Marital stress may make people more vulnerable to depression, according to a recent study. The long-term study shows that people who experience chronic marital stress are less able to savor positive experiences, a hallmark of depression. They are also more likely to report other depressive symptoms. Married people are, in general, happier and healthier than single people, according to numerous studies. But marriage can also be one of the most significant sources of long-lasting social stress.