Neural signatures of impulsivity and neuroticism are largely distinct in youth

New research published in Molecular Psychiatry suggests that two major personality traits associated with alcohol use—impulsivity and neuroticism—stem from largely distinct brain networks. While both traits heighten the risk for problematic drinking in adolescents, the biological pathways driving that risk appear to be different. This finding supports the concept that there are multiple neurological routes that can lead to similar risky behaviors in youth.

Impulsivity and neuroticism are well-known psychological risk factors for substance abuse, yet it remains unclear how these traits manifest in the brain’s complex wiring. Previous studies often focused on isolated brain regions rather than the broad communication patterns across the entire brain.

The research team aimed to determine whether these two personality traits share a common neural foundation or if they operate through separate mechanisms. By mapping these connections, the scientists hoped to clarify how different vulnerabilities contribute to the onset of alcohol use during the critical developmental period of adolescence.

“We are interested in understanding how risk factors in adolescence contribute to substance use problems later in life,” explained study authors Annie Cheng and Sarah Yip, a postdoctoral associate and an associate professor, respectively, at the Yale School of Medicine.

“Traits like impulsivity (acting without thinking) and neuroticism (tending to experience more negative emotions) are known to increase alcohol-use risk, but we still don’t fully understand what is happening in the brain that connects these traits to later outcomes—especially during adolescence, when risky behaviors and many mental health conditions first emerge. Our study uses brain connectivity patterns to better understand how these personality traits may relate to substance use at a biological level.”

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The study analyzed data from approximately 1,100 young adults who participated in the IMAGEN study, a large multi-center genetic-neuroimaging project in Europe. The participants were 19 years old at the time of the brain scans. During the magnetic resonance imaging (MRI) sessions, the participants performed a specific activity known as the Stop Signal Task. This task measures inhibitory control by asking participants to respond to a stimulus but withhold their response when a specific signal appears.

The researchers utilized a technique called functional connectivity analysis. This method examines how different regions of the brain communicate with one another by measuring the synchronization of their activity over time. Using a machine learning approach called connectome-based predictive modeling, the team sought to identify specific patterns of brain connectivity that could predict a participant’s levels of impulsivity and neuroticism.

Impulsivity was measured using the Substance Use Risk Profile Scale, which assesses a person’s tendency to act without foresight. Neuroticism, the tendency to experience negative emotions like anxiety or moodiness, was assessed using the NEO Five-Factor Inventory. The scientists also looked at the participants’ alcohol use behaviors using a standardized screening test.

The researchers found that the brain networks predicting impulsivity were fundamentally different from those predicting neuroticism. The neural signature for impulsivity was primarily characterized by connections involving motor and sensory areas of the brain. This suggests that the biological basis of acting without thinking is closely tied to the systems that manage physical movement and sensory processing.

In contrast, the neural signature for neuroticism was much more distributed throughout the brain. It involved a wide array of networks, including those responsible for emotion regulation, self-reflection, and executive control. Specifically, the neuroticism network included connections in the default mode network, the frontoparietal network, and subcortical regions.

A direct comparison of the two networks showed very little overlap. Only about 3 percent to 4 percent of the functional connections were shared between the impulsivity and neuroticism models. This indicates that while these traits often occur together in individuals, they arise from distinct neurobiological architectures.

“We were somewhat surprised by how little overlap there was between the brain networks associated with impulsivity and neuroticism,” Cheng and Yip told PsyPost. “These traits often co-occur and jointly predict a wide range of psychiatric conditions, so one might expect them to share more common neural architecture. Instead, we found that their underlying brain connectivity patterns were largely distinct. This raises an important question for future research: why are impulsivity and neuroticism implicated together in so many forms of psychopathology if their neural networks are largely distinct?”

The researchers also compared these personality networks to a previously identified brain network associated with alcohol-use risk. Both impulsivity and neuroticism networks showed some overlap with the alcohol-risk network, sharing about 10 percent to 20 percent of their connections. However, the specific connections that overlapped were different for each trait.

