U.S. Surgeon General’s Advisory: Marijuana Use and the Developing Brain

Steven Barto, B.S., Psych.

I am reposting this information from a link to the U.S. Department of Health and Human Services (HHS.gov) provided by the National Institute on Drug Abuse (NIDA) website.

I, Surgeon General Jerome Adams, am emphasizing the importance of protecting our Nation from the health risks of marijuana use in adolescence and during pregnancy. Recent increases in access to marijuana and in its potency, along with misperceptions of safety of marijuana endanger our most precious resource, our nation’s youth.

Background

Marijuana, or cannabis, is the most commonly used illicit drug in the United States. It acts by binding to cannabinoid receptors in the brain to produce a variety of effects, including euphoria, intoxication, and memory and motor impairments. These same cannabinoid receptors are also critical for brain development. They are part of the endocannabinoid system, which impacts the formation of brain circuits important for decision making, mood and responding to stress.

Marijuana and its related products are widely available in multiple forms. These products can be eaten, drunk, smoked, and vaped. Marijuana contains varying levels of delta-9-tetrahydrocannabinol (THC), the component responsible for euphoria and intoxication, and cannabidiol (CBD). While CBD is not intoxicating and does not lead to addiction, its long-term effects are largely unknown, and most CBD products are untested and of uncertain purity.

Marijuana has changed over time. The marijuana available today is much stronger than previous versions. The THC concentration in commonly cultivated marijuana plants has increased three-fold between 1995 and 2014 (4% and 12% respectively). Marijuana available in dispensaries in some states has average concentrations of THC between 17.7% and 23.2%. Concentrated products, commonly known as dabs or waxes, are far more widely available to recreational users today and may contain between 23.7% and 75.9% THC.

The risks of physical dependence, addiction, and other negative consequences increase with exposure to high concentrations of THC and the younger the age of initiation. Higher doses of THC are more likely to produce anxiety, agitation, paranoia, and psychosis. Edible marijuana takes time to absorb and to produce its effects, increasing the risk of unintentional overdose, as well as accidental ingestion by children and adolescents. In addition, chronic users of marijuana with a high THC content are at risk for developing a condition known as cannabinoid hyperemesis syndrome, which is marked by severe cycles of nausea and vomiting.

This advisory is intended to raise awareness of the known and potential harms to developing brains, posed by the increasing availability of highly potent marijuana in multiple, concentrated forms. These harms are costly to individuals and to our society, impacting mental health and educational achievement and raising the risks of addiction and misuse of other substances.  Additionally, marijuana use remains illegal for youth under state law in all states; normalization of its use raises the potential for criminal consequences in this population. In addition to the health risks posed by marijuana use, sale or possession of marijuana remains illegal under federal law notwithstanding some state laws to the contrary.

Marijuana Use during Pregnancy

Pregnant women use marijuana more than any other illicit drug. In a national survey, marijuana use in the past month among pregnant women doubled (3.4% to 7%) between 2002 and 2017. In a study conducted in a large health system, marijuana use rose by 69% (4.2% to 7.1%) between 2009 and 2016 among pregnant women. Alarmingly, many retail dispensaries recommend marijuana to pregnant women for morning sickness.

Marijuana use during pregnancy can affect the developing fetus.

  • THC can enter the fetal brain from the mother’s bloodstream.
  • It may disrupt the endocannabinoid system, which is important for a healthy pregnancy and fetal brain development.
  • Studies have shown that marijuana use in pregnancy is associated with adverse outcomes, including lower birth weight.
  • The Colorado Pregnancy Risk Assessment Monitoring System reported that maternal marijuana use was associated with a 50% increased risk of low birth weight regardless of maternal age, race, ethnicity, education, and tobacco use.

The American College of Obstetricians and Gynecologists holds that “[w]omen who are pregnant or contemplating pregnancy should be encouraged to discontinue marijuana use. Women reporting marijuana use should be counseled about concerns regarding potential adverse health consequences of continued use during pregnancy”. In 2018, the American Academy of Pediatrics recommended that “…it is important to advise all adolescents and young women that if they become pregnant, marijuana should not be used during pregnancy.”

