25 20 15 10 5 0 32 15 9 17 11 8 5 23 * * * Nonmedical Use Source: Anthony JC et al., 1994
Drug Use Outcomes in Twin Pairs (n =234) Discordant for Cannabis Use Before Age 17 Odds Ratio Source: Lynskey, MT et al., JAMA, 289, pp. 427-433, 2003.
Does marijuana use negatively affect the brain?
Cannabinoid CB1 Receptors in Human Brain are Downregulated in Marijuana Abusers Marijuana Abusers Controls ACC/CBL Van Loere et al., 2007. Hirvonen et al., Mol Psychiatry 2013
Brain abnormalities associated with long-term heavy cannabis use Hippocampus Amygdala L (yellow) and R (blue) amygdala L(red) and R(green) hippocampus morphology and function of hippocampus has been linked to reduced memory performance in heavy cannabis users Hippocampal and amygdalar volumes were smaller in cannabis users than in controls. Yucel et al., Arch Gen Psychiatry. 2008 Jun;65(6):694-701.
Early (<18y) Long-Term Cannabis Use Decreases Axonal Fiber Connectivity Precuneus to splenium Fimbria of hippocampus, hippocampal commissure and Splenium Axonal paths with reduced connectivity (measured with diffusion-weighted MRI) in cannabis users (n=59) than in controls (N=33). Zalesky et al Brain 2012.
Persistent Cannabis Users Show Neuropsychological Decline from Childhood to Midlife Dunedin prospective study of 1037 Ss born 1972/73, Tested for IQ at age 13 and 38y. Tested THC use ages 18, 21, 26, 32 and 38y Change in Full-Scale IQ (in standard deviation units) 0.4 0.2 0-0.2-0.4-0.6 Adolescent Vulnerability 1 Diagnosis 2 Diagnoses 3 Diagnoses -0.8 p=.44 p=.09 p=.02 Cannabis Dependent Before Age 18 (n=17) Not Cannabis Dependent Before Age 18 (n=57) Cannabis Dependent Before Age 18 (n=12) Not Cannabis Dependent Before Age 18 (n=21) Cannabis Dependent Before Age 18 (n=23) Not Cannabis Dependent Before Age 18 (n=14) Source: Meier MH et al., PNAS Early Edition 2012.
Cannabis Use and Later Life Outcomes Are Dose Dependent % welfare dependent (ages 21-25) % Unemployed (ages 21-25) mean personal income in thousands of NZ $ at age 25 % gained university degree by age 25 400+ 300 to 399 200 to 299 100 to 199 1 to 99 Never # of occasions using Cannabis ages 14-21 Number of occasions using Cannabis between ages 14-21 Source: Fergusson and Boden. Addiction, 103, pp. 969-976, 2008.
Average Delta-9 THC Concentration Per Year 14 5000 12 4500 4000 Percentage 10 8 6 3500 3000 2500 2000 Number of Samples n D-9 THC% 4 1500 1000 2 500 0 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 0
Mean Concentrations of THC, Ethanol & Amphetamines In Whole Blood Samples From Drivers Apprehended By The Police Suspected Of Driving Under The Influence THC Amphetamine & Methamphetamine Ethanol Vindenes V et al.,forensic Sci Internati 2013; 226(1 3): 197-201.
Increased Marijuana Treatment Admissions 1993 and 2007 Emergency Department Visits Involving Selected Drugs: 2008 60 50 1993 2007 % of admissions 40 30 20 10 0 Alcohol Cocaine Heroin Marijuana Source: SAMHSA, TEDS 1993 & 2007. Source: SAMHSA, 2008 DAWN.
12 th Graders Past Year Marijuana Use vs. Perceived Risk of Occasional Marijuana Use 100 80 60 40 20 0 75 77 79 81 83 85 87 89 91 93 95 97 99 01 03 05 07 09 11 13 Past Year Use Perceived Risk SOURCE: University of Michigan, 2013 Monitoring the Future Study
New Online Resources For teens and those that care about them Treatment Publication Principles of Adolescent Substance Use Disorder Treatment: A Research Based Guide Outlines thirteen principles and evidence-based approaches for treating adolescent substance use disorders (SUD). Medical School Curriculum The Substance Use Disorder in Adolescents: Screening and Engagement in Primary Care Settings Provides a series of videos demonstrating effective screening techniques. Web interactive Drugs + Your Body: It Isn't Pretty Includes graphics, videos, quizzes and much more on the wide-ranging harmful effects of drugs on the brain and body.
Workshops CADCA 2014 National Forum February 3-6, 2014 Tuesday, February 4, 2014 National Leadership Plenary Session Nora D. Volkow, M.D., Director, NIDA 9 am 10:30 am Potomac Ballroom A-B Thursday, February 6, 2014 Considerations of Culture and Context when Implementing Evidence-Based Prevention Programs: Process, Challenges and Opportunities 9 am 10:15 am Chesapeake J-L The Science of Addiction: Building Resilience from the Brain Up 10:45 am 12:00 Noon Chesapeake 10-12 NIDA thanks CADCA for helping to make it a great success Science Update from NIDA: Spotlight on Marijuana-Related Research 2:45 pm 4:00 pm National Harbor 10-11
CADCA & NIDA are creating an Online Course that is: Research-focused ` How does marijuana affect health and well- being? Brain development Impaired driving Interactive Designed for community problem-solvers Academic performance Click each button for more