Gregory G. Homish, assistant professor of health behavior, and colleagues at the University at Buffalo's School of Public Health and Health Professions tracked 634 couples recruited from 1996 to 1999 when they applied for marriage licenses. The majority were European-American, approximately one-third were African-American and a small percentage were Hispanic, Asian and Native American.
"Most studies that investigate the impact of substance use focus solely on individual-level risk factors, and do not consider the impact of social network influences such as those that exist from a partner," Homish said in a statement.
The results, published in the journal Addiction, showed that when a couple's drinking habits were similar, both partners remained relatively satisfied with their marriage. The same results were found for smoking.
However, if one spouse drank heavily or smoked while the other did not that dissatisfaction set in and relationships deteriorated.