This was a fun one. One relevant study that I really hoped would be discussed here, but wasn't, was Eichhorn, J. (2011). Happiness for Believers? Contextualizing. It evidenced that, as one writer on the Patheos website summarized it, "religion only makes for happy people if there’s a lot of it about." So, if the quantity of believers affecting happiness wasn't controlled for in the large body of research mentioned by Dr. Koenig (and I suspect it wasn't, in any of them), then that could be potentially devastating confounding variable. I hope future debates on this topic will consider this.

This was an interesting discussion. However, it would be impossible to argue that any one thing - even a big thing like religion - would be an effective "cure" for the loneliness of millions of people. One could just as well suggest that it would help if lonely people joined bowling leagues, or any structured social activity. Secular social activities don't have the heavy baggage of religion, such as obedience to an external moral authority and a moral code partly based on ancient beliefs. Religion has another elephant in the room. If religion was even half as good as claimed for people's happiness and health, why has religious participation been declining so rapidly over the decades? Human nature can be quirky, but most people don't quit doing something that makes them happy. As pointed out by Ruth and Dan, religion is, often enough, divisive, exclusive, and even hateful. Sadly, this problem is a feature of religion, not a bug. One can't prescribe a cure that is likely to poison half of its patients. Of course, the other unstated problem is which religion should be prescribed. Is Christianity the default in the US? Which denomination of Christianity? Harold and Chris are both Protestants, I think. Do we encourage lonely people to try out a few religions to see which one fits? Do churches really want people to join for social reasons rather than religious reasons?