Cannabis use rates among pregnant women have grown significantly over the last two decades, increasing the need for research into the potential health effects of prenatal cannabis exposure. Previous studies have linked cannabis exposure during fetal development to an increased risk of health issues like sleep problems, depression and low birth weight. Now, researchers from the Department of Psychology & Brain Sciences’ BRAIN Lab at Washington University in St. Louis have found that children exposed to cannabis in the womb show elevated rates of psychopathology symptoms that persist into early adolescence.
The latest study is a follow-up to a 2020 study in which the researchers analyzed data from the Adolescent Brain and Cognitive Development Study (ABCD Study), an ongoing longitudinal study of nearly 12,000 children with an average age of 10 years in 2020. Investigators in the ABCD Study regularly measure participants’ brain structure and activity using magnetic resonance imaging (MRI), collect biological samples and gather psychological, environmental and cognitive information with the aim of understanding factors that influence brain, cognitive and social-emotional development. The 2020 research, published in JAMA Psychiatry, found that children exposed to cannabis after the pregnancy was known (after about 5-6 weeks gestation) had elevated psychopathology including more psychotic-like experiences, more problems with depression and anxiety, more problems with impulsivity and attention, more social problems and greater sleep disturbance. The children in this group also had lower cognitive performance, lower indices of global brain structure during middle childhood and lower birth weight.
The latest study followed up with more than 10,500 children from the 2020 analysis and revealed that these elevated rates of psychopathology symptoms continued as the children aged into early adolescence. At ages 11 and 12, children with prenatal cannabis exposure continued to show signs of attention, social and behavior problems that put them at a greater risk for clinical psychiatric disorders and problematic substance use as they enter later adolescent years, the researchers said. The increased risk was most prevalent when children were exposed after about 5-6 weeks of fetal development, which aligns with the time of endocannabinoid type 1 receptor expression. While the age difference from 10 years to 12 years may seem small, this time period in development is important as a large proportion of mental health diagnoses occur during adolescence, noted first author David Baranger. This research was published in JAMA Pediatrics.
“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 kids’ early 20s,” Baranger said.
The study was supported by funding from the National Institutes of Health. As cannabis becomes more widely available across the country, the results further support caution against using cannabis during pregnancy, the authors said.