December 19, 2018
Cannabis Use During Pregnancy May Increase A Child's Risk of Psychotic Behavior, A Study Found
Sep 23, 2020, 9:36 AM
Crystal Cox/Business Insider
- Cannabis use among pregnant women has doubled in the past 15 years.
- A recent study found cannabis use during pregnancy was associated with adverse childhood outcomes such as ADHD, social problems, and psychotic-like experiences.
- The study authors recommend that doctors and dispensaries discourage pregnant women from using cannabis.
As cannabis becomes more widely accepted in the US, recreational and medical use are becoming more common across the general population — even more so among pregnant women.
Self-reported cannabis use among pregnant women has more than doubled in the past 15 years, increasing from 3.4% to 7% between 2002 and 2017. Among the general population, cannabis use increased by about one-third (from 6.2% to 8.4% of people aged 12 and older) during that same period.
But a recent study suggests that this trend could be harmful to future generations, as cannabis use during pregnancy is associated with adverse childhood outcomes.
The study, published today in JAMA Psychiatry, found that women who used cannabis during pregnancy were more likely to have children with social problems, impulsivity and attention problems, and psychotic-like experiences that can be predictive of disorders like schizophrenia.
"Much of the prior work that has looked at prenatal marijuana exposure has looked at things like infant motor behavior and sleep and birth weight," study author Ryan Bogdan, associate professor of psychological and brain sciences at Washington University St. Louis, told Insider. "There have been relatively few studies that have looked at later outcomes in childhood."
The association was strongest when mothers used cannabis when they already knew they were pregnant
The study data came from the Adolescent Brain and Cognitive Development Study, a national survey of almost 12,000 children. Of that dataset, 655 children were exposed to cannabis prenatally — which could reflect an underestimate, since the data was self-reported.
From there, the authors of the cannabis use study grouped the data into a cohort of children who were exposed before their mothers knew they were pregnant, and those whose mothers continued to use cannabis after they learned they were pregnant. They also ruled out variables such as family history of psychosis, socioeconomic status, and the use of tobacco or alcohol during pregnancy.
With those factors accounted for, there remained an association between child psychopathology and cannabis use after knowledge of pregnancy.
"One of the interesting things about that is that the time that mothers learn they're pregnant in this study was around seven weeks, which roughly corresponds to when endocannabinoid type-1 receptors are first expressed in the brain," Bogdan said.
Those are the receptors that tetrahydrocannabinol, the psychoactive compound in cannabis, binds to, and they develop around six weeks gestation, he explained.
Although the study found an association rather than a causal relationship between cannabis use and childhood outcomes, Bogdan said if there was a causal impact to be explored in future research, it would likely occur after those receptors formed in the fetus.
Based on these findings, pregnant women should not use cannabis
The next step would be to explore the effects of prenatal cannabis exposure on childhood development in animal studies, or to compare sibling relationships where the mother used cannabis while pregnant with one child but not the other, Bogdan said.
In the meantime, he recommends that pregnant women do not use cannabis, and that doctors and dispensaries discourage cannabis use during pregnancy. This is consistent with advisories from the US Surgeon General and the American College of Obstetricians and Gynecologists.
Bogdan said he's particularly hopeful that the study results will drive women who used cannabis before learning of their pregnancies to change their habits after the six-week mark.
"I think we have a tendency to say, 'Well, the fetus is already exposed, so I might as well continue using,' but this suggests that there would be additional basis to stop," Bogdan said.
W. O. Belfield, Jr.