Being “drunk in love” is more than a poetic metaphor. Oxytocin, the famous "love hormone", can have effects that are remarkably similar to alcohol, indicating that there is a downside to what in recent years has been hailed as a wonder chemical.
Oxytocin is released during childbirth and helps mothers to bond with their children. Levels have been shown to rise when kissing and during other activities associated with romantic love, and can enhance empathy and trust. Of course, there are times when too much trust can be dangerous, but as a general rule this all sounds great.
However, the ways in which oxytocin acts, suppressing the prefrontal and limbic-cortical circuits, can resemble the effects of alcohol. A connection between the two chemicals has already been established in the quest for a sobriety pill, and Dr Ian Mitchell of the University of Birmingham wondered how far the similarities went.
"We thought it was an area worth exploring, so we pooled existing research into the effects of both oxytocin and alcohol and were struck by the incredible similarities between the two compounds,” Mitchell said. His findings were published in Neuroscience & Biobehavioural Reviews.
"They appear to target different receptors within the brain, but cause common actions on GABA transmission in the prefrontal cortex and the limbic structures,” Mitchell said. “These neural circuits control how we perceive stress or anxiety, especially in social situations such as interviews, or perhaps even plucking up the courage to ask somebody on a date. Taking compounds such as oxytocin and alcohol can make these situations seem less daunting."
Needing a little liquid reinforcement to politely ask someone out to dinner, however, can lead to drunkenly not taking no for an answer. Mitchell found the same can be true of oxytocin.
Volunteers who take oxytocin nasally in lab tests may not lose their ability to walk a straight line or enunciate clearly, but they do become aggressive, risk-taking, boastful and even show more envy. Moreover, far from being the universal love drug that makes us want to hug the world, Mitchell found people taking oxytocin become more inclined to discriminate against those they don't see as part of their circle.
Co-author Dr Steven Gillespie, also of the University of Birmingham, said, "I don't think we'll see a time when oxytocin is used socially as an alternative to alcohol. But it is a fascinating neurochemical and, away from matters of the heart, has a possible use in treatment of psychological and psychiatric conditions.”
Maybe it is oxytocin, not alcohol, that is the “cause of and solution to all of life's problems”.