In a new study, Daniel H. Geschwind, M.D., Ph.D., has shown that treating a strain of genetically mutant mice with oxytocin––the so-called “Love Hormone”––improves their ability to interact more normally with other mice. His findings, published on January 21st in Science Translational Medicine, may be important for the study of autism in humans.

Dr. Geschwind is a 1999 NARSAD Young Investigator grantee and a 2012 winner of the Foundation’s Ruane Prize for Child and Adolescent Psychiatric Research. He studies one particular mouse model of autism spectrum disorder (ASD) that has previously been shown to be a good testing ground for drugs.

Autism is exceedingly individualistic. It is currently thought to arise from a combination of environmental and very complicated genetic factors, with more than 100 “risk” genes discovered so far, each being implicated in less than one percent of cases. Yet mouse models of ASD can provide simple study tools that may be applicable to at least a portion of human cases.

Just like humans with ASD, the mutant mice studied by Dr. Geschwind and colleagues can be hyperactive, and have the core symptoms associated with ASD: repetitive behaviors and lack of sociability. And just like humans, no drugs have been found that address the social impairments in the mice. Using mice originally developed at the Weizmann Institute of Science in Israel, Dr. Geschwind’s team at UCLA treated these mice with several compounds they thought might improve social behavior.

They gave the mice two tests. In the first test, two mice were put in a cage together, and the researchers watched how much they interacted. In the second test, a mouse was put in a chamber and allowed to choose between interacting with an empty cup or a cup with another mouse in it. In both tests, the social interactions of the "autistic" mice were markedly improved when they received oxytocin. These effects lasted about two hours, and held true not only when the mice were injected with oxytocin, but also when they were induced with drugs to make more of the hormone in their own cells.

Mice given oxytocin a week after birth and daily for two more weeks showed better social interaction a full week after the treatment had stopped. In adult mice treated with oxytocin, the effect lasted only a few hours. The researchers suggest that “there may be an early developmental window during which treatment with oxytocin can achieve longer-lasting improvements in social behavior.” However, they also caution that more work needs to be done.

Oxytocin is known to be important in human bonding and other social contexts. But studies looking at oxytocin levels in people with ASD have been hard to interpret, with some showing higher levels of the hormone in affected individuals and others showing lower levels. If there are some people with autism who have genetic defects in their oxytocin system, as do the mice in this study, it’s possible they could benefit from oxytocin treatment. Although such patients have not yet been characterized, the study suggests that identifying them might have important implications for treatment.

Read the abstract.