This finding provides biological evidence for the psychological concept of equifinality. Equifinality is the idea that different developmental pathways can lead to the same outcome. In this context, one teenager might be at risk for alcohol misuse due to motor-sensory disconnects related to impulsivity, while another might be at risk due to emotional regulation issues related to neuroticism.

“Even though impulsivity and neuroticism are both linked to alcohol-use risk, they appear to be supported by largely distinct brain networks,” the researchers explained. “In other words, two teens might be at risk for similar behaviors, but for different underlying neurobiological reasons. This supports the idea that there isn’t just one pathway to risky behavior—there are multiple routes that can lead to the same outcome.”

To ensure the results were robust, the scientists tested their models on an independent group of participants. They used data from the Adolescent Brain Cognitive Development (ABCD) Study, which includes children in the United States. Even though the ABCD participants were younger, aged 11 to 12, the models still showed a significant association, suggesting the findings are generalizable across different populations.

“The practical significance of our findings lies in improving our understanding of how vulnerability may develop into risky behavior over time,” Cheng and Yip said. “We show that impulsivity and neuroticism—two traits that both increase alcohol-use risk—are supported by largely distinct brain networks and relate to alcohol use risk via different brain connections.”

“This suggests that prevention and intervention efforts may need to differ depending on whether a young person’s risk is driven more by difficulty regulating behavior or difficulty managing negative emotions. In other words, our findings support a more personalized, mechanism-based approach to reducing adolescent risk, rather than assuming a one-size-fits-all approach.”

As with all research, there are limitations. The sample from the IMAGEN study primarily consisted of individuals of White European ancestry. It remains to be seen if these specific brain patterns apply equally to more diverse populations. Additionally, the study relied on self-reported questionnaires to measure personality traits, which may not always capture the full complexity of an individual’s behavior.

The brain scans were collected while participants were performing a specific task rather than while resting. It is possible that the brain networks might look different when the brain is not engaged in a structured activity. The study was also cross-sectional, meaning it looked at a single point in time, so it cannot definitively prove that the brain patterns caused the behaviors.

It is also important to note that these brain patterns represent risk factors rather than deterministic predictions. “These brain patterns do not mean a teenager is ‘wired’ for alcohol problems,” Cheng and Yip noted. “Instead, they point to systems that may contribute to vulnerability, helping guide prevention efforts toward strengthening regulatory skills, emotional coping, and supportive environments.”

“A key next step is to examine how these brain networks change over time and how they relate to future alcohol use or other mental health outcomes. As large longitudinal studies like ABCD continue to follow participants into later adolescence and adulthood, we will be able to test how these neural signatures evolve across development. Ultimately, we hope this work contributes to more targeted and developmentally informed prevention approaches.”

“One broader implication is that adolescent risk-taking behavior reflects highly complex interactions among developing brain systems, personality traits, and environmental factors,” the researchers said. “By studying these systems in large, diverse samples, we can move toward a more nuanced understanding of youth development that recognizes individual variability.”

The study, “Impulsivity and neuroticism share distinct functional connectivity signatures with alcohol-use risk in youth,” was authored by Annie Cheng, Sarah Lichenstein, Bader Chaarani, Qinghao Liang, Marzieh Babaeianjelodar, Steven J. Riley, Wenjing Luo, Corey Horien, Abigail S. Greene, Tobias Banaschewski, Arun L. W. Bokde, Sylvane Desrivières, Herta Flor, Antoine Grigis, Penny Gowland, Andreas Heinz, Rüdiger Brühl, Jean-Luc Martinot, Marie-Laure Paillère Martinot, Eric Artiges, Frauke Nees, Dimitri Papadopoulos Orfanos, Luise Poustka, Sarah Hohmann, Nathalie Holz, Christian Baeuchl, Michael N. Smolka, Nilakshi Vaidya, Henrik Walter, Robert Whelan, Gunter Schumann, R. Todd Constable, Godfrey Pearlson, Hugh Garavan, and Sarah W. Yip.