Investigators at our ATN center in Missouri are pioneering research into the potential benefits of the beta-blocker propranolol
By neurologist David Beversdorf. Dr. Beversdorf specializes in cognitive and behavioral neurology and runs the adult and adolescent autism spectrum disorders clinic at the University of Missouri’s Thompson Center for Autism and Neurodevelopmental Disorders. The Thompson Center is one of 14 sites in the Autism Speaks Autism Treatment Network.
Earlier this month, Dr. Beversdorf and his research team published a small but carefully conducted study showing that one dose of the commonly used blood pressure medicine propranolol temporarily improves conversational skills in adults with autism. (Read our news report here.)
We invited Dr. Beversdorf to write about the growing interest in this treatment and how it might be used to help people with autism in the future.
The drug propranolol was originally developed to help control high blood pressure and heart rate. Like other beta-blocker drugs, it blocks certain receptors for noradrenaline, a powerful hormone involved in the body’s response to stressful situations.
Propranolol also crosses into the brain to produce a calming effect. For this reason, it’s been used “off label” for decades to ease performance anxiety – including test anxiety and nervousness around public speaking.
Early interest in beta blockers for autism
In 1987, researchers at Harvard Medical School published the results of a small study with eight participants who had autism. The researchers found that, after starting propranolol, the men showed improvements in their speech and sociability. All the study participants were verbal, and none had intellectual disability.
However, the study was not blinded. In other words, both the researchers and the study participants knew that the men were taking a drug that would hopefully improve language skills. As you can imagine, expectations could well have influenced the results. We call this “the placebo effect.”
Since then, my colleagues and I have conducted several, more-controlled studies using propranolol with teens and adults who have autism. Again, all the participants were both verbal and free of intellectual disability.
In all of these trials, we compared spoken language skills following a dose of propranolol compared to a placebo, or dummy pill. Importantly, neither participants nor researchers knew when a participant was getting the active medicine versus the dummy treatment until after the test results were in.
In our new study, we went beyond measuring language skills to see if propranolol could also improve conversational reciprocity. By “reciprocity,” we mean the appropriate back-and-forth flow of a responsive conversation. This skill is a great challenge for many people affected by autism.
My graduate student Rachel Zamzow led the study. We recruited 20 teens and young adults who had autism and were being seen at the Thompson Center.
During the first session of the trial, half the volunteers took a 40-milligram dose of propranolol and the other half took a look-alike dummy pill. An hour later, each participant had a structured conversation with one of the researchers.
The investigator rated the exchange in terms of six social skills important for maintaining a conversation: staying on topic, sharing information, shared conversation, transitions or interruptions, nonverbal communication and maintaining eye contact.
During the second session of the study, those who received propranolol received the placebo, and vice versa. This ensured that the order of testing did not influence the results. It also gave us two sets of test results for each participant.
When we broke the code to find out when each participant took the propranolol, we found that the medication significantly improved overall communication scores compared to the placebo. These scores included both language skills and conversational reciprocity.
Not yet ready for clinical use
While the results show promise, we caution that the results from this single-dose experiment are too preliminary for us to recommend using the medicine to improve communication skills in people who have autism.
Instead, the purpose of this study was to establish what behaviors appear to respond to propranolol – at least in the short term. This information is vital for guiding larger, longer and more comprehensive clinical trials.
We hope to soon move forward with a trial that will allow us to determine whether sustained use of propranolol will produce sustained benefits for people with autism.
Furthermore, we want to explore how to predict who is most likely to respond to the drug, as well as assess the risk for unwanted side effects.
We would like to thank the participating families and the Thompson Center for participating in our research. We also thank the U.S. Health Resources and Services Administration for funding this project through the Combating Autism Act. Research funding such as this is critical for the future advancement of autism research.
In addition to Rachel Zamzow, our team included graduate student Bradley Ferguson, of the University of Missouri Interdisciplinary Neuroscience Program; Janine Stichter, Ph.D., with the University of Missouri Department of Special Education; Eric Porges, Ph.D., with the Department of Aging and Geriatric Research at the University of Florida; and undergraduate students Alexandra Ragsdale and Morgan Lewis, of the University of Missouri.