Current Studies
What we’re working on now
From a new statewide twin cohort to national longitudinal datasets, our active projects trace how environment and behavior shape the brain across development.
Enrolling Studies
The Vanderbilt University Twin Research Center (VUTRC)
Our lab is currently in the process of assembling a representative cohort of adolescent and young-adult twins in the state of Tennessee. These participants will power our lab’s original data-collection efforts, including projects that combine twin methods with high-frequency data collection to better understand causal relationships between people’s lived experiences, psychosocial stress, mental health, and substance use.
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Ongoing research
Using longitudinal twin studies to test whether substance use harms the brain and mental health
We ask whether using substances such as alcohol, cannabis, and nicotine in adolescence actually harms the brain and mental health, or whether those links instead reflect the genes and environments that shape both. Comparing twins who differ in their use holds constant the genes and upbringing they share, helping separate a substance’s effects from the traits that lead people to use it — for example, much of the apparent link between adolescent cannabis use and later mental-health and cognitive problems fades within twin pairs, while the link to lower educational attainment persists. We are extending this work in a new statewide twin cohort built for intensive, repeated assessment.
Testing how childhood adversity and victimization shape mental health — and what protects against them
We study how stressful and adverse experiences in childhood — being victimized, mistreated, or exposed to other hardships — shape later mental health, and what helps some children weather them. Following large cohorts from childhood into adulthood, we model how exposure and symptoms unfold together over time to ask which comes first and whether the link holds within families. Greater victimization, for example, is followed by broad increases in mental-health problems rather than any single disorder.
Tracing how childhood adversity and mental health shape adult education and economic outcomes
Childhood adversities and mental-health conditions predict how people fare decades later — how far they go in school, the work they find, and what they earn. To ask whether these early conditions actually shape those outcomes, we lean on natural experiments and quasi-experimental designs that use differences chance creates between otherwise similar people. Childhood ADHD, for example, predicts lower educational attainment even between twins raised in the same home, pointing to academic engagement as one pathway that might be changed.
Tracking how childhood disadvantage shapes later substance use
We ask whether children who grow up with fewer economic resources go on to use substances more heavily, and through what pathways. Following national cohorts from childhood into adulthood, we model how disadvantage and the use of alcohol, cannabis, and nicotine unfold together, and test whether differences in brain development and self-regulation help explain the link. Comparing siblings raised together helps separate disadvantage from what families share. One focus is the alcohol harm paradox: why more disadvantaged drinkers often suffer greater alcohol-related harm even at similar levels of drinking.
Studying the minority who reach midlife without ever developing a mental disorder
Across a lifetime, most people meet criteria for a mental disorder at some point, so lasting freedom from one is uncommon — in one birth-cohort study followed into midlife, only about 1 in 6 reached their late thirties never having been diagnosed. We study this minority, much as researchers study people who stay healthy into very old age, to learn what sets them apart and how mental health is maintained. So far, temperament and self-control seem to matter more than wealth, physical health, or intelligence.