Prenatal Cannabis Exposure May Increase Risk of Mental Illness in Offspring, Study Suggests

Children of women who used cannabis while they knew they were pregnant may be at greater risk of symptoms of mental illness than children of women who did not use cannabis during pregnancy, according to a report in JAMA Psychiatry. For instance, youth who were exposed to cannabis in the womb were more likely to report more psychotic-like experiences, as well as problems with aggressive behavior, depression, and anxiety than those without such exposure.

“[P]regnant women, and even those contemplating pregnancy, should be discouraged from using any cannabis by health care professionals, dispensaries, and others,” wrote Ryan Bogdan, Ph.D., of Washington University in St. Louis and colleagues.

Bogdan and colleagues analyzed data from 11,489 children enrolled in the Adolescent Brain and Cognitive Development (ABCD) study—an ongoing study tracking the brain development of U.S. children through adolescence. Based on retrospective prenatal cannabis use reported by parents or caregivers of children in the study, the researchers divided the ABCD study participants into three groups: no exposure to cannabis (n=10,834), exposure to cannabis prior to maternal knowledge of pregnancy only (n=413), and exposure to cannabis after maternal knowledge of pregnancy (n=242). The average age of children in the study was 10.

The researchers used several validated questionnaires to measure outcomes in children including the Prodromal Questionnaire–Brief Child to assess child-reported psychotic-like experiences and the Child Behavior Checklist to assess internalizing problems (for instance, depression and anxiety) and externalizing problems (for instance, aggressive behavior) as well as attention, thought, sleep, and social problems.

The researchers found that children whose mothers had used cannabis before or after they learned they were pregnant were more likely to have psychotic-like experiences and increased internalizing and externalizing problems compared with children who had no prenatal exposure. Exposure later in pregnancy, after mothers had learned of their pregnancy, was related to greater psychiatric problems in children even after adjusting for possible variables such as family demographics.

“It is clear that more studies on the association between prenatal cannabis exposure and offspring developmental outcomes are needed to examine potential causal effects, moderating or protective factors, and biological mechanisms,” the researchers wrote. “Similar to the effective messaging surrounding the adverse consequences of alcohol and tobacco exposure during pregnancy, education regarding the potential harms associated with prenatal cannabis use is necessary.”

For related information, see the Psychiatric News article “Cannabis Use During Pregnancy on the Rise.”

(Image: iStock/Nastco)

Individuals With Aggression-Related Diagnoses Are More Likely to Have Had Mild Head Injuries

Clinicians evaluating individuals with intermittent explosive disorder or self-directed aggression should be sure to ask them about a history of head injury, concluded a study published earlier this month in the Journal of Neuropsychiatry and Clinical Neurosciences.

Individuals with intermittent explosive disorder, as well as people with a history of suicidal or self-injurious behavior, were found to be twice as likely to have a history of mild traumatic brain injury (mTBI) than those with other psychiatric disorders or healthy controls, according data from a study by Emil F. Coccaro, M.D., of the University of Chicago and Caterina Mosti, Ph.D., of Drexel University.

Mild TBI is highly prevalent, with more than 1.3 million injuries occurring in the United States each year. Additionally, some 15% of returning military service personnel are estimated to have sustained an mTBI. Since many people who experience mild head injury do not seek medical treatment, this is likely a significant underestimation, the authors wrote. While the resulting cognitive, physical, and emotional consequences typically resolve within three months of the injury, a growing body of research suggests that 10% to 31% of those with mTBI injuries suffer lingering physical symptoms and mood disturbances.

To explore the relationship between history of mTBI and aggression, the researchers interviewed 1,634 physically healthy adults (this group included 695 participants with intermittent explosive disorder, 486 participants with a current/lifetime diagnosis of a psychiatric disorder that was not intermittent explosive disorder, and 453 with no psychiatric disorder). During these interviews, study participants were asked to report any history of mTBI (defined as a blow to the head associated with mild neurological symptoms including any of the following: dizziness, disorientation, memory difficulties lasting less than 24 hours, or loss of consciousness of less than 30 minutes). The participants were also asked questions about aggressive and impulsive behaviors.

Among patients who had a mTBI, 11% had no evidence of psychiatric disorder, 12% had a psychiatric or personality disorder (other than bipolar or schizophrenia/psychotic disorders), and 24% had intermittent explosive disorder. About 25% of those with mTBI had suicidal and/or self-injurious behavior. Participants reporting two or more loss of consciousness episodes had the highest aggression scores of all groups.

“On the basis of these data alone, we cannot say whether the presence of high trait impulsivity and aggression led IED [intermittent explosive disorder] participants to be in circumstances that increase risk for mTBI or whether history of mTBI altered the brains of mTBI participants, leading to an increase in aggressive and impulsive behavior post-mTBI,” the authors wrote. “That said, impulsive-aggressive behaviors are present from very early life, and individuals with this temperament are likely to place themselves in circumstances associated with bodily injury, including mTBI.”

For related information on aggression following TBI, see the Psychiatric News article “Amantadine May Reduce Aggression in TBI Patients.”

(Image: Olimpik/Shutterstock)

Follow Psychiatric News on Twitter!