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Teaching about Marijuana & the Brain VACALC Workshop 3-6-2012 Adrienne Keller [ Susie Bruce ] University of Virginia. Primary Goals. Share some of what we teach our ADAPT students Share some of the best web resources we’ve found – watch for the mice!
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Teaching about Marijuana & the Brain VACALC Workshop 3-6-2012 Adrienne Keller [Susie Bruce] University of Virginia
Primary Goals • Share some of what we teach our ADAPT students • Share some of the best web resources we’ve found – watch for the mice! • Caveat: We take several 75 minute long classes to cover this material.
Before the classes on marijuana, we have already covered THE BRAIN!
Cortex Limbic system Brain stem
Brain Functioning: It’s all about communication
Dense Pathways in the Brain hyperlink
Neurotransmitters • natural chemicals associated with emotions • Over 100 chemicals in combinations • Some important ones for response to drugs • Endorphins/ Enkephalins • Serotonin • Norepinephrine • Dopamine • Acetylcholine
Neurotransmitters can be… hyperlink Excitatory Inhibitory
Effect of “Exogenous” Drugs on Neurons • Neurons stop production of the natural neurotransmitter • As the body breaks down chemicals from drug, there are no natural chemicals to replace them • Crash/Craving
What is drug addiction? • a chronic, relapsing brain disease that affects: • Brain structure • How the brain works • characterized by: • compulsive drug seeking • use, despite harmful consequences • harmful behaviors
hyperlink What do mice know?
For more specifics in words: http://science-education.nih.gov/supplements/nih2/addiction/guide/lesson3-1.htm Illustration of cocaine’s effect on dopamine transport: http://science-education.nih.gov/supplements/nih2/addiction/activities/lesson3_cocaine.htm
hyperlink Pathways to the Brain
"Drug addiction is a brain disease that can be treated." Nora D. Volkow, M.D., DirectorNational Institute on Drug Abuse
With that background, we’re then ready to tackle Marijuana & the brain
Marijuana History • One of the oldest cultivated plants • In the U.S. since 1720 for: rope, twine, sail cloth, oil for soap & paint • 1937 Marijuana Tax Act • 1950s & 60s “Beatnik” &“hippie” cultures • 1970 Controlled Substances Act: • Marijuana is Schedule 1 drug • 1972 Isolated psychoactive chemical • 1978 Science: cannabis is addictive
Marijuana: • Cannibas sativa • Genus is cannibas; species is sativa • Native to Asia • Used for centuries for fiber (hemp), herbal remedies and for their psychoactive properties. • Psychoactive substance is a cannabinoid: tetra/hydro/canna/binol (THC) tetrahydrocannabinol
61 Cannabinoids Aldehydes Phenols Carcinogens Carbon monoxide 50-70% more carcinogenic hydrocarbons than tobacco What’s in marijuana smoke? Courtesy of Linda Hancock, VCU & NIDA Research Report
Comparison of RISK CIGARETTESMARIJUANA More consumed Less consumed Usually filtered Often unfiltered Less tar More Tar (more oil) 3-4 joints per day are as damaging as 15-20 cigarettes per day. Courtesy of Linda Hancock, VCU
Pot Potency Increasing Due to selective breeding 1975 - 0.74% THC 2009 - 13.01% THC >10 fold increase Higher risk for tolerance & addiction Potency Monitoring Project, Report 104, 2009: http://www.whitehousedrugpolicy.gov/publications/pdf/mpmp_report_104.pdf
Remember tetrahydrocannabinol? A closer look at THC
THC IS FAT SOLUBLE… So what?
Our bodies make natural cannabinoids: • Most important is anandamide • Affects many mental & physical processes • Memory and perception • Fine motor coordination • Pain sensation • Immunity to disease • Reproduction
Source: http://cannagraphic.com/cannabis/effects-of-marijuana-on-the-brain-infographic/
Common student questions: • Does marijuana cause short term impairment? • Does marijuana cause lingering impairment? • Are there long term effects from using marijuana? • Is marijuana addictive? • Can I beat the pee test?
CAUTIONS about the Research • Mainly animal studies. (Huge doses are used compared to doses used in young adults.) • Human studies primarily focus on healthy youth and short term effects. • Very few long term effect studies exist. • Research subjects often used other drugs in addition to marijuana. • This is a topic laden with emotion and political agendas. Courtesy of Linda Hancock, VCU
Time distortion • Trouble shifting attention • Impaired short-term memory • Lower verbal IQ • Impaired executive functioning
Short-term typical impairment is roughly equal to a .08 BAC In roadside sobriety tests • 90 min. after smoking, 94% failed • 2.5 hrs. after smoking, 60% failed
Airline pilots using flight simulators… • Skills needed to fly safely remained seriously impaired 24 hours later • But only 1 in 7 recognized the continued impairment.
Marijuana and Car Crashes Cannabis use is associated with a 3X greater risk of being responsible for a fatal crash. As # of joints smoked goes up, likelihood of causing a fatal crash increases
Cognitive impairment can last at least 28 days after stopping use • Very heavy users: impairment than light users • Average use = 4.8 years • Average age = 22 years • Cognitive deficits after 28 days abstinence: • verbal and visual memory, • visual perception • psychomotor speed, • manual dexterity • executive functioning Jill Schlabig Williams, NIDA Notes, Vol. 18, #5
Long-term Effects • A study of 450 people found that people who smoke marijuana frequently but do not smoke tobacco • have more health problems • miss more days of work than nonsmokers • marijuana smoking doubles or triples the risk of developing cancer of the head or neck NIDA Research Report
hyperlink Does marijuana affect brain structure? An expert opinion