Being primary caregiver to a spouse who has dementia does substantially increase the caregiver's risk of cognitive decline due to caregiver burnout. [1]
I'm not sure if this is what you were trying to express.
[0] https://jnnp.bmj.com/content/89/3/231
[1] https://www.ovid.com/jnls/neurotodayonline/fulltext/10.1097/...
18 year study found unmarried more likely to not have dementia:
https://alz-journals.onlinelibrary.wiley.com/doi/10.1002/alz...
So either way, like how if ya live long enough some kind of cancer would get ya, so will mental illness
No beating physics
I think the easier way of looking at it is this: there is a Lancet commission that produces robust characterizations of the modifiable risk factors that lead to dementia. If you're in a marriage that promotes reducing those risk factors, you'll likely have a lower risk of dementia. Isolating one variate like this raises interesting questions, but isn't a "smoking gun'-- especially in this case since the authors themselves indicate this is a surprising result given other studies.
Seems just as reasonable but less verbose; we appear to get cancer and mental illness with old age regardless of social conditions around us. Physics and entropy win again regardless of the care we put into our semantics.
Regardless my original point was about "long term".
"Marriage staves of mental health" and "a single, long term marriage improves mental health outcomes" are two different things.
Could just be a tight knit quasi-nuclear family social circle is sufficient too but social desirability biases lead is to lean into marriage tradition.
Source: dude trust me
Tell that to all the animals that exhibit long-term, often life-long coupling.
Lots of animals engages in non consensual rape; humans need to get on a level?
Don't anthropomorphize ducks.
Codependency to survive altogether is different than "2 people stuck together by social pressure even if its not working for them" which happens a lot to marriage often becomes unnatural abuse.
Unlike ferrets we engineered around raw need to hunt rabbits; we have grocery stores to serve the codependency.
It came from the past so it's natural is a terrible argument. Just a "dude trust me; its how grandpa did it"
With the decline in religious attendance has come a decline in marriage; from 70%+ to 50%ish over the last couple generations
But divorce rate has declined so those that do marry seem to really want it; in the before times though it was how women survived
Coupling fits with biological imperative to have partners but longterm/for life is obviously not necessary since divorce is common too, partners die, etc
That and recent research shows long term married couples are 50% more likely to develop dementia; an imbalance in effort develops where one becomes codependent and forgets how to live and the partner in charge loses grip of themselves and taking care of their partner consumes them.