Marijuana and the Teen Brain What parents need

Marijuana and the Teen Brain: What parents need to know Leslie Green, LICSW Clinical Social Worker Shannon Mountain-Ray, LICSW Clinical Director of Social Work Adolescent Substance Abuse Program (ASAP) Division of Developmental Medicine Boston Children’s Hospital

Objectives • Recent findings from MWHS • Describe adolescent brain development • Explain why we call addiction a “brain disease” • Present the impact of marijuana use on the developing adolescent brain and other risks associated with adolescent marijuana use

The Teen Brain What is going on in there? Source: US News & World Report, 2005 8

What We Now Know • Adolescence is a critical period in brain development. • The brain is still developing until approximately age 24 or 25 Slide courtesy of Ken Winters, Ph. D. 9

Critical Period Is a “window” in brain development when a part of the brain: • develops rapidly • is highly sensitive to being shaped by environmental experiences 10

Brain cells (Neurons)

Construction Ahead BLOSSOMING: Until about ages 10 -12, the brain undergoes rapid growth, including: • Neuron numbers increasing • Neurons getting bushier • Neuron connections increasing Slide courtesy of Ken Winters, Ph. D. 12

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Construction Ahead Around age 12, neuronal growth starts to undergo pruning, following the principle of “use it or lose it. ” Slide courtesy of Ken Winters, Ph. D. 14

Construction Ahead Along with pruning, myelin starts to cover axons and then thicken. The myelin sheaths help action potential travel 100 times faster. Slide courtesy of Ken Winters, Ph. D. 16

The Brain’s Info Superhighway: Myelinated axons = White Matter Tracts Source: Gordon J. Harris, Ph. D. 17

Construction Ahead Result of Pruning and Myelination: Fewer but faster connections in the brain. Slide courtesy of Ken Winters, Ph. D. 18

How the Brain Develops Front Back Parietal Lobe Frontal Lobe Prefrontal Cortex Nucleus Accumbens Occipital Lobe Temporal Lobe Brain Stem Hippocampus Cerebellum Amygdala 19

Brain Maturation Nucleus Accumbens (highly active in adolescence) • Pleasure center • Active during pleasurable activities, including feeding, sex, and drug use • Plays a major role in addiction Prefrontal Cortex (matures late adolescence or early adulthood) Impulse control Decision-making Organizing and planning Abstract thought, rational thinking • Attention, focus • Working memory • •

Addiction is a Brain Disease

The Reward Pathway Source: NIDA Ventral-Tegmental Area

The Common Pathway to Pleasure Dopamine, a neurotransmitter, works in the pleasure center in the middle of your brain. Once you’ve had a “feel good” experience, your brain builds new paths or a shortcut.

marijuana

Key Points 1. Adolescence is an important “window” of opportunity and sensitivity for the brain, particularly for developing brain connectivity. 2. How the brain is used during adolescence, and what it is exposed to, will have life-long effects.

Key Points 3. Due to the stage of brain development in adolescence, teens are more susceptible to the addictive effects of substance use.

Marijuana and the Teen Brain 27

What is in Marijuana? Contains many cannabinoid chemicals: • • delta-9 -tetrahydrocannabinol (THC) delta-8 -tetrahydrocannabinol cannabidiol cannabinol cannabichromene cannabigerol Etc. Source: Mechoulam R, Hanus L, The cannabinoid system from the point of view of a chemist. In 28 Marijuana and Madness. ed. Castle, Murray. Cambridge University Press, 2004

The Brain’s “Endocannabinoid” System “Endo” means “within”

Endocannabionoid System Functions • The neuron’s “volume control” system: dials down neuron activity when too strong • Regulates levels of neurotransmitters that affect pleasure, mood, pain, appetite, motivation, memory (e. g. , dopamine, glutamate, endorphins, serotonin, GABA)

Source: NIDA

With Anadamide: With Marijuana: Dopamine release

THC vs. Anandamide • Both dial down neuron activity to change neurotransmitter release • THC has a MUCH STRONGER, LONGER effect than anandamide on brain cells • THC interferes with cell function and growth

THC Binding Sites Front Source: NIDA Back 34

Marijuana Effects on Teen Memory and Thinking

Hippocampus

Marijuana Use and Change in IQ Source: Meier et al. Proceedings of the National Academy of Sciences. 2012. Available at: www. pnas. org/cgi/doi/10. 1073/pnas. 1206820109

The Dunedin Study (New Zealand) (N=1, 037) 13 yrs (Pre-initiation) 1 18 yrs 2 21 yrs 3 Assessment ages Source: Meier et al. PNAS, 2012 32 yrs 38 yrs 4 5

Average IQ at Ages 13 to 38 by Marijuana Use 13 yrs old 99, 8 Never used marijuana 99, 7 Used marijuana 3+ years

Average IQ at Ages 13 to 38 by Marijuana Use 13 yrs old 99, 8 100, 6 38 yrs old 99, 7 93, 6 Never used marijuana Used marijuana 3+ years

Marijuana Use and School Drop-out Source: Lynskey et al. Addiction, 2003.

Increased Odds of Dropping Out of HS by Age of Starting Weekly MJ Use 6 x Grade 10 Grade 11 Grade 12 2 x 1 x 1 2 3 4 5 6

Marijuana and Mental Illness

Studies show regular marijuana use during adolescence risk 2 to 7 times of developing psychosis, schizophrenia, anxiety, and depression. Source: Malone DT et al. Adolescent cannabis use and psychosis: epidemiology and neurodevelopmental models. Brit J Pharmacol. 2010; 160: 511 -522 44

The Brain’s Info Superhighway: Myelinated axons = White Matter Tracts Source: Gordon J. Harris, Ph. D. 45

Similar altered white matter structure found in the brains of people dx with schizophrenia and teen marijuana users Bava S, Frank LR, Mc. Queeny T, Schweinsburg BC, Schweinsburg AD, Tapert SF. Altered white matter microstructure in adolescent substance users. Psychiatry Research Neuroimaging. 2009; 173: 228 -237.

