Oxytocin, a hormone best known for activity during birth and lactation, is also a brain neurotransmitter involved in social recognition and bonding and, according to first round research, may have significant positive effects on adult autism patients.
A new study, funded by the Seaver Foundation, examined the effects of oxytocin on repetitive behaviors and aspects of social cognition in adults with autism. The hormone was administered using intravenous fluid and nasal technology to allow better penetration of the blood brain barrier, a membrane that serves as a physical barrier between the blood vessels and the central nervous system.
“When administered orally, oxytocin is metabolized and only a small amount reaches the brain. This is important because the behavioral effects of oxytocin are thought to result from its action on the brain”, explained investigators Eric Hollander, MD and Jennifer Bartz, PhD.
“Studies with animals have found that oxytocin plays a role in a variety of behaviors, including parent-child and adult-to-adult pair bonding, social memory, social cognition, anxiety reduction and repetitive behaviors,” explained Dr. Bartz.
“However,” adds Dr. Hollander, “we have only recently considered that administration of oxytocin can have behavioral effects. Autism is a particularly ripe neuropsychiatric disorder for studying this approach because it presents with the types of symptoms that have been found to be associated with the oxytocin system.”
High-functioning adults with autism or Asperger’s disorder received an intravenous infusion of pitocin (synthetic oxytocin) or placebo (saline solution) over a four-hour period. During that time, participants were monitored for repetitive behaviors that are hallmarks of autism spectrum disorders including need to tell/ask, touching, and repeating. These behaviors were assessed at a baseline and throughout the course of the infusion.
“Repetitive behaviors are often overlooked as symptoms of autism in favor of more dramatic symptoms like disrupted social functioning,” noted Hollander. “However, early repetitive behavior is often the best predictor of a later autism diagnosis.”
The infusion produced results that were both clinically and statistically significant. Hollander noted a rapid reduction of repetitive behaviors over the course of the oxytocin infusion, whereas no such reduction occurred following the placebo infusion, suggesting that oxytocin does indeed address these symptoms.
Researchers also looked at the effects of oxytocin on social cognition. Autism patients are often unable to detect or read emotion in others through facial and voice cues, resulting in the decreased ability to have meaningful interactions with others that characterizes individuals with this disease.
To test participants’ ability to assign affective significance to speech, participants listened to pre-recorded sentences with neutral semantic content that were presented with different intonations such as anger, sadness, or happiness. Participants were asked to identify the emotion. Participants received intravenous infusions of pitocin (synthetic oxytocin) or placebo (saline solution) over a four-hour period; participants then returned approximately two weeks later, receiving the alternate compound. Comprehension of affective speech was assessed throughout the four-hour infusion on both occasions, that is, once with intravenous infusion of oxytocin and once without.
Most interestingly, participants who received oxytocin on the first testing day retained the ability to assign affective significance to speech, performing above expectations when they returned approximately two weeks later. This effect was not found among participants who received the placebo on the first testing day.
Hollander and his colleagues are now using nasal technology to study the treatment implications of oxytocin in a controlled six week trial. “The intranasal administration of oxytocin is important because it may allow for better penetration of the blood brain barrier, and is easier to administer,” explained Hollander. “When administered orally, oxytocin is metabolized and only a small amount reaches the brain. This is important because the behavioral effects of oxytocin are thought to result from its action on the brain.”
Hollander and his colleagues are among the first group to have used intravenous fluid technology and nasal technology to study the behavioral effects of oxytocin in autism spectrum disorders. Though the findings are promising, Hollander cautions that this research is still very preliminary.
“Our findings will need to be replicated in large scale, placebo controlled trials to fully explore treatment potential,” said Hollander. “And, though both intravenous and intranasal approaches have been well tolerated, we need to understand more about the safety of these potential treatments, particularly before these effects are explored in autistic children.”