Maternal marijuana use may still be dangerous to the baby after birth. THC has been found in breast milk for up to six days after the last recorded use. It may affect the newborn’s brain development and result in hyperactivity, poor cognitive function, and other long-term consequences. Additionally, marijuana smoke contains many of the same harmful components as tobacco smoke. No one should smoke marijuana or tobacco around a baby.

Marijuana Use during Adolescence

Marijuana is also commonly used by adolescents, second only to alcohol. In 2017, approximately 9.2 million youth aged 12 to 25 reported marijuana use in the past month and 29% more young adults aged 18-25 started using marijuana. In addition, high school students’ perception of the harm from regular marijuana use has been steadily declining over the last decade. During this same period, a number of states have legalized adult use of marijuana for medicinal or recreational purposes, while it remains illegal under federal law. The legalization movement may be impacting youth perception of harm from marijuana. 

The human brain continues to develop from before birth into the mid-20s and is vulnerable to the effects of addictive substances. Frequent marijuana use during adolescence is associated with:

  • Changes in the areas of the brain involved in attention, memory, decision-making, and motivation. Deficits in attention and memory have been detected in marijuana-using teens even after a month of abstinence.
  • Impaired learning in adolescents. Chronic use is linked to declines in IQ, school performance that jeopardizes professional and social achievements, and life satisfaction.
  • Increased rates of school absence and drop-out, as well as suicide attempts.

Risk for and early onset of psychotic disorders, such as schizophrenia. The risk for psychotic disorders increases with frequency of use, potency of the marijuana product, and as the age at first use decreases. 

  • Other substance use. In 2017, teens 12-17 reporting frequent use of marijuana showed a 130% greater likelihood of misusing opioids.

Marijuana’s increasingly widespread availability in multiple and highly potent forms, coupled with a false and dangerous perception of safety among youth, merits a nationwide call to action. 

You Can Take Action

No amount of marijuana use during pregnancy or adolescence is known to be safe. Until and unless more is known about the long-term impact, the safest choice for pregnant women and adolescents is not to use marijuana.  Pregnant women and youth–and those who love them–need the facts and resources to support healthy decisions. It is critical to educate women and youth, as well as family members, school officials, state and local leaders, and health professionals, about the risks of marijuana, particularly as more states contemplate legalization.

Science-based messaging campaigns and targeted prevention programming are urgently needed to ensure that risks are clearly communicated and amplified by local, state, and national organizations. Clinicians can help by asking about marijuana use, informing mothers-to-be, new mothers, young people, and those vulnerable to psychotic disorders, of the risks. Clinicians can also prescribe safe, effective, and FDA-approved treatments for nausea, depression, and pain during pregnancy. Further research is needed to understand all the impacts of THC on the developing brain, but we know enough now to warrant concern and action. Everyone has a role in protecting our young people from the risks of marijuana.

Prenatal and Early Childhood Brain Development in Mom’s Using Drugs

NIDA Banner Science of Abuse and Addiction.png

From the blog of Dr. Nora Volkow
Director, National Institute on Drug Abuse
March 11, 2019

The National Institutes of Health HEAL (Helping to End Addiction Long-Term) Initiative, which was launched last April, will support a wide range of studies aimed at improving prevention and treatment strategies for opioid use disorder and pain, including efforts to enhance treatments for infants born with Neonatal Abstinence Syndrome/Neonatal Opioid Withdrawal Syndrome. Specifically, HEAL funds will help support an ambitious longitudinal study—The HEALthy Brain and Child Development (HBCD) Study—co-funded by NIDA and several other NIH institutes and offices, to better understand the impact of early exposure to opioids, other substances, and social stressors on brain development in children.

