. . . can be found here. The article begins with the observation that women report less happiness than men in being with their own parents and speculates that the reason for this is that, for women, being with parents often means work. But I must say that in my own life, my parents are one of my greatest sources of joy and I almost never feel "stress" when I’m around them. Of course, they are young and so don’t yet need my help. Indeed, when I’m with them, I work less! They take over with the kids and insist that I do other things--like shop unencumbered or read a book uninterrupted. I hope I will remember how good they have been to me when they do need my help.
How do you measure happiness? This is extremely subjective.
Is happiness and contentment the same thing? Might it be these studies are gauging discontent and calling it unhappiness?
When your parents come to need help, like children, but NOT like children, the relationship changes and becomes very difficult. To find the balance between due honor and respect and an efficient care for their infirmities, especially when those are mental, not physical, is very difficult.