Marijuana use during pregnancy may increase the risk of psychosis in children

Pregnant women who use cannabis may slightly increase the risk that their unborn child will develop psychosis later in life, suggests a new research from Washington University in St. Louis.

"Our research shows that prenatal exposure to marijuana after the mother experienced pregnancy is badociated with a slight increase in susceptibility to psychoses in mid-to-early childhood or around the age of 10. years, "said Jeremy Fine, an undergraduate student in Psychology and Brain Sciences and Science at the University of Washington. and the main author of the study.

The findings of this study follow several national studies on the dramatic increase in marijuana use by pregnant women, including a study conducted in 2018 by the Washington University School of Medicine in St. Louis, that consumption marijuana in the last month among pregnant women in the United States had increased. 75% between 2002 (2.85%) and 2016 (4.98%).

While more and more states are legalizing the medical and recreational use of cannabis, other reports suggest that many clinics for marijuana generally suggest that cannabis constitutes a natural treatment for nausea-related to pregnancy.

This latest study, published March 27 in the newspaper JAMA Psychiatry, suggests that pregnant women should be discouraged from using cannabis at any time during their pregnancy because little is known about its effects on health.

But his findings also raise new concerns that prenatal cannabis exposure may be at increased risk after the fetal brain begins to develop an endocannabinoid receptor system, which is part of the naturally occurring neurotransmitter network that allows the cannabis to touch the brain.

"One possible explanation for the discovery of an increased risk of psychosis related to marijuana use after, but not before, knowledge of pregnancy is that the endocannabinoid receptor system might not be in place for the first few weeks of pregnancy, "said Ryan Bogdan, badociate professor of psychology. & brain sciences and lead author of the article. "Prenatal exposure to cannabis may be badociated with a subsequent predisposition to psychosis in offspring only when there is sufficient expression of endocannabinoid type 1 fetal receptors, which may not occur before many mothers learned that they were pregnant. "

Bogdan, who heads the BRAIN lab at the University of Washington where the research took place, said that these latest findings support other basic research suggesting that endocannabinoid signaling could contribute to processes, such as neurogenesis and neural migration, which play an important role in the early development of brain structure. and connections.

"This study raises the intriguing possibility that there are windows of development in which exposure to cannabis could increase the risk of psychosis," he said.

Tetrahydrocannabinol (THC), which is the main psychoactive component of marijuana, mimics the endocannabinoids of our body and binds to the endocannabinoid receptors to exert its effects. Various studies have confirmed that THC crosses the placental barrier to access the developing fetus.

"Data from rodent studies suggest that the type 1 endocannabinoid receptor, through which the psychoactive effects of THC occur largely, is expressed only until the the equivalent of 5-6 weeks of human gestation, "said Fine. "Since the mothers in our study averaged their pregnancy at 7.7 weeks, it is likely that no impact of THC on the risk of psychosis will occur until enough endocannabinoid receptors are present. type 1 be expressed. "

The conclusions of the BRAIN laboratory are based on data from the ABCD (Adolescent Brain Cognitive Development) study, an ongoing longitudinal study on child health and brain development, with data collection sites. data throughout the country. They used data from the initial release of ABCD baseline data, which included survey responses from 3,774 mothers for marijuana use in 3,926 pregnancies. The risk of psychosis in 4,361 children born of these pregnancies between 2005 and 2008 was measured with the help of a questionnaire administered to children aged 8.9 to 11 years.

Of the 4,361 children sampled in this study, 201 (4.61%) were reportedly exposed to marijuana prior to birth. Of these, 138 were exposed only before the mothers realized that they were pregnant; two were exposed only after the mother learned that she was pregnant.

Bogdan and his co-authors acknowledge that the study has many limitations, including the small sample of prenatal progeny exposed to cannabis; potential underreporting of maternal use during pregnancy; inaccurate data on the timing, quantity, frequency and potency of cannabis exposure; lack of data indicating whether predisposition to child psychosis is badociated with conversion to psychosis and lack of data on some potential confounding factors, such as maternal stress and genetic risk of psychosis in parents.

"Our research is correlational and therefore does not allow conclusions to be drawn from causality," said Allison Moreau, co-author of the study and a graduate student in psychology at the University of Washington. "However, the link between prenatal exposure to marijuana after the mother's knowledge of pregnancy was badociated with a predisposition to offspring psychosis after taking into account potentially confounding variables – such as – increases the likelihood that prenatal exposure to cannabis may contribute to a low risk of increasing psychotic responsibility in children. "

The study provides further evidence that pregnant women should think twice before considering cannabis use during pregnancy.

"Given the increasing availability and power of cannabis, as well as the increasing public perception of its safe use, it is essential to conduct additional research to understand the negative consequences and potential benefits of cannabis." cannabis throughout development and how these badociations may occur. " Bogdan said. "In the meantime, evidence that prenatal marijuana use is badociated with a slight increase in the susceptibility to psychosis in children suggests that marijuana use during pregnancy should be discouraged until the time of pregnancy. we know more. "