Pregnant women who use cannabis may slightly increase the risk their unborn child will develop psychosis later in life, suggests new research from Washington University in St. Louis.
“Our research shows that prenatal marijuana exposure after maternal knowledge of pregnancy is associated with a small increase in psychosis proneness during middle childhood or about age 10,” said Jeremy Fine, an undergraduate majoring in psychological and brain sciences in Arts & Sciences at Washington University and the study’s lead author.
The findings come on the heels of several national studies documenting a dramatic increase in marijuana usage by pregnant women, including a 2018 study from Washington University School of Medicine in St. Louis that found past-month marijuana use among pregnant mothers in the United States increased by 75 percent between 2002 (2.85 percent) and 2016 (4.98 percent).
As more states legalize medicinal and recreational use of cannabis, other reports suggest that many marijuana dispensaries commonly suggest cannabis as a natural cure for pregnancy related nausea.
This latest study, published March 27 in the journal JAMA Psychiatry, suggests that pregnant women should be discouraged from using cannabis at any time in their pregnancy because so little is yet known about its health effects.
But its findings also raise new concerns that prenatal exposure to cannabis may pose a greater risk after the fetal brain begins to develop a receptor system for endocannabinoids, which are part of the naturally occurring neurotransmitter network through which cannabis affects the brain.
“One possible explanation for the finding of increased psychosis risk for marijuana use following, but not before, knowledge of pregnancy is that the endocannabinoid receptor system may not be in place during the early weeks of pregnancy,” said Ryan Bogdan, associate professor of psychological & brain sciences and senior author of the paper. “Prenatal cannabis exposure may be associated with later psychosis proneness in offspring only when there is sufficient fetal endocannabinoid type 1 receptor expression, which may not occur until after many mothers learn they are pregnant.”…
…Other Washington University co-authors include Nicole Karcher, post-doctoral research scholar; Arpana Agrawal, professor of psychiatry; and Cynthia Rogers, MD, assistant professor of child psychiatry, all in the Department of Psychiatry in the School of Medicine; and Deanna Barch, chair of the Department of Psychological & Brain Sciences in Arts & Sciences and the Gregory B. Couch Professor of Psychiatry at the School of Medicine.