Trust hormone associated with happiness: Human study suggests new role for oxytocin

The study was presented at Neuroscience 2010, the annual meeting of the Society for Neuroscience, held in San Diego.

"Our findings reveal that the biological basis for social connections -- oxytocin -- is part of the brain mechanisms that serve to make us happy," said Paul Zak, PhD, at Claremont Graduate University in California, the senior author of the study.

Zak and his colleagues drew blood from study participants before and after they received a $24 gift from a stranger. The participants could then return to the stranger a portion of the money they received. Before any money changed hands, participants completed surveys assessing their general attitudes and dispositions.

The researchers found that the women who showed the greatest increases in oxytocin after receiving the gift were more satisfied with their lives, showed greater resilience to adverse events, and were less likely to be depressed, according to their survey responses. In addition, the women who shared the most money with the stranger were happiest, had stronger attachments to others, and trusted others more.

Although the study suggests new roles for oxytocin, it remains unclear whether oxytocin makes people happy, or if happy people release more oxytocin when trusted.

Research was supported by the John Templeton Foundation.