Alcohol has been proven to harm relationships; when one partner drinks heavily and the other does not then they are more likely to separate than partners that drink a similar amount or not at all. Researchers from the Oregon Health and Science University wanted to learn more about why these long-term relationships break down. For example, they were interested in whether heavy drinking causes the problems, or if the partner turns to drinking as a result of an unhappy relationship.

So, obviously, they turned to prairie voles (Microtus ochrogaster) to test their theories. Prairie voles are eerily similar to humans in the effect of alcohol on relationships. Actually, it turns out that prairie voles are similar to humans in at least two aspects: they have monogamous relationship and enjoy booze.

“Not many rodents form long-term social attachments and not many rodents like to drink alcohol. However, prairie voles are unusual as they are socially monogamous and like drinking alcohol, so they are perfect to investigate the role of alcohol in relationships,” says Andrey Ryabinin, of Oregon Health & Science University.

The reason that researchers turned to an animal is that they wanted to directly investigate how alcohol affects the brain and relationships. They hope to apply this information to human relationships to help them overcome the negative consequences of alcohol.

First, the male and female prairie voles were allowed to form a social bond over a week. Then the males were given access to a 10% alcohol solution and the female partner was either given water or alcohol. A control had both sexes drinking just water. Next, the males had a choice between spending time with his partner or a new female. The researchers watched carefully and timed how long the vole spent next to his partner and the new female. The strength of the bond between the partners was then calculated.

Sure enough, the drunkard prairie vole males spent less time with their original partner. The voles that drank no alcohol or a similar amount to their partners spent more time next to them. Uneven drinking affected these prairie voles’ relationships and even their brains. The male prairie voles that drank alcohol showed changes in their periaqueductal grey brain region.

“Our results in prairie voles have identified a biological mechanism that could explain the link between discordant drinking and relationship breakdown, but we will need to do further work to confirm this for humans,” says Ryabinin. “In future studies, we might be able to find strategies to overcome the negative effects of alcohol, to improve relationships that are disrupted by problematic drinking.”

It seems, from this study, that drinking causes the relationship to deteriorate, as a decrease in bond was observed after uneven alcohol consumption. It also appears to be due to a change in the male, though perhaps it is indirectly affected by the behavior of the female. Further studies will be needed to fully explain the role of alcohol in relationships.

Journal reference: Andre T. Walcott, Andrey E. Ryabinin. Alcohol’s Effects on Pair-Bond Maintenance in Male Prairie Voles. Frontiers in Psychiatry, 2017; 8 DOI: 10.3389/fpsyt.2017.00226.

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