Corpus callosum damage in daily marijuana users Non-user Daily user Source: Arnone D, Barrick TR, Chengappa S et al. Corpus callosum damage in heavy marijuana use: Preliminary evidence from diffusion tensor tractography and tract-based spatial statistics. Neuro. Image, 2008; 41: 1067 -1074

STUDIES Meier et al. , 2012 Pope et al. , 2003 Ehrenreich et al. , 1999 Huestegge et al. , 2002 Fontes et al. , 2011 Cognitive Gruber et al. , 2012 Jager et al. , 2010 Brain Function Effects IQ attention visual search executive functioning Solowij et al. , 2012 executive functioning Churchwell et al. , 2010 Gruber et al. , 2011 impulsivity Lopez-Larson et al. , 2011 Wilson et al. , 2000 Becker et al. , 2010 a Brain Structure prefrontal cortex volume white matter integrity in prefrontal cortex thickness total gray matter, prefrontal cortex activity during working memory task anterior cingulate activity during inhibition task prefrontal cortex activity during in working memory

Marijuana and Driving

Brain regions affected by THC Source: NIDA

Marijuana and Driving Studies of performance show that THC impairs attention, working memory, coordination, reaction time, and visual perception Source: Castle D, Solowij N. Acute and subacute psychomimetic effects of cannabis in humans. In: Castle D, Murray R, eds. Marijuana and Madness. Cambridge, UK: Cambridge University Press; 2004: 41 -53.

What else is affected by marijuana?

Reproductive/Growth Hormones • Marijuana affects glands, organs and hormones involved in overall growth, pubertal development, and energy levels • Can lower fertility of males and females through lowered sperm count and egg damage • Increases risk for testicular cancer Source: Wenger T, Croix D, Tramu G. The effect of chronic prepubertal administration of marijuana (delta-9 -tetrahydrocannabinol) on the onset of puberty and the post-pubertal reproductive functions in female rats. Biology of Reproduction. 1988; 39: 540 -545.

Avg. % THC Content among Confiscated Cannabis Products in U. S. (1993 -2012)* 14% 12% 10% 8% 6% 4% <4% 2% 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 0% *Source: El. Sohly MA. Potency Monitoring Project Quarterly Report #123. U of Mississippi, 2014

THC Content Increase => Increase in Adverse Effects: • Paranoia • Anxiety and panic • Hallucinations • Hyperemesis • Erratic mood swings • Aggressive behavior Source: National Drug Abuse Warning Network, 2011

First death in Colorado after legalized recreational marijuana • 19 year-old Levy Thamba-Pongi, college student visiting on Spring Break • Died March 11, 2014 • Jumped out 4 th floor hotel window after eating cookie with 65 mg of THC

Perceived Risk of Harm and th Marijuana Use, U. S. 12 graders: 1975 -2011 Great Risk of Harm 90% Past Month Use Perceived risk is at a nearly historic low! 80% 70% 60% 50% 39. 5% 40% 30% 22. 7% 20% Source: National Monitoring the Future Survey, 2013 2011 2009 2007 2005 2003 2001 1999 1997 1995 1993 1991 1989 1987 1985 1983 1981 1979 1977 0% 1975 10%

Percent of 12 th Graders Reporting Using Substance in Lifetime, 2000 -2013 90 80 Alcohol 70 60 Tobacco 50 40 Marijuana 30 Source: National Monitoring the Future Survey, 2013 2012 2011 2010 2009 2008 2007 2006 2005 2004 2003 2002 2001 2000 20

Marijuana Legalization (2014) Source: http: //www. governing. com/gov-data/safety -justice/state-marijuana-laws-map-medicalrecreational. html (18 states) (2)

Percent Using Marijuana in Past Month, Ages 12 -17, by State VT NH MA RI CO DC MT OR WA CA NM ME AK CT NV HI DE MI AZ NY NJ NC IL ID WV MO VA PA OK OH MN FL IN GA WI SC KY TX MS KS AL TN NE MD IA AR SD LA WY ND UT States with Legalized Marijuana 0% 1% 2% 3% 4% 5% 6% 7% 8% Source: National Survey on Drug Use and Health, 2010 -2011 9% 10% 11% 12% 13% 14% 15%

Take-Home Points 1. The teen years are a time of tremendous opportunity and risk for the brain 2. The endocannabinoid system is important for maintaining brain health and proper development, and THC interferes with its proper functioning! 3. Regular marijuana use in adolescence may have lasting effects on memory and IQ 61

Take-Home Points 4. Today’s marijuana is a much more potent than 20 years ago 5. Marijuana use increases risk for car crashes 6. The risk of serious mental illness is 2 -7 times greater for those starting marijuana use during adolescence 7. It is not safe in any capacity – out of the home, in the home, etc. 62

Funding provided by the American Medical Foundation Healthy Living Grants Program Thank you © Boston Children’s Hospital 2012. All Rights Reserved. For permissions contact SBIRT project manager at www. Ce. ASAR. org.

Acknowledgements • John Knight • Sharon Levy • Ximena Sanchez. Samper • Patricia Schram • Miriam Schizer • Wesley Boyd • Susan Kiley • Shari Van. Hook • • Leslie Green Julie Hansen Lon Sherritt Marianne Pugatch Celeste Wilson Roman Pavlyuk Sion Harris Rosemary Zeimnik

Q&A