There is an interesting post on Brain Wave related to country-wide differences in conditions that lead to higher level of oxytocin /estrogen and how these levels of oxytocin are correlated to the level of trust.
As per the study, some factors like the consumption of healthy food consisting of vegetables and fruits, and other factors like clean environments are directly related to average levels of Oxytocin in the population. Also, the same factors are shown to be correlated to levels of trust in the population. It is instructive to note here, that Oxytocin mediated Tend-and -Befriend response to stressful situations has been posited in females as opposed to fight-or-flight (male) response.
What is even better is that Trust and happiness are found to be correlated. Moreover, greater levels of trust are correlated with better economic environment. Thus, a sure way for a country to become both prosperous and happy is to focus on factors that raise the national Oxytocin levels – HUGS and fresh vegetables and foods!