Prenatal Marijuana Use Not Linked to Increased Risk of Childhood Anxiety or Depression, Study Finds
- Marijuana use during early pregnancy was not linked to an increased risk of children developing anxiety or depressive disorders by age 13, based on a large study analyzing health records of over 115,000 children and their mothers.
- The study found a 16% lower recorded risk of anxiety diagnoses in children exposed to marijuana early in pregnancy, but researchers cautioned this should not be interpreted as marijuana being protective due to potential confounding factors.
- After adjusting for demographic and health variables, prenatal marijuana exposure showed no significant association with childhood depression, and no clear dose-response relationship was found with anxiety diagnoses.
- The study noted limitations including marijuana exposure being measured only during early pregnancy, lack of data on product strength and consumption methods, and emphasized that findings do not imply marijuana use during pregnancy is safe, as it remains linked to other adverse outcomes.
Marijuana use during early pregnancy was not associated with an increased risk of children developing anxiety or depressive disorders by age 13, according to a large new study (PDF).
The study was conducted by researchers from Kaiser Permanente Northern California, the University of California, San Francisco, Oregon Health and Science University and other institutions.
Researchers examined health records for 115,533 children born between 2011 and 2017 to 97,376 pregnant individuals receiving care through Kaiser Permanente Northern California.
Participants were screened for marijuana use at approximately eight to 10 weeks of pregnancy through both self-reported questionnaires and urine tests for tetrahydrocannabinol (THC). Overall, 4.4% screened positive for marijuana use.
The children were followed from age 6 through as late as age 13. During the follow-up period, 9,230 children were diagnosed with an anxiety disorder, while 1,224 were diagnosed with a depressive disorder.
In the fully adjusted analysis, prenatal marijuana exposure was not associated with an increased risk of either condition. Children exposed during early pregnancy had a 16% lower recorded risk of an anxiety diagnosis, with an adjusted hazard ratio of 0.84, but the researchers cautioned against interpreting the finding as evidence that marijuana provides protection.
The inverse association was limited primarily to cases identified through positive THC tests when the pregnant individual did not report using marijuana. Self-reported use was not associated with a reduced anxiety risk, and there was no clear relationship between frequency of use and anxiety diagnoses.
Researchers said the lower recorded risk could reflect unmeasured differences between families, differences in recognizing childhood anxiety symptoms or a reduced likelihood of seeking medical care.
Prenatal marijuana use initially appeared to be associated with a higher rate of childhood depression before researchers accounted for demographic factors, other substance use and maternal physical and mental health conditions. After those adjustments, the association was no longer statistically significant.
“In a large, diverse cohort of pregnant individuals and their children, maternal cannabis use during early pregnancy was not associated with an increased risk” of childhood anxiety or depression, the researchers concluded.
The authors noted several limitations. Marijuana exposure was measured only during early pregnancy, preventing researchers from determining whether use continued later in pregnancy. The study also lacked information about product strength, consumption method, paternal use and secondhand exposure.
The findings apply only to anxiety and depressive disorders diagnosed during childhood and do not establish that marijuana use during pregnancy is safe. The researchers noted that prenatal marijuana use has been associated with other adverse maternal and neonatal outcomes, and national guidelines continue to recommend avoiding marijuana during pregnancy.