The hormone oxytocin, which has been associated with interpersonal bonding, may enhance the pleasure of social interactions by stimulating production of marijuana-like neurotransmitters in the brain, according to a new study. The research provides the first link between oxytocin -- dubbed the 'love hormone' -- and anandamide, which has been called the 'bliss molecule' for its role in activating cannabinoid receptors in brain cells to heighten motivation and happiness.