JOIN USPeople who are married, or cohabiting, tend to drink less than their single, widowed and divorced counterparts, a new study has claimed.
"Intimate relationships cause a decline in alcohol consumption," said Diana Dinescu from University of Virginia (UVA) in the US.
Dinescu and colleagues compared the reported drinking patterns of twins in and out of relationships.
Previous studies have shown that married adults drink less than single or divorced people.
Researchers examined the behaviours of 2,425 same-sex twin pairs to see if these findings held up among people who share genetic and familial backgrounds.
Previous studies used more random sample pools that might include unidentifiable variables that could skew results.
"It is impossible to tell from correlational research whether marital status has a protective effect, or whether people who naturally drink less simply are more likely to get married," said Dinescu.
"By using twins, our study allows us to eliminate entire classes of alternative explanations, such as genetic predispositions and upbringing influences, and brings us a step closer to understanding the true impact of relationships on drinking behaviour," she said.
Researchers culled their data from the Washington State Twin Registry, a database of twins who participate in health and behaviour research.
Their sample included 1,618 female pairs and 807 male pairs. Registry participants stated on forms whether they were married, divorced, widowed, separated, never married or living with a partner.
They also included information about their level of alcohol consumption - how much they drank when drinking, and how frequently they drank.
Researchers compared married twins with their single, divorced and cohabiting co-twins on drinking frequency and quantity.
The married co-twins, they found, consumed less alcohol than their single or divorced co-twins and also drank less frequently. Cohabiting twins, like their married cohorts, consumed less alcohol than single or divorced twins.
Researchers found that cohabiting participants generally drank more frequently than married men and women participants, but less than their single, widowed and divorced counterparts.
The study concluded that once a relationship is over, people may be more inclined to drink more heavily in a session, but not necessarily more frequently.
"It seems that intimate relationships may provide a real benefit in terms of drinking behaviour, maybe through mechanisms such as a monitoring effect that partners have on each other," said Dinescu.
The findings were published in the Journal of Family Psychology.