Cannabis use during pregnancy may leave molecular "fingerprints" in the placenta that are linked to a higher risk of schizophrenia and other mental health problems in children, new research suggests.
Large human studies have shown that when babies are born with low birth weight, certain genetic markers in the placenta are altered, and these markers are strongly tied to a higher chance of schizophrenia, autism, and cognitive problems later in life.
Schizophrenia is a severe mental illness marked by psychosis, where people struggle to tell what is real, and it affects about 1% of the population in countries such as Canada, according to Science Alert.
Researchers say the placenta may act like a "recording device" for conditions in the womb, capturing both healthy and harmful influences that shape brain development before and after birth.
The latest work focused on tetrahydrocannabinol (THC), the main psychoactive ingredient in cannabis, and how it affects the placenta during pregnancy. In a rat model, scientists fed pregnant animals edible THC and later tested their offspring using a measure called prepulse inhibition, which checks how well the brain filters out unnecessary information and is commonly used in schizophrenia research.
Both male and female offspring exposed to THC showed reduced prepulse inhibition, a pattern that is considered an early marker of schizophrenia-related brain changes.
When the team examined the placentas from these THC-exposed pregnancies, they found increased levels of several genes that match human placental markers previously linked to schizophrenia risk.
To see if this could also occur in humans, they exposed isolated human placental cells to THC for 24 hours and observed similar increases in schizophrenia-related genes. The findings suggest that cannabis exposure may alter the placenta in a way that mirrors known genetic risk pathways for schizophrenia, Yahoo News reported.
Experts stress that these results do not prove cannabis directly causes schizophrenia, but they add to growing evidence that prenatal cannabis exposure is associated with small but meaningful increases in psychosis-related traits in children and adolescents.
Earlier epidemiological work has linked cannabis use during pregnancy, especially after the mother knows she is pregnant, to higher psychosis proneness and other mental health symptoms in offspring, even after accounting for many other risk factors.
The new placental findings could eventually help doctors identify at-risk children much earlier, possibly starting at birth by analyzing the placenta after delivery. Researchers say that, for now, the safest advice remains to avoid cannabis during pregnancy and call for more studies to confirm which cannabis components and doses are most harmful to fetal brain and placental development, as per The Conversation.
Originally published on Medical Daily
