A genetic predisposition (sometimes also called genetic susceptibility) is an increased likelihood of developing a particular disease based on a person's genetic makeup.
The current findings, published in the journal Development and Psychopathology, follow previous research that found marriage protects against risky alcohol use and moderates genetic influences on alcohol outcomes. But previous studies generally focused on older adult samples.
"We found that marriage was not uniformly protective against alcohol misuse. In fact, we found that early marriage (i.e., by age 21) seemed to exacerbate risk for alcohol use among individuals with a higher genetic predisposition," said study author Rebecca Smith from the Virginia Commonwealth University in the US.
"Thus, early marriage does not have the same protective benefit in terms of attenuating genetic predispositions that have been observed for marriage later in adulthood," Smith added.
The study involved a sample of 937 individuals in a dataset of people who reported heavy episodic drinking and marital status between ages 21 and 25.
The findings showed that individuals who marry young tend to experience more consequences that are negative and face more challenges, such as mental health and substance use problems, than those who marry at a later age.
Individuals who marry young may not be the best influences on one another. This may create an environment in which other risk factors that contribute to alcohol use, such as genetic predispositions, are exacerbated, the study said.
"These findings are important because they demonstrate how risk and protective factors may intersect in different ways at different points across the lifespan," Smith said.
"Although marriage is typically considered to be protective, when considering the role of development a different picture emerges, such that early marriage may increase the risk of heavy episodic drinking among people who have high genetic predispositions for alcohol use. It contributes to a more nuanced understanding of the role of marriage," she added.
The researchers were somewhat surprised by their findings, given that marriage is generally considered to be protective against poor mental and physical health outcomes.