In Utero Cocaine Exposure Disrupts Brain Development

Animal studies have shown that exposure to cocaine during prenatal development causes many disruptions in normal brain development and negatively affects behavior for the lifetime of an individual.

Similar research in humans, for ethical reasons, has been more restrained; however, research has revealed that children exposed prenatally to cocaine have impairments in attention, control, stress, emotion regulation, and memory. Past studies also suggest that such children may be more predisposed to begin substance use.

Because adolescence is the typical time of life when substance use starts, researchers from the Yale University School of Medicine (New Haven, CT, USA), led by Dr. Rajita Sinha, conducted a study to evaluate the gray matter differences and probability of substance use in adolescents who were cocaine-exposed prenatally in contrast to those who were not. The study’s findings were published October 1, 2013, in the journal Biological Psychiatry.

To accomplish this, the investigators recruited 42 adolescents between the ages of 14 and 17, exposed in utero, who are part of a long-term cohort that have been tracked since birth. They also studied 21 non-cocaine-exposed adolescents for control comparison. All of the participants underwent structural neuromagnetic resonance imaging (MRI) scanning with whole-brain voxel-based morphometry technology, and answered a questionnaire about their use of all sorts of illegal drugs, in addition to submitting urine samples for toxicology analyses.

What the researchers found was worrying, but exactly what they had hypothesized. The adolescents with prenatal cocaine exposure had lower gray matter volume in key brain regions involved in memory, reward, emotion, and executive function, compared with unexposed adolescents. Gray matter volume was also tied to initiation of substance use. Amazingly, each 1-mL decrease in gray matter volume increased the likelihood of initiating substance use by 69.6%–83.6%, depending upon the brain region.

“This study may have an important message for pregnant women who use cocaine. It appears that we need to take a long-term perspective on the risks associated with prenatal exposure to cocaine: people whose brains may appear structurally typical at birth may develop abnormally,” said Dr. John Krystal, editor of Biological Psychiatry. “While the significance of these structural changes is not clear, they merit further study.”

Gray matter processes data, and deficits in gray matter are documented in many other disorders, including anorexia, schizophrenia, and childhood attention-deficit/hyperactivity disorder. It is important to note that, as part of the study criteria, these participants had no significant medical or mental illness and differed only in whether their mothers had used cocaine while pregnant.

“Thus, for the first time in children we see how mothers’ in-utero cocaine use may translate to brain changes in the offspring that impact cognition, mood, and health of the affected offspring later in life,” said Dr. Sinha. “One can speculate that in the future, with additional validation, such specific brain alterations may serve as biomarkers of risk that can be targeted to prevent drug use and abuse.”

Related Links:
Yale University School of Medicine