(PhysOrg.com) -- Drinking plays an important and sometimes unexpected role from one day to the next in young couples' romantic relationships, according to a new study by University at Buffalo and University of Missouri researchers.

The study extends past research by showing that alcohol use can have both positive and negative effects, and documents the circumstances in which these effects are more likely to occur.

Published November 29 in the Personality and Social Psychology Bulletin, these results may prove helpful in providing clues about who might be at risk from the adverse consequences of alcohol use within committed relationships.

"We really can't make the blanket statements about drinking and romantic relationships that people have come to expect," according to Ash Levitt, PhD, lead author on the report and postdoctoral fellow at UB's Research Institute on Addictions. "For instance, it turns out that drinking together rather than apart is clearly good for relationships. Individuals who drink with their partner report feeling increased intimacy and decreased relationship problems the next day, compared to individuals who drink apart from their partner or do not drink at all."

The beneficial outcomes for relationships were associated with relatively lower levels of drinking, one to three drinks, whereas harmful outcomes  decreased intimacy and increased relationship problems  were associated with heavier levels of drinking, as in four or more drinks.

The study included 69 heterosexual couples who averaged 20-21 years of age. The majority of the participants were white and over 90 percent were college students. Most were dating seriously and seven of the couples were married.

Levitt's colleague on the study was M. Lynne Cooper, PhD, of the University of Missouri.

Interestingly, heavy alcohol consumption was not always harmful to relationships, according to Levitt. "The harmful effects of heavy drinking were buffered when partners drank together vs. apart," he explained. "Also, when both partners drank either heavy or light amounts, as long as they were similar amounts compared to their partner, it was better for the relationship than when one drank heavily and the other lightly."

Finally, the associations between drinking and relationships were stronger and more numerous for women than for men, suggesting that alcohol use plays a larger role in romantic relationships for women than it does for men. Women appeared to drink with their partner in response to relationship problems, feeling disconnected from him, or when they perceived that he had behaved negatively toward them the day before. Also, only women were protected from the harmful effects of heavier drinking when they drank with their partner; men did not benefit in the same situation. Women also drank significantly more on days following negative events with their partners than men did after negative events.

"Using computerized or online daily diary methods to compile day-to-day variations in thoughts and behaviors provided us with very accurate sequences of events," according to Levitt. "This reliable record of effects for each gender, the nature of the drinking, and the processes occurring between the partners provided information about factors that may make or break relationships over time."

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