It is possible to improve symptoms in autistic children with a cheap generic drug, our latest study shows. The drug, bumetanide, is widely used to treat high blood pressure and swelling, and it costs no more than £10 (US$13) for a month's supply of pills.
Autism is a neurodevelopmental disorder which is more common in boys than girls. According to the World Health Organization, 1-2 percent of people have the condition.
Autism can be diagnosed as early as two years old or even at 18 months. Children with moderate or severe autism can find social situations difficult. They may not make eye contact with their parents or take part in cooperative play and conversation.
They may also show repetitive behaviour and have an intense interest in objects. This behaviour not only affects engagement in family activities but can also make it harder for them to make friends at school.
International study
We were motivated to test bumetanide as a result of background findings which suggested that the drug changed important brain chemicals in mouse models of autism; and also by some studies, including in autistic teenagers, showing that bumetanide may have beneficial effects.
Our research group, an international collaboration between researchers at several institutions in China and the University of Cambridge, wanted to focus on young children with moderate and severe autism and to test whether bumetanide could improve their symptoms.
We also wanted to understand the mechanism by which the drug achieved this. Understanding how bumetanide worked could lead to future drug development to treat moderate and severe autism.
There were 81 children with moderate to severe autism in our study – 42 in the bumetanide group, who received 0.5mg of bumetanide twice a day for three months; and 39 children in the control group, who received no treatment. The children were three to six years of age.
Some of the children had their brains scanned using magnetic resonance spectroscopy (MRS) – 38 in the bumetanide group and 17 in the control group.
MRS is a non-invasive way of measuring chemicals in the brain. For our study, we measured brain chemicals called GABA and glutamate, which are important for learning and brain plasticity (the brain's ability to change and adapt as a result of experience).
In the bumetanide group, autism symptoms improved as measured by the childhood autism rating scale (CARS) and also by a doctor's overall impression. The doctors who were assessing symptom change were "blind" to treatment – that is, they were unaware of who was receiving bumetanide.
Improvements in symptoms were associated with changes in the brain chemicals GABA/glutamate ratios and, in particular, with decreases in GABA.
Looking specifically at what improved on the rating scale, we found decreases in repetitive behaviour and decreased interest in objects. These reductions in unsociable behaviour allow more time for increases in social behaviour.
One of the mothers of a four-year-old boy, living in a rural area outside Shanghai, said that her child, who was in the bumetanide group, became better at making eye contact with family members and relatives and was able to take part in more family activities.
We also found that the drug is safe for young autistic children and has no significant side-effects. Bumetanide could improve the quality of life and wellbeing of autistic children.
Existing treatments are predominantly behavioural, including Applied Behaviour Analysis or ABA. Most families, particularly those in rural areas, will have limited or no access to these treatments, which are generally only available in specialised centres. The use of bumetanide would mean that there would even be a treatment for autistic children living in rural areas.
This study is important and exciting because bumetanide can improve social learning and reduce autism symptoms when the