Oxytocin Therapy May Benefit Cocaine-Addicted Men, But Not Women
A new study finds that oxytocin, a hormone produced naturally in the hypothalamus, has a different effect on men and women when used as a treatment for cocaine-addicted individuals with a history of childhood trauma.
Previous research has shown that oxytocin can ease addiction and cravings that could result in a relapse while also reducing brain activity associated with stress. Still, it was not yet known how oxytocin influenced cravings induced by the sight of cocaine paraphernalia or whether gender-based differences existed.
To understand the role of oxytocin in addiction, it is important to study the changes that can occur in the brain in response to environmental factors, according to researchers. Extremely traumatic events such as childhood abuse can lead to post-traumatic stress disorder (PTSD), which can change neural connections within the brain.
Addiction can also lead to changes in brain connections; and the areas changed by both trauma and addiction can overlap.
The amygdala, one region in the brain that experiences these changes, is rich in oxytocin receptors and can become hyperreactive in response to stress, say researchers. While oxytocin has been shown to reduce amygdala activity in response to stress cues, less was known about how oxytocin might affect cocaine cravings in addicted individuals.
To test the craving response, a team of addiction researchers at the Medical University of South Carolina (MUSC) asked 67 study participants, while in an MRI, to view images of drug paraphernalia alongside images of more mundane items.
Viewing images of drug paraphernalia led to the amygdala “lighting up” in drug-addicted men, correlating to an increase in cravings for cocaine. Next, the participants were treated with either oxytocin or a placebo, and the researchers measured its effects on the amygdala.
In men with a history of trauma, the response was as predicted. Oxytocin reduced the activity within the amygdala, as well as the cravings that the individuals felt for cocaine, consistent with previous studies demonstrating the hormone’s therapeutic effect.
Surprisingly, this did not hold true for women with a history of trauma. While the amygdala of men with cocaine addiction would become highly active in response to visual drug cues, that of women with cocaine addiction and a history of trauma showed little activity.
“When the women with trauma were viewing the cocaine cues on placebo, they didn’t have a strong response to begin with, which was surprising,” said Jane E. Joseph, Ph.D., a professor in the Department of Neuroscience.
“In fact, the treatment with oxytocin led to the response in the brain to drug paraphernalia being enhanced and exacerbated.”
Historically, cocaine-addicted women tend to have worse treatment outcomes compared to their male counterparts. This study clearly points to the need to flesh out the trauma-induced changes in the brain, explore how they differ by gender and better understand how they affect addiction.
It also suggests that treating women with a history of childhood trauma with oxytocin alone might increase both amygdala activity and cravings, potentially leading to a higher incidence of relapse.
“Even though more men use cocaine, it really has more devastating effects on women when they relapse, and they’re much more sensitive to cocaine,” said Joseph.
Joseph offers several potential explanations for the study’s surprising findings. Men may be more susceptible to the visual cues of drug paraphernalia and the cravings that they induce. In contrast, women may be more susceptible to “stress-associated” cues, such as visuals that relate to past traumas, which could increase amygdala response.
Alternatively, women might have a blunted response in the amygdala to stress and cravings as a result of changes that could occur in response to the initial trauma-induced hyperreactivity. However, as this study only looked at drug cues and craving responses, these hypotheses must be tested in future studies.
Current therapies for addiction may not have been developed with attention to how gender affects treatment responses, perhaps accounting in part for the increased rates of treatment failures in women.
Better understanding of the intricacies of trauma, addiction and gender differences could move addiction researchers one step closer to finding effective and personalized therapies for everyone.
“The search for a medication to treat cocaine use disorder has been unsuccessful to date,” said Kathleen T. Brady, M.D., Ph.D., a professor in the Department of Psychiatry and Behavioral Sciences and MUSC vice president for research.
“Exploring subgroups of individuals, such as those with childhood trauma, and agents with novel mechanisms of action, like oxytocin, is critical to moving the field forward.”
The findings are published in the journal Psychopharmacology.
Pedersen, T. (2020). Oxytocin Therapy May Benefit Cocaine-Addicted Men, But Not Women. Psych Central. Retrieved on February 28, 2020, from https://psychcentral.com/news/2020/01/20/oxytocin-therapy-may-benefit-cocaine-addicted-men-but-not-women/153432.html