Summary: New research finds that the habits, personality traits and mental health of romantic partners can change how strongly genetic risk affects an individual’s tendency to binge drink. Using data from Finnish twins and their long-term partners, the study shows partners who smoke, experience psychological distress or score low on conscientiousness increase the expression of genetic risk for binge drinking. Unexpectedly, heavier partner alcohol use appeared to reduce genetic influence, suggesting environmental factors can outweigh biological predisposition.
These results point to new directions for couple-focused prevention and treatment, indicating that addressing partner behaviors and personal characteristics alongside relationship dynamics could improve interventions for unhealthy alcohol use.
Key Facts:
- Partner characteristics matter: A partner’s smoking, higher psychological distress and lower conscientiousness amplify genetic susceptibility to binge drinking.
- Surprising interaction: More frequent alcohol use by a partner was linked to a smaller role for genetic risk, shifting influence toward environmental factors.
- Clinical relevance: Findings support broadening couple-based interventions to include partners’ substance use and mental health, not only relationship processes.
Source: Virginia Commonwealth University
Overview of the study
Researchers from Virginia Commonwealth University and Rutgers University analyzed data to better understand how romantic partners shape the expression of genetic risk for alcohol misuse. The team examined whether specific partner traits modify the genetic contribution to alcohol consumption and binge drinking.
Mallory Stephenson, Ph.D., a postdoctoral fellow at the Virginia Institute for Psychiatric and Behavioral Genetics at VCU, co-led the study with Jessica E. Salvatore, Ph.D., now an associate professor of psychiatry at Rutgers Robert Wood Johnson Medical School. Their findings were published May 5 in Clinical Psychological Science.
Genetic factors explain roughly half of an individual’s risk for alcohol use disorder and risky drinking, but the role of genetics varies depending on environmental exposure. The researchers note that stressful life events can amplify how genes influence behavior, while supportive or low-stress environments may reduce genetic effects.
Previous work led by VCU showed that being in a romantic relationship often associates with reduced risky drinking among people with genetic predisposition. This study drills down to ask whether particular partner characteristics—such as substance use, personality or psychological distress—moderate genetic influences on drinking.
The team used anonymized data from FinnTwin16, a long-term registry-based study of twins in Finland. They focused on twins in their 30s who were in long-term relationships and had initiated alcohol use. The analytic sample included 1,620 twins and their romantic partners, with survey information on alcohol and cigarette use, personality traits and mental health.
Twin designs enable researchers to separate genetic and environmental contributions by comparing identical twins (who share all their genes) and fraternal twins (who share about half). This allowed the authors to model gene–environment interaction: whether partner traits change the magnitude of genetic influence on drinking behavior.
Key results included expected social-concordance patterns: people were more likely to drink and binge when their partners drank or smoked frequently. In identical twin comparisons, partners’ influence on drinking appeared stronger for male twins than for female twins.
Beyond these social effects, the team found evidence that partners modify genetic contributions to binge drinking. Genetic influence on binge drinking increased when partners smoked more often, were lower in conscientiousness, higher in extraversion or neuroticism, or reported greater psychological distress. Conversely, genetic influence on binge drinking decreased when partners themselves drank alcohol more frequently—an unexpected finding the authors interpret as a shift in explanatory weight from genes to shared environment in those contexts.
The investigators emphasize that partner characteristics can reshape the balance between genetic and environmental factors. As Stephenson put it, if one influence accounts for a smaller portion of risk, other influences necessarily account for a larger portion.
Clinical implications include potential refinement of couples therapy and couple-based prevention, extending focus beyond relationship dynamics to include partner substance use, personality and mental health. The research team also notes the need for further studies to examine how relationship quality, parenting responsibilities and other contextual factors intersect with partner traits to shape drinking trajectories.
Funding: The study received support from the National Institute on Alcohol Abuse and Alcoholism (part of the National Institutes of Health) and the Academy of Finland.
About this genetics and AUD research news
Author: Olivia Trani
Source: Virginia Commonwealth University
Contact: Olivia Trani – Virginia Commonwealth University
Image: The image is credited to Neuroscience News
Original Research: Closed access.
“Associations of Romantic Partners’ Characteristics With Alcohol Consumption and Binge Drinking: Examining Evidence for Gene–Environment Interaction” by Mallory Stephenson et al. Clinical Psychological Science
Abstract
Associations of Romantic Partners’ Characteristics With Alcohol Consumption and Binge Drinking: Examining Evidence for Gene–Environment Interaction
This study evaluated how romantic partners’ alcohol use, cigarette smoking, personality traits and psychological distress relate to alcohol consumption and binge drinking in a Finnish twin sample (N = 1,620; 51% female; mean age = 33.6) and their partners. Using twin modeling, the authors tested whether partner characteristics moderate genetic influences on drinking. Partner alcohol use and smoking were consistently associated with greater alcohol consumption and binge drinking and also moderated genetic influences on alcohol use. Additionally, heritability of binge drinking was higher when partners reported less frequent alcohol use, greater smoking, lower conscientiousness, and higher extraversion, neuroticism and psychological distress. These results underscore the complex role romantic partners play in shaping drinking behavior and gene–environment interplay.