June 6, 2023

Oxytocin is a hormone that plays a critical role in social bonding and attachment. In recent years, researchers have been studying the effects of intranasal oxytocin, a non-invasive treatment that reduces social impairment in several neurological and behavioral disorders, such as autism.  

However, the long-term effects and efficacy of the treatment are currently under examination. Studies conducted by Dr. Karen Bales’ lab at the California National Primate Research Center reveal that chronic intranasal oxytocin produces sex-specific biological and behavioral responses in titi monkeys, a monogamous nonhuman primate.  

The researchers found that all OT-treated monkeys engaged more in social interactions but differed in their social behavior by sex. The males exhibited more social interest in unfamiliar animals, while females directed their interest toward their parents.  

The monkeys were divided into two groups: one received a daily dose of intranasal OT, while the other received saline for six months. The treatment group exhibited more prosocial behavior in their home enclosure immediately following their dose than the control group. 

Researchers also examined neural effects and social behavior during adolescence and into adulthood one-year after treatment ended. As adults, males from the treatment group maintained some prosocial effects. They also scored higher on several measures of affiliative behavior than the control group. Females, however, experienced a slight delay in forming a bond with their new mate. 

The researchers observed that chronic treatments during adolescence altered their behavior long-term, and these behavioral changes were different for males and females. These findings emphasize the complexity of the treatment and lay an essential foundation for more research on its use in humans. 

A collaborator on the project, Dr. Suma Jacob from the University of Minnesota Medical School, explained that “there is more research to be done on oxytocin, how it works, its effects, and feedback systems.”

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