Many studies trumpet the positive effects of oxytocin. The hormone facilitates bonding, increases trust and promotes altruism. Such findings earned oxytocin its famous nickname, the “love hormone.” But more recent research has shown oxytocin has a darker side, too: it can increase aggression, risk taking and prejudice. A new analysis of this large body of work reveals that oxytocin's effects on our brain and behavior actually look a lot like another substance that can cut both ways: alcohol. As such, the hormone might point to new treatments for addiction.
Researchers led by Ian Mitchell, a psychologist at the University of Birmingham in England, conducted the meta-analysis, which reveals that both oxytocin and alcohol reduce fear, anxiety and stress while increasing trust, generosity and altruism. Yet both also increase aggression, risk taking and “in-group” bias—favoring people similar to ourselves at the expense of others, according to the paper published in August in Neuroscience and Biobehavioral Reviews.
The scientists posit that these similarities probably exist because oxytocin and alcohol act at different points in the same chemical pathway in the brain. Oxytocin stimulates release of the neurotransmitter GABA, which tends to reduce neural activity. Alcohol binds to GABA receptors and ramps up GABA activity. Oxytocin and alcohol therefore both have the general effect of tamping down brain activity—perhaps explaining why they both lower inhibitions.
Clinical trials have uncovered further interplay between the two in demonstrating that a nasal spray of oxytocin reduces cravings and withdrawal symptoms in alcoholics. These findings inspired a new study, published in March in the Proceedings of the National Academy of Sciences USA, which suggests oxytocin and alcohol do more than just participate in the same neural pathway: they may physically interact. The researchers showed that oxytocin prevented drunken motor impairment in rats by blocking the GABA receptor subunit usually bound by alcohol. Mitchell speculates this interaction is specific to brain regions that regulate movement, thereby “sparing the usual motor deficits associated with alcohol but still influencing social and affective processes.”
These findings suggest getting “love drunk” may impede a person from getting truly drunk—or at least make getting drunk less appealing. They also offer a possible biological explanation for why social support is so effective at helping people beat addictions. The researchers' biggest hope for now is that in the near future, the similarity between these two chemicals will allow scientists to develop oxytocin-based treatments for alcoholics.