Your spouse may drive you crazy at times, but research suggests that your marriage may keep you from losing your mind.

The risk of dementia was significantly lower for married people than for adults who remained single their entire lives, according to a report in November in the Journal of Neurology, Neurosurgery &Psychiatry.

Husbands and wives also fared better than widowers and widows, researchers found.

The analysis included more than 800,000 people who participated in 15 previously published studies.

Most of the study volunteers hailed from Sweden, with the rest living elsewhere in Europe, the United States, Asia or Brazil. Nearly 30,000 of them had some form of dementia.

The authors of the report said they had several reasons to suspect that marriage might keep the brain in good working order.

People who are married spend more time in the company of another person, and social engagement is associated with a reduced risk of dementia. Perhaps years of interacting with a husband or wife builds up a “cognitive reserve” that makes the brain more resilient to future damage, the researchers wrote.

Married people also tend to be healthier, perhaps because their spouses nag them to eat their vegetables, quit smoking and take their blood pressure medications. Better physical health could translate into better brain health by reducing the risk of things like heart disease or a stroke, the researchers surmised.

It seems that they were on to something.

Nine of the studies they examined compared dementia risk in married people and those whose spouses had died. In these studies, the risk of dementia was 2 percent to 41 percent higher for widows and widowers than for people whose spouses were still alive. Overall, the added risk associated with being widowed was 20 percent.

In addition, six of the studies compared the dementia risk in people who were married and in people who were lifelong singles. The singles consistently faced a higher risk, ranging from 7 percent to 90 percent. Overall, the added risk for those who had never married was 42 percent.

To put those figures into perspective, the researchers noted that people who are sedentary are about 40 percent more likely to develop dementia than people who are physically active. Smokers and those with high blood pressure are about 60 percent more likely to develop dementia than people who don’t have either of these problems.

Finally, seven of the studies compared dementia risk in those who were married and those who were divorced. There was no difference between the two groups.

The researchers suspect that widowhood is worse than divorce because bereavement causes stress that makes it easier for dementia to take hold. Studies have found that being widowed is more stressful than getting divorced, they noted.

None of this means that people should get married simply to ward off dementia. But understanding why marriage is associated with better cognitive health could lead to the development of “social interventions” that would be available to everyone, the authors concluded.

That won’t be easy, according to an editorial that accompanied the study.

“The challenge remains on how these observations can be translated into effective means of preventing dementia,” the editorial warns. “Although potentially modifiable risk factors for dementia exist, that does not mean that dementia is easily preventable.”