We will test medicines to see if they can help autistic people who want them

This work has included testing medicines to see if they can help autistic people who want them. 

Clinical trials ensure that medications are effective and safe. We ran a clinical trial with a medicine called arbaclofen. Previous studies showed that this medication is safe and suggested that it may improve social difficulties in autistic children and adolescents who have fluent language.  

122 autistic children and adolescents between 5-17 years old were included in this study, from 7 European sites (three in UK, one in France and three in Spain). As is usual practice in clinical trials, half of the participants took a placebo (such as a sugar pill) to ensure any effects were not due to placebo effects (psychological effect where people experience physical or psychological improvement due to the belief a medication will work). The study used a double-blind design, meaning that both the participant and the research team didn’t know if the person was taking the medication or the placebo during the 16-week treatment period.  

Measures of social function, mental health and quality of life were taken before, during and after this period to look for change over time. We found that social withdrawal (a person removing themselves from interaction), and repetitive behaviours reduced, whereas peer interactions and quality of life scores increased. Social adaptive behaviour measured with the Vineland interview – a common interview used in trials for autism – was also evaluated, but this did not change with use of the medication. Contrary to previous studies, arbaclofen did not increase somnolence (feeling of being sleepy or drowsy) in comparison to placebo. However, we also found more sleep problems (other than somnolence, such difficulties falling asleep or insomnia) in those taking the medication, which needs further investigation and close monitoring in future studies or use of the medication. Further larger scale studies are needed to test the potential of arbaclofen.  

In November 2025 we initiated a second arbaclofen trial. Our aim is to run a follow up study to further investigate characteristics of those that responded most to the medicine and test the effectiveness of further use of the medicine. This could help with identifying those that might respond more to the medication in the future which could help inform decision making for individuals and families regarding the use of this medication.  

Full paper on the arbaclofen clinical trial can be read here: 

Parellada, M., A. San José Cáceres., R. Delorme., et al (2026). Efficacy, safety, and tolerability of arbaclofen in Autistic children and adolescents, the AIMS-2-TRIALS-CT1: a randomized, double-blind, placebo-controlled phase II trial. eClinicalMedicine. February 2026. 

 

Other studies investigating medications 

We have also tested medicines that might help autistic people with social interactions or repetitive behaviours. These medicines had previously been approved for other uses and work on naturally occurring chemicals that transmit messages in the brain, called neurotransmitters.  

– A medicine that targets GABA (led by Kings College London and University of Coimbra) 

– A medicine that targets serotonin (led by Kings College London and University of Coimbra). 

These research projects were conducted to help create options for those who want support. We acknowledge and recognise not everyone wants medical and/or drug treatment and intervention. 

 

Barriers and pathways to treatment and interventions

A wider aim of the project was to improve the design of clinical trials by identifying indicators (called biomarkers) of who is likely to benefit from a particular treatment. More details on this work can be seen on our biomarkers pages.  

We also looked at economic barriers to the development of new treatments in autism and autism with co-occurring epilepsy. More details of this can be seen in the papers below. 

Tinelli M, Roddy, A., Knapp, M. et al. (2023). Economic Evaluation of anti-epileptic Medicines for Autistic Children with Epilepsy. Journal of Autism and Developmental Disorders. 1-9.

Tinelli M, Roddy, A., Knapp, M. et al. (2023). Economic analysis of early intervention for autistic children: findings from four case studies in England, Ireland, Italy and Spain. EurPsychiatry. 2023 Sep 21;1-65.