Teenage risk-taking linked to lower baseline dopamine levels

Teenage risk-taking, such as experimentation with alcohol, cannabis, nicotine and other substances, may reflect a compensatory response to lower baseline dopamine, the brain chemical for reward activity, suggests a new University of Pittsburgh School of Medicine study, published today in Nature Communications.

The study's nuanced findings challenge previous beliefs associating higher dopamine with risk taking and could reshape how scientists think about brain development in adolescence. While additional research is needed, new evidence suggests that non-invasive measurements of brain dopamine could help inform research into which teens might benefit from additional support while navigating this critical stage of development and growth.

Our results suggest that, for some teens, risk-taking may act as a way to 'get the system going' when dopamine-related reward biology is lower at the start of adolescence. This finding is a big shift for the field because many people would assume higher dopamine activity would be linked to more substance use."

Ashley Parr, Ph.D., lead and corresponding author, research assistant professor of psychiatry at Pitt

Adolescence, a dynamic period during which a young person develops from a child into an adult, is a time when many teens begin testing boundaries and taking risks, including substance use experimentation. This exploratory behavior is well-known to many parents and is considered to be a normal part of growing up, an evolutionarily established biological process that is critical for brain development and progressing toward independence in adulthood.

Among a group of more than 800 teenagers, Parr and her team found that those who had lower levels of dopamine in the brain's reward system were more likely to try substances than those with higher dopamine. But as the teens got older and their dopamine systems matured, their substance use tended to decrease. Most teens who experiment with substances do not develop substance use disorder as adults, and the researchers found that, as a whole, the study cohort's substance use declined after the college years.

Unlike many adult-focused studies that measure brain dopamine after years of substance use, here researchers analyzed data from the National Consortium on Alcohol and Neurodevelopment in Adolescence and Young Adulthood (NCANDA-A), which captured changes in dopamine levels over time, including before, during and after patterns of substance use had been established. That approach helped the scientists understand whether dopamine-related differences may precede substance use behaviors rather than simply reflect the effects of substance exposure over time.

To better understand the biological underpinnings of risk-taking behavior, researchers analyzed more than 6,000 repeated assessments across years of self-reported drinking and drug use, impulsivity and ability to control those impulsive behaviors. Scientists also analyzed participants' brain scans, collected annually for up to nine years, using a technique that measures brain tissue iron as proxy for dopamine content. This technique was pioneered in the lab of Pitt professor of psychiatry Beatriz Luna, Ph.D., by then-postdoctoral fellow Bart Larsen, Ph.D., now at the University of Minnesota.

The adolescent participants did not all follow the same path. Some showed low or minimal substance use, while others fit a "youth peak" pattern - increasing use earlier in adolescence followed by declines in their mid-twenties. Notably, adolescents in the "youth peak" group had significantly lower dopamine levels in comparison to all other groups, including those whose substance use continued to increase over time, or those who engaged in substance use in adulthood. As participants in the "youth peak" group got older, their brain dopamine levels steadily but rapidly increased, coinciding with the drop in substance use.

"The key question isn't who experiments, but who continues, and who escalates their use into adulthood," said Parr. "By tracking teens over time, we were able to pinpoint early brain and behavioral markers that help distinguish temporary, developmentally typical experimentation from patterns that may signal greater long‑term risk."

This study did not measure social media behavior, though researchers noted that fast-paced, highly reinforcing digital environments may engage related reward processes, making this an important area for future research. Recent reports show that fewer youth are engaging in substance use behavior than in the past, and social media engagement could reflect a modern-day alternate means of reward-seeking. Parr's findings identifying distinct patterns of risk-taking across adolescence could be used in the future to understand the development of other forms of reward seeking, including social media behavior.

"Risk-taking is a normal part of being a teenager, and for most kids it's a phase that peaks and then eases," said Luna, senior author of the study. "Parents can help by steering that drive for new, rewarding experiences toward positive social outlets like team sports, so teens can chase that 'reward' in healthier places."

Pitt co-authors of this research are Daniel Petrie, Ph.D., Finnegan Calabro, Ph.D., Will Foran, Ph.D., Douglas Fitzgerald, Ph.D., and Duncan Clark, M.D., Ph.D.; Additional co‑authors are from Carnegie Mellon University, University of Minnesota, University of California San Diego, University of North Carolina Wilmington, University of Tulsa and Duke University.

This research was supported by the National Institutes of Health (grant 5RO1MH080243-07), the Developmental Alcohol Research Training Program from the National Institute on Alcohol Abuse and Alcoholism (grant T32 AA007453), the National Institute on Drug Abuse (grant K23DA057486), the Brain and Behavior Research Foundation, the Jacobs Foundation and the Staunton Farm Foundation.