Love hormone oxytocin 'mimics effects of cannabis'
A brain chemical known as the "love hormone" makes people more sociable by mimicking the effects of cannabis, say scientists.
Oxytocin is known to enhance bonding between lovers and between mothers and their babies, and to boost the pleasure of social contact.
The new research, conducted on mice, found that higher levels of the hormone in the brain led to the release of anandamide - an "endocannabinoid" similar to the psychoactive ingredient in cannabis.
Blocking anandamide also reduced the pro-social effects of oxytocin. But a drug that preserved anandamide in the brain made the animals more sociable - they appeared to enjoy the company of their cage-mates more than untreated animals.
Scientists are investigating the use of oxytocin as a possible treatment for autism, but it is very hard to deliver the protein to the brain.
Another strategy might be to intervene further down the oxytocin-anandamide pathway, the researchers believe.
Dr Daniele Piomelli, from the Italian Institute of Technology in Genoa, Italy, said: "Our findings open the exciting possibility that drugs that block the degradation of anandamide, which are currently being tested for various anxiety disorders, could give a boost to the brain's own oxytocin and help people with autism socialise more."
A small number of neurons in the brain make oxytocin. When the scientists stimulated those neurons they saw an increase in anandamide production in the nucleus accumbens brain region.
Anandamide attaches to the same brain cell receptors as the psychoactive ingredient in cannabis, THC, producing a similar "high".
The findings are published in the journal Proceedings of the National Academy of Sciences.