Whenever the topic of happiness is mentioned, it's always discussed like it's the most important thing in the world. People talk about it like they would a hidden treasure or a rare beast - you have to seek it, hunt it, ensnare it and hold it tight, or it'll slip through your fingers. Perhaps it's just the contrarian in me, but this seems misguided - happiness shouldn't be searched for like the holy grail. Not that I don't want to be happy, but is that really the purpose of my life - to have my neurons stimulated in a way that feels good, and try to keep that up until I die? Why don't I just slip myself into a Soma-coma then? Of course, anything I do boils down to a particular stimulation of neurons, but that doesn't mean there's not something better to aspire to. To pursue happiness as an end itself I think, is backwards. It wasn't built into our brains because evolution was being nice - it's there because it increases our fitness. Happiness is designed to get us somewhere, not to be a destination in itself.
Sorry for the delay in getting back to you (in fairness, you didn't get back to me either!). A good paper (though not a meta-analysis) on this is:
Stutzer and Frey (2006) Does Marriage Make People Happy or Do Happy People Get Married? Journal of Socio-Economics 35:326-347. links
The lit review surveys some of the other evidence.
I'm a little puzzled by this comment given that the first link you provided looks (on its face) to be based on exactly this sort of evidence. But in any event, many of the studies mentioned in the Stutzer and Frey paper look at health and other outcomes as well.
Thanks.
By doubt I just mean it's really really easy to get it spectacularly wrong in a systemic way in too many ways, so I'm only going to believe the result if it's robust with wide variety of tests and situations. Not that there's no value in it.