Prenatal cannabis use may heighten ADHD and cannabis dependency risks in children
Amid a rising prevalence of cannabis use among pregnant women, an Israeli study sheds new light on the potential neuropsychiatric risks in children exposed to the drug in utero.
Cannabis
Pregnant women are more frequently turning to cannabis to alleviate the nausea and vomiting associated with morning sickness, stimulate appetite, manage pains and aches or relieve stress and anxiety. Some women who used cannabis regularly before becoming pregnant — particularly for chronic conditions — might continue its use out of habit, dependency, or because they are unsure about the risks.
A team of researchers from Hebrew University and the Hadassah Medical Center in Israel found a slight increase in the risk of attention-deficit/hyperactivity disorder (ADHD) and a heightened vulnerability to cannabis use in children whose mothers used marijuana during pregnancy. However, the researchers did not find significant associations with other neuropsychiatric conditions, such as autism spectrum disorder (ASD), psychosis, anxiety, or depression.
The research — led by Professor Ilan Matok and Dr. Hely Bassalov of Hebrew University in collaboration with Hadassah’s Professor Omer Bonne and Dr. Noa Yakirevich-Amir — was recently published in the peer-reviewed American Journal of Obstetrics and Gynecology.
The study is a systematic review and meta-analysis involving over 500,000 participants from various observational studies. It focused on assessing the potential risks of prenatal exposure to Δ9-tetrahydrocannabinol (THC), the primary psychoactive compound in cannabis. THC is known to cross the placenta, potentially influencing the developing brain of the fetus.
The study notably found no significant association between prenatal cannabis exposure and an increased risk of several major neuropsychiatric disorders, including ASD, psychotic symptoms, anxiety, or depression. However, it did identify a slight increase in the risk of ADHD and a higher likelihood of cannabis use among the offspring of women who used cannabis while pregnant.
“These findings suggest that while prenatal cannabis exposure does not appear to significantly increase the risk for many neuropsychiatric disorders, there is still a mild increase in the risk for ADHD and a greater likelihood of cannabis use in the offspring,” said Matok.
One of the critical aspects of this study is its emphasis on the changing potency of cannabis over time. The studies analyzed were conducted between the 1980s and early 2000s, a period when cannabis typically contained lower levels of THC compared to today’s strains. As a result, the study’s findings may underestimate the potential impact of contemporary prenatal cannabis exposure on long-term neuropsychiatric outcomes.
Matok insisted that findings need to be interpreted cautiously, stressing that the researchers did not confirm the safety of cannabis consumption during pregnancy.
“While our study provides important insights, it is crucial to recognize that these results are not definitive,” Matok said. “Pregnant women should be aware of the potential risks, and healthcare providers should continue to advise caution when it comes to cannabis use during pregnancy.”
Some studies have also linked prenatal cannabis use with low birth weight, preterm birth, and small head circumference, although findings are not entirely consistent. Evidence also suggests that in utero exposure to cannabis might contribute to delays in cognitive and motor development in early childhood.
