Prenatal Cannabis Exposure Tied to Mental Health Problems in Adolescence

Cannabis exposure during pregnancy was associated with an increased risk of psychopathology into adolescence, especially if exposure continued later into the pregnancy, according to longitudinal findings from the Adolescent Brain Cognitive Development (ABCD) study.

Among over 10,000 kids, prenatal cannabis exposure (PCE) was associated with “persisting vulnerability” to psychopathology throughout early adolescence compared with no prenatal exposure (P=0.004), reported David Baranger, PhD, of Washington University in St. Louis, Missouri, and colleagues.

These findings were primarily driven by cases where cannabis exposure continued even after maternal knowledge of pregnancy, possibly due to the timing of cannabinoid receptor neural expression, they noted in JAMA Pediatrics.

“Increased psychopathology may lead to greater risk for psychiatric disorders and problematic substance use as children enter peak periods of vulnerability in later adolescence,” Baranger and team wrote.

Among the psychopathologies that were significantly associated with PCE were rule-breaking behavior (P<0.001), aggressive behavior (P=0.007), social problems (P<0.001), thought problems (P<0.001), attention problems (P<0.001), and conduct problems (P<0.001).

The current findings are in line with previous findings from the ABCD study from 2020, which showed that kids exposed to cannabis in utero were at greater risk for psychopathology during middle childhood.

“During the first wave, they were just children. Now they’re edging up on adolescence,” said Baranger in a press release. “We know this is a period when a large proportion of mental health diagnoses occur.”

“Once they hit 14 or 15, we’re expecting to see further increases in mental health disorders or other psychiatric conditions — increases that will continue into the kids’ early 20s,” he added.

Of note, during the COVID-19 pandemic, cannabis use during the early stages of pregnancy increased by 25%. Previous research had also shown that women are more likely to use cannabis in pregnancy if they are depressed, anxious, or have experienced trauma.

For this study, data were collected at baseline from June 2016 to October 2018 and at two follow-up points at 1 year and 2 years for 10,631 kids.

Cannabis exposure was put into three categories: use only before maternal knowledge of pregnancy (BK-PCE), continued use after maternal knowledge of pregnancy (BAK-PCE), and no exposure (NE).

A total of 391 participants were in the BK-PCE group, 208 were in the BAK-PCE group, and 10,032 were in the NE group. Collectively, 81% self-reported as white and 22% self-reported as African American. Baseline mean age was 9.9 years, while mean age at 1-year follow-up was 10.9, and 12.0 at 2-year follow-up.

The authors used the Child Behavior Checklist subscales and the Prodromal Questionnaire-Brief Child Version to assess psychopathology.

The associations did not change with age (false discovery rate [FDR]-corrected P>0.11). Results also remained FDR-significant when including covariates with high missingness, such as pregnancy-associated covariates like maternal age at birth and planned pregnancy, except for psychotic-like experiences (FDR-corrected P=0.13). In addition, associations remained directionally consistent and of similar magnitude in the BAK-PCE group after accounting for polygenic risk in the European ancestry subsample, Baranger and colleagues said.

The small sample size of prenatal cannabis-exposed offspring was a limitation to the study, they acknowledged. Other limitations included potential underreporting of cannabis use during pregnancy; inexact data on the timing, frequency, and potency of cannabis exposure; and a lack of data on certain potential confounders, such as maternal stress during pregnancy.