Landmark longitudinal research mapping brain development from pregnancy through adolescence
What makes us who we are? Is it our genetics, our experiences, or the complex interplay between both? For decades, scientists have sought to understand the fascinating journey of brain development, particularly during the critical years of childhood and adolescence.
Understanding how inherited traits influence brain development and cognitive function across the lifespan.
Examining how family, school, and community environments shape developmental trajectories.
| Feature | ABCD Study | HBCD Study |
|---|---|---|
| Developmental Period | Late childhood through adolescence (ages 9-10 into adulthood) | Prenatal through early childhood |
| Sample Size | Nearly 11,900 children | Over 7,000 families |
| Primary Focus | How experiences and biology interact during adolescence | How early exposures affect developing brain architecture |
| Key Research Questions | Effects of substance use, screen time, sleep, social environments | Impact of prenatal exposures, early adversity, protective factors |
| Research Sites | 21 sites across the U.S. | 27 recruitment sites across the U.S. |
The ABCD Study employs a comprehensive, multi-method approach to capture the complexity of adolescent development. Each year, participants undergo extensive assessments including:
Saliva samples for genetic and epigenetic analyses to understand biological underpinnings of development 8 .
Standardized tests measuring cognitive abilities, academic achievement, and mental health 8 .
Detailed surveys capturing family life, neighborhood quality, screen time, and social environments 9 .
Research is clarifying how early exposure to substances like alcohol, marijuana, and nicotine affects the developing brain, while also identifying factors that confer resilience 1 .
Scientists are tracking the onset and progression of mental health conditions, identifying both risk factors and potential intervention points 9 .
The study is revealing how factors like screen time, sleep quality, physical activity, and neighborhood characteristics influence brain development and cognitive function 9 .
| Research Tool | Primary Function | Application in ABCD/HBCD |
|---|---|---|
| Structural MRI | Creates detailed 3D images of brain anatomy | Measures brain volume, cortical thickness, and white matter integrity over time |
| Functional MRI (fMRI) | Tracks brain activity by measuring blood flow | Maps brain connectivity and identifies networks activated during tasks |
| Electroencephalography (EEG) | Records electrical activity in the brain | Assesses rapid neural responses to stimuli and measures brain maturation |
| Biospecimen Analysis | Examines genetic, epigenetic, and molecular markers | Identifies genetic risk factors and biological signatures of environmental exposures |
| Wearable Sensors | Continuously monitors physiology and behavior | Tracks infant heartbeat, movement, sleep patterns, and physical activity |
| Cognitive Assessments | Measures cognitive, emotional, and behavioral functioning | Evaluates executive function, memory, academic achievement, and mental health |
Continuous data collection across multiple timepoints enables longitudinal analysis of developmental trajectories
The ultimate goal of both studies extends beyond academic curiosity—these initiatives are designed to directly inform prevention science and public health interventions 1 .
By identifying critical windows of development and modifiable risk factors, this research can shape more effective, timely interventions.
Understanding how early stress exposure affects brain connectivity could lead to targeted support for children experiencing adversity.
Beginning in 2025, the HBCD Study will release curated, anonymized data annually, making this valuable resource available to researchers worldwide 4 . The ABCD Study already follows this model, with data from nearly 12,000 participants accessible to qualified scientists 6 .
Practical information for families to promote healthy development
Evidence-based guidelines for healthcare providers
Informed approaches for educators and policymakers
The ABCD and HBCD Studies represent a transformative moment in developmental science. By mapping the intricate journey of brain development from pregnancy through adolescence, these landmark initiatives are uncovering the fundamental factors that shape who we become.
More effective prevention strategies
Evidence-based policy guidance
Personalized intervention approaches
Enhanced child development support
The knowledge generated will provide families, educators, healthcare providers, and policymakers with practical information to promote the health, well-being, and success of future generations 9 .