The first time Ditzen and her colleagues did this experiment they found that for both men and women oxytocin improved communication and lowered cortisol, a stress hormone. But in a recent study published in Social Cognitive and Affective Neuroscience, Ditzen and her colleagues measured salivary alpha-amylase (sAA)—an enzyme tied specifically to social stress—and found that men and women responded differently. Women who got oxytocin showed a decrease in sAA whereas men showed an increase and reported feeling more intense emotions. Counterintuitively, these men were also better at communication during conflict: they smiled more, had more eye-contact and were more open about their feelings. These behaviors are essential for peaceful conflict resolution.
Unlike previous studies, the trial will include people with a wide range of symptoms — and one of its major aims is to uncover the set of factors that influence whether and how strongly people respond to oxytocin. Sikich will analyse many measures of cognition and social functioning, and collect blood samples to look for biomarkers — such as levels of oxytocin and the receptor it binds to — that are associated with a response. “Lin has really been trying to create conditions under which you could study the potential beneficial effects of oxytocin and really do this right,” says Carter.
Adam Guastella, a clinical psychologist at University of Sydney’s Brain and Mind Research Institute, and a pioneer in studies of how oxytocin can help people with autism, thinks the hormone can also help people in couple therapy by facilitating empathic communication. His research has shown that people who get oxytocin are more focused on positive emotion: they remember happy faces better than angry and neutral ones. Research by others has shown that oxytocin increases trust, generosity and our ability to identify emotion in facial expressions. It is perhaps by these mechanisms that the hormone improves communication.
Affecting generosity by increasing empathy during perspective taking. In a neuroeconomics experiment, intranasal oxytocin increased generosity in the Ultimatum Game by 80% but has no effect in the Dictator Game that measures altruism. Perspective-taking is not required in the Dictator Game, but the researchers in this experimental explicitly induced perspective-taking in the Ultimatum Game by not identifying to participants which role they would be in.13
Potential side effects of 5-HTP include heartburn, stomach pain, nausea, vomiting, diarrhea, drowsiness, sexual problems, vivid dreams or nightmares, and muscle problems. Because 5-HTP has not been thoroughly studied in a clinical setting, possible side effects and interactions with other drugs are not well known. According to the US National Institute of Health TOXNET, 5-HTP has not been associated with serotonin syndrome or any serious adverse events in humans. Across multiple studies, 5-HTP also been reported to not cause any noticeable hematological or cardiovascular changes. 5-HTP also has not been associated with eosinophilia.