The HBCD study will follow a large population of children from the prenatal period to age 10 and utilize some of the same assessment methods and imaging technologies used in the 10-year Adolescent Brain Cognitive Behavior (ABCD) study. HBCD is expected to enroll women during their second trimester of pregnancy or after birth of their baby. The study will gather data on potentially important factors about their environment, including drug and alcohol use, and follow them and their children over the subsequent decade.

The potential fruits of a longitudinal cohort study of this magnitude will include much new knowledge about the effects of opioids and other substance exposures during fetal development.  It will also yield a better understanding of the effects of genes that are driving brain development. The study additionally will look at many other exposures, including social interactions, environmental toxins, nutrition, and physical activity. Medicine has thus far lacked detailed baseline standards of normative brain development in childhood, and HBCD will help produce such standards. The information gained from the study will create an invaluable reference for pediatricians, pediatric neurologists, and psychiatrists.

The ABCD study recently accomplished its baseline recruitment of close to 12,000 nine- and ten-year-olds, and already the data gathered from the initial neuro-imaging is yielding interesting findings, such as associations between neuro-development and screen time. Likewise, the HBCD study will gather a rich data set that will be freely available to the wider research community to answer a wide range of research questions. For example, researchers can use the data to investigate how the human brain develops and characteristics that might be associated with the early manifestations of brain diseases, as well as those [with an] underlying resilience to adverse environments. As the data are being collected, they will be released so that discoveries can start well before the completion of these 10-year prospective studies. 

As with ABCD, the HBCD study will have multiple research sites across the country to ensure the study population is representative of the larger population, including all ethnic groups and demographics and even including women who use opioids. Exposure to many substances in the womb or through breast milk may have significant developmental consequences, and a study of this magnitude will greatly clarify the effects of prenatal and early opioid exposure on children. It will also greatly increase our understanding of the developmental consequences of environmental stressors like neglect, abuse, economic uncertainty, and the influence of parental opioid and other drug use during the post-natal period.

As you might imagine, there are many potential challenges to conducting regular brain imaging on young children—being able to remain still in MRI scanners is just one of them. There are also special legal and ethical challenges involved in recruiting and studying opioid-using mothers. In September and October of last year, NIDA in partnership with other NIH Institutes and Centers, hosted two expert panel meetings to discuss, respectively, the methodological challenges of studying neuro-development in children and recruitment and retention of high-risk populations in the study, including bio-ethical questions.

Based on input received during these expert panel meeting, it was determined that before soliciting grant proposals for the HBCD study per se, an initial planning period would be necessary. Thus, NIDA along with the National Institute on Alcohol Abuse and Alcoholism (NIAAA), the National Institute of Child Health and Human Development (NICHD), the National Institute of Environmental Health Sciences (NIEHS), the National Institute of Mental Health (NIMH), the National Institute of Neurological Disorders and Stroke (NINDS), the National Institute on Minority Health and Health Disparities (NIMHD), the Office of Research on Women’s Health (ORWH), and the Office of Behavioral and Social Sciences Research (OBSSR) issued two funding opportunity announcements, one for individual research sites and one for linked, collaborative applications.

The planning grants will be awarded for a period of 18 months, during which time we expect to determine many critical facets of the experimental design. These include how to conduct neuro-imaging in prenatal and early postnatal stages, how to address the legal challenges associated with recruiting opioid- (and other drug-) using participants (which vary by state), how to form partnerships with state agencies and substance use treatment programs, how to retain the mothers in the study, and other practical and ethical issues. Applications are due in the last week of March, 2019. Researchers interested in applying for one of these grants can find more information on RFA-DA-19-029 and RFA-DA-19-036 from grants.nih.gov.

It is a very exciting time for all the sciences that study child health, human development, and the roots of mental health and psychiatric and neurological illnesses. We now have the tools to characterize human brain development in the transition from infancy into adulthood, a time when many of the medical conditions that afflict us later in life originate. The data from the HBCD study will ultimately lead to scientific solutions to addiction, pointing the way to new prevention and treatment interventions and thereby reducing the impact of opioid and other substance use disorders on American families.