Effects of Long-term Oxytocin Use in Children

Dr. Karen Bales, CNPRC Brain, Mind, and Behavior (BMB) Unit Leader, has done extensive research on the hormone oxytocin and its short and long-term effects on behavior in two monogamous species – prairie voles (Microtus ochrogaster) and titi monkeys (Callicebus cupreus). She is particularly interested in the role of neuropeptides such as oxytocin and vasopressin in social bonding and male parental care, as well as the effects of early experiences on the development of these behaviors. Dr. Bales’ research has been in a wide range of publications, from an airline magazine for Valentine’s Day, to many online public interest stories, to countless peer-reviewed journals, including the current issue of Science (The Promise and Perils of Oxytocin, by Greg Miller, Science 18 January 2013: Vol. 339 no. 6117 pp. 267-269). Her co-authors include Dr. Sally Mendoza, also a BMB Core Scientist, as well as Dr. Marjorie Solomon of the UC Davis MIND Institute, Dr. Suma Jacob of the University of Minnesota, UC Davis Psychology graduate students Allison Perkeybile and Olivia Conley, and UC Davis undergraduates Griffin Downing, Caleigh Guoynes, Meredith Lee, and Catherine Yun. At the time of the research, Ms. Lee was a student at John F. Kennedy High School in Sacramento.

Author Greg Miller of Science, writes “Few substances produced by the human body have inspired as much hoopla as oxytocin. Although breathless media coverage often goes too far, it reflects a genuine and infectious excitement among many scientists about the hormone’s role in social behavior: promoting trust and cooperation and making people more attuned to social cues. At first glance, oxytocin might seem like just what the doctor should be ordering. But as researchers have continued to explore the hormone’s effect on human behavior, a darker side has emerged.”

Discussing the history of research with oxytocin, and addressing the question if the current jump to long-term human clinical trials with autistic children is premature, Miller includes Dr. Bales’ research and her concerns about giving children hormones whose effects have not been studied in the long-term. From her past research, Dr. Bales knows that even a single dose of oxytocin can have long-lasting effects; “The clearest message was that any exposure to oxytocin can cause long-term behavioral and neuroendocrine effects”.

“There’s been this quick leap from looking at a single dose of oxytocin in healthy adults to trying to give it to children with autism whose brains are still developing,” she says. Dr. Bales hasn’t found a single published study on the long-term behavioral effects of multiple doses of oxytocin in developing animals. “It seemed to me that we are really skipping a step.”

Recently Dr. Bales and colleagues tried to better mimic the type of oxytocin treatment now in clinical trials for autism, giving young prairie voles daily squirts of oxytocin in the nose for 3 weeks. In developmental terms, Bales says that the voles were roughly equivalent to 12- to 17-year-old children. In the short term, oxytocin made the voles more social, as expected. As adults, however, treated males had abnormal relationships with their partners. Several currently proposed clinical trials plan to administer oxytocin to children in this age group.

To Dr. Bales, her research findings raise the troubling possibility that repeated use of oxytocin nasal spray may cause long-term changes in the brain that negate or even reverse the hormone’s benefits, perhaps by tricking the brain into making less oxytocin of its own.

Out of frustration that science is moving too slowly, parents of autistic children have been willing to try experimental treatments, even before they’re fully vetted by researchers. At the same time, Dr. Bales hopes that science won’t let these families down again by rushing too quickly into clinical trials with a hormone whose effects aren’t adequately understood.

Dr. Bales’ research is funded by a grant from the National Institute of Child Health and Human Development (NICHD), which includes follow-up studies of chronic intranasal oxytocin administration in monkeys.