Hard to say really, but independent research shows Utah is the most depressed state in the country. People have controversially tried to show that there is a correlation between depression and the Mormon faith. Technically at this stage, the reason behind Utah’s mass depression is unknown.
Some experts say that there is a cultural factor involved, in particular among Mormon women who have to put on a mask of perfection to look like a good mother and wife. They can’t show their tears, depression or agony. Perfectionism leads people to depression because its a standard that just can't be reached.
I remember certainly as a missionary and at other times as a mormon that I tried to look perfect for others even when I was troubled. I remember coming back home and taking a role as Ward Exec Sec and finally realising that all those families who I thought were perfect, were actually struggling and miserable, as I sat in on Bishopric and PEC discussions.
I would suggest that those families that seem happy, are probably like me and you. Just human, with their own battles, but at least putting on a happy front. After all, they're commanded to be happy, are they not?