A new drug that helps to ease the symptoms of autism has been found to be successful in animals, and could offer new hope for humans who struggle with the condition, a team of researchers in France has reported.
In the study, researchers found that bromide ion treatment helped to improve interactions, limit repetitive behaviours, and reduce anxiety among autistic test subjects.
The findings were published in the April 2022 issue of the scientific journal Neuropsychopharmacology.
The researchers looked at three different mouse models of autism from across the spectrum, over a long time period, and found improvements in mice that had autistic-type neurodevelopmental issues.
The study comes from researchers at several establishments, including public health research group Inserm, national research centre the CNRS, food and environment research institute INRAE, and the University of Tours.
Dr Julie Le Merrer, co-author of the study and research director at the CNRS, said: “We tested the effect of bromide ions on mice.
“In autism, there is a change in the balance between excitation and inhibition in the brain. We tested this molecule, which inhibits the brain, on three models of autistic pathology with different mechanisms. We then carried out the most precise behavioural analysis possible on these mice.
“And we observed…a reduction in the stereotyped behaviour of the animals: the mice made fewer circles around themselves.”
The mice also showed fewer symptoms of anxiety.
Next steps in the trials
For the time being, the research is only at a pre-clinical stage, meaning it is only being tested on animals. Further tests will be needed to see if humans respond in the same way to the drug.
Human trials have not yet been confirmed.
Dr Le Merrer said: “We've reached a major challenge. So far, autism research has not been very successful, so these initial results are no guarantee of success.”
Recent studies on the effects of drugs including balovaptan, oxytocin and bumetanide have been unsuccessful.
Professor Frédérique Bonnet-Brilhault, head of the psychiatry department at the Tours University Hospital and head of the Centre d’excellence autisme in France, told 20 Minutes: “There have been many disappointments over the past two years.
“This discourages laboratories from investing in autism research, even though there is a real need for it. Autism is the only field of medicine where therapy concerns the re-education of language and motor skills, but we are sorely lacking in a therapeutic arsenal [of medicine].”
Bromide ions will need to be tested with care, due to the risk of side effects, the researchers said.
Dr Le Merrer explained: “There is no addictive effect, but from certain doses onwards we can see a sedative effect, disturbance, and skin rashes.
“As soon as we see the first signs, we stop and they disappear. The problem is that with this drug the margin between effective and toxic dose is small.”
It is thought that the drug could be administered via oral drops, especially for young children, for whom tablets are not suitable.
A complement to existing treatment
Even if the drug is successful and eventually approved for use in humans, “the treatment would not replace behavioural approaches used today…but would complement them”, explained Jérôme Becker, researcher and head of the child psychiatry department at the University of Tours.
He said: “We are not going to cure the condition, but could make life easier for patients, especially adults. We will first target children and adults with a major disability.”
Autism affects around 700,000 people in France, of which two-thirds are adults. There is currently no medicine available specifically to treat autism.