July 15, 2021
Puberty and adolescence are tough times for most. But for some teens, and even pre-teens, these years are particularly grueling and even dangerous because of factors out of their control and as far back as gestation.
Kristine Marceau —never one to shy away from tough questions — often finds herself training a wide lens on influences that result in some teenagers engaging in unhealthy and risky behaviors.
She researches a combination of genetics and environment, such as maternal prenatal stress and parenting practices, to identify children who, as adolescents, might engage in risky behaviors related to early or late timing of puberty.
Marceau says understanding genetics, hormones, and early childhood environments might together lead to targeted clinical interventions.
Marceau is a recipient of a 2021 Federation of Associations in Behavioral & Brain Sciences (FABBS) Early Career Impact Award. She was nominated by the Behavior Genetics Association, and her research is funded in part by grants from the National Institute on Drug Abuse.
Among research focuses, Marceau looks at the cumulative effects of prenatal risk factors, including mothers who smoke during pregnancy and experience high levels of stress and anxiety, which often result in low-birth-weight babies.
“We aggregate many different types of prenatal experiences, like stress, substance use, and complications like infections, and categorize the different risks in terms of risk to the fetus,” Marceau says. “We look at how many insults, risk factors, are in the prenatal environment cumulatively.”
These insults, along with stresses such as a hostile family environment and genetic predispositions, all can impact puberty and stress hormones in adolescence in a way that puts kids at risk of having behavior problems and transitioning to substance use. Marceau’s work shows that genetic predispositions, prenatal experiences, and parenting can interact to predict which children are at highest risk of behavior problems.
Early puberty impacts girls more than boys, and often the child is unprepared for the changes that come along with puberty. A child entering puberty at age 10 likely still has the social and cognitive development of a 10-year-old, but may experience peers and even family members treating her as if she were older. She might be given more freedom, end up in older friend groups and engage in behaviors for which she is not developmentally prepared.
Parents, likewise, are conflicted. Interventions can help parents understand how to cope with a child who appears older than her chronological years. Since substance use also runs in families, these parents may pass on genetic predispositions or model environments that push those girls toward substance use as well.
Conversely, boys who go through puberty late may use drugs or alcohol in front of friends as if to prove they are older than they look, but this appears to be driven by their own perceptions of puberty rather than hormone changes. Boys who experience increases in testosterone earlier may be at increased risk for substance use, perhaps via mechanisms related more to brain development than social reasons.
Marceau’s research comes primarily from large-scale international and national studies, including an adoption study based in the United States and incorporating more than 561 pairs of birth and adoptive parents, and their adopted children, now between ages 11 and 15.
Data for the studies are derived from a combination of saliva, hair samples, and medical record reports, as well as family observations and parental and adolescent questionnaires.
Marceau describes her work as “a lifelong goal; it’s a constant work in progress.”
