Expecting mothers who use cannabis during pregnancy may cause paranoia and schizophrenia in their children when they get older. File Photo by 7raysmarketing/pixabay

March 27 (UPI) -- Expecting mothers who smoke marijuana or use the drug in any form may be putting their children at risk for psychosis later in life, a new study says.

Women who use cannabis during pregnancy may cause paranoia and schizophrenia in their children when they get older, according to new research published Tuesday in JAMA Psychiatry.


"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, a researcher at Washington University in St. Louis and study lead author, in a news release.

Tetrahydrocannabinol, or THC, the main psychoactive part of marijuana, can penetrate the placental barrier to interfere with the developing fetus.

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Marijuana use by pregnant women shot up by 75 percent between 2002 and 2016. Some marijuana dispensaries even suggest pregnant women use the drug to curb the effects of pregnancy-related nausea, one study shows.

"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, a researcher at Washington University and study senior author, in a news release. "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."

In 2017, the American College of Obstetricians and Gynecologists also recommended that pregnant mothers discontinue the use of marijuana.

Over the years, growing research has added to worries that cannabis can cause both mental and physical harm to users.

One study says people who smoke high-potency cannabis daily run the risk of being diagnosed with paranoia, schizophrenia and other psychosis disorders. Other findings show that Colorado, the state at the forefront of the pot legalization movement, has seen 33 times more visits to the emergency room from people who ate edible marijuana.

The drug has even been linked to depression and suicidal behavior in young people.

"Given increasing cannabis accessibility and potency, as well as growing public perceptions that it's safe to use, it is critical for additional research to understand the potential adverse consequences and benefits of cannabis throughout development and how these associations may arise." Bogdan said. "In the meantime, evidence that prenatal marijuana use is associated with a small increase in offspring psychosis proneness suggests that marijuana use during pregnancy should be discouraged until more is known."