Children whose mothers use marijuana may try it at a younger age

A marijunana dispensary in Glenwood Springs, Colorado.

For immediate release: September 24, 2018

Boston, MA – Children whose mothers use marijuana are more likely to start their own marijuana use an average of two years earlier than children whose mothers don’t use the drug, according to a new study from Harvard T.H. Chan School of Public Health.

The study was published September 24, 2018 in the American Journal of Preventive Medicine.

“Beginning marijuana use at a young age has been linked with negative cognitive and behavioral consequences,” said Natasha Sokol, who led the study while a doctoral student at Harvard Chan School and is now a postdoctoral research fellow at Brown University School of Public Health’s Center for Alcohol and Addiction Studies. “In a shifting regulatory environment in the U.S. in which the visibility and acceptability of adult marijuana use is expected to increase, it’s important to better understand how these changes may impact children’s early marijuana use so that we can better identify at-risk youth and implement effective prevention strategies.”

Prohibiting marijuana isn’t necessarily consistent with public health goals, according to the study authors. For example, marijuana has recognized therapeutic benefits for a number of health conditions, and may serve as a safer alternative to opioids. In addition, more than half of all drug arrests in the U.S. are marijuana-related and are a major driver of racial disparities in arrest and incarceration.

But in children who begin use at a young age, marijuana has been linked with negative consequences such as impairments in concentration and decision-making, increased impulsivity, and reductions in IQ. The younger a child is when he or she begins using marijuana, the more severe the effects, studies have suggested. Therefore, delaying marijuana initiation may be an important public health goal, the authors said.

Using data from the National Longitudinal Survey of Youth 1979 and Child and Young Adults, the new study assessed the timing and extent of marijuana use and initiation among 4,440 children and 2,586 mothers. Researchers tested for the effect of a mother’s marijuana use between a child’s birth and age 12 on that child’s subsequent risk of marijuana initiation, controlling for factors related to the child’s early life behavior and cognition and on the family’s socioeconomic position and social environment.

The study found that 2,983 children (67.2%) and 1,053 mothers (35.3%) self-identified as marijuana users. Children whose mothers used marijuana were at increased risk for starting marijuana use prior to age 17, and they began using at a median age of 16, compared with age 18 for children whose mothers didn’t use the drug. The association was slightly stronger among non-Hispanic non-black children.

One limitation of the study was that it did not measure whether children were aware of their mothers’ marijuana use. The study also lacked data on the frequency and severity of mothers’ marijuana use.

“Although more research is needed, physicians who prescribe marijuana might consider educating parents who use the drug about the potential dangers of early marijuana use among their children, and provide information and preventive strategies to delay such use,” said Vaughan Rees, lecturer on social and behavioral sciences and director of Harvard Chan School’s Center for Global Tobacco Control.

Other Harvard Chan School authors included Cassandra Okechukwu, Jarvis Chen, and S.V. Subramanian.

Funding for the study came from the National Institute of Drug Abuse (NIDA) Ruth L. Kirschstein National Research Service Award Individual Predoctoral Fellowship #1F31DA039586-01 and NIDA grant #R03DA038697.

“Maternal Cannabis Use During a Child’s Lifetime Associated With Earlier Initiation,” Natasha A. Sokol, Cassandra A. Okechukwu, Jarvis T. Chen, S.V. Subramanian, and Vaughan W. Rees, American Journal of Preventive Medicine, September 24, 2018, doi: 10.1016/j.amepre.2018.06.023

photo: iStock

Visit the Harvard Chan School website for the latest newspress releases, and multimedia offerings.

For more information:

Chris Sweeney


Harvard T.H. Chan School of Public Health brings together dedicated experts from many disciplines to educate new generations of global health leaders and produce powerful ideas that improve the lives and health of people everywhere. As a community of leading scientists, educators, and students, we work together to take innovative ideas from the laboratory to people’s lives—not only making scientific breakthroughs, but also working to change individual behaviors, public policies, and health care practices. Each year, more than 400 faculty members at Harvard Chan School teach 1,000-plus full-time students from around the world and train thousands more through online and executive education courses. Founded in 1913 as the Harvard-MIT School of Health Officers, the School is recognized as America’s oldest professional training program in public health.