A Allele In The Fatty Acid Amide Hydrolase

Science Daily: Genes may contribute to making some nations happier than others - First study to show link between genetic make-up and perceived national happiness

summary - The citizens of nations that rate themselves happiest display a specific genetic feature: their DNA is more likely to contain a specific allele involved in sensory pleasure and pain reduction, say researchers. They weighed up genetic and various external factors to might contribute to national differences in happiness.