How genetic risks impact the manifestation of alcohol use disorder

Multiple types of genetic influences impact the severity and presentation of alcohol use disorder (AUD), according to what may be the first study examining the joint effects of three types of genetic liability on alcohol outcomes.

About half the risk for AUD is known to be genetically inherited. Some genetic influences manifest as struggles with self-regulation, such as childhood conduct problems and risk-taking (“externalizing” behaviors). Other genetic vulnerabilities show up as tendencies toward depression and negative affect (“internalizing” behaviors), while a third group of genetic influences is alcohol-specific (e.g., affecting how alcohol is metabolized).

Large studies mapping relevant genetic variants are enabling polygenic scoring (PGS) that captures individuals’ overall genetic susceptibility to AUD. The study in Alcohol: Clinical & Experimental Research explored how genetic factors underlying externalizing, internalizing, and alcohol-specific effects jointly shape AUD and co-occurring behavioral issues and personality traits.

The authors worked with data from 6,883 adults of European-like ancestry. The participants were assessed for AUD, childhood conduct problems and adult antisocial behavior, major depressive disorder, and additional traits and tendencies. The participants were grouped according to whether they were high or low on each of the three genetic liabilities, with 2,006 people falling into groups with different patterns of genetic risk that were compared.

Nearly 6 in 10 participants in the high-risk sample met criteria for AUD, with varying severity. Broadly, those with high PGS across multiple genetic risk dimensions met more AUD diagnostic criteria than people with high PGS in fewer categories or with lower PGS.

Participants with only one high-risk score had similar AUD outcomes regardless of risk type, suggesting that risk type matters more as genetic vulnerabilities multiply. That said, externalizing genetic liability was linked to greater overall risk than internalizing genetic liability. The effects on AUD outcomes were largest for high PGS in all three categories, and for the high externalizing plus high alcohol-specific genetic risk group.

Although depression genetic liability in itself was linked to worsening AUD outcomes, in combination with additional high genetic risk scores it did not confer additional vulnerability. Among individuals with AUD, the type of genetic risk individuals carried impacted their pattern of co-occurring disorders and traits. Individuals with AUD who carried high externalizing PGS had more childhood conduct problems and antisocial personality disorder, and individuals with AUD with high internalizing PGS had more depression and neuroticism. This information indicates that genetic risk influences both the severity and likelihood of developing AUD, as well as patterns of comorbid conditions.

The findings help elucidate the complex relationships between genetically influenced risk pathways for AUD. They highlight the dominant role of externalizing genetic risk factors, especially when other PGS are high. Internalizing genetic risk was less predictive of AUD. The analysis suggests PGS could anticipate AUD risk relatively early in life and that the type(s) of genetic risk may shape clinical presentation and co-occurring issues.

By the Research Society on Alcohol for Newswise. The Gayly online. 10/26/26 @ 12:30 p.m. CST.