Men whose wives or girlfriends have had breast cancer are at a significantly higher risk than other men of developing severe depression, a 13-year study has found.

That finding and others from an institute in Denmark underscore the need to pay attention not only to cancer patients but to their caregivers, an American Cancer Society analyst told MyHealthNewsDaily.

In a study of more than a million Danish men, researchers from the Institute of Cancer Epidemiology. in Copenhagen, determined that those men whose partners had breast cancer were 39 percent more likely to be hospitalized for a mood disorder such as severe depression than were men with healthy wives or girlfriends.

Men whose partners had more more-severe breast cancer were more likely to have more-severe depression, the researchers said. And men whose partners suffered a relapse were more likely to develop a mood disorder than men whose partners stayed cancer-free.

Men whose partners died from breast cancer were 3.6 times more likely to develop a mood disorder than men whose partners survived, the study said.

Although the study focused on the partners of women with breast cancer, the risks for severe depression can be applied to anyone helping to care for a cancer patient, the researchers said.

The study, which was published online today (Sept. 27) in the journal Cancer, shows that the struggles that cancer patients undergo affect the people who support them, said American Cancer Society research analyst Rachel Cannady, who did not work on the study.

"When a person is diagnosed with cancer, it's not just the person who is diagnosed, it affects the entire family," Cannady said. "Anyone in the family may experience higher levels of distress and they probably have a shift in roles."

The findings were in line with those of previous studies, she added.

Cancer organizations and hospitals have to do a better job of providing programs for caregivers, Cannady said, because the vast majority of current programs are targeted to patients.

"In order for the cancer patient to have a better quality of life, their family caregiver has to have a better quality of life," she said.

It's important for the partners of all cancer patients to be conscious of their own mental well-being during the treatment process, she said. If a partner is getting overwhelmed, he or she can talk to family members or friends to alleviate stress, and it may decrease the chance of developing anxiety and depression.

It's also important for caregivers to take care of themselves by eating right and exercising regularly, Cannady said.

They'll be "less prone to experience depression, because they know how to make themselves feel better," she said. "It's kind of their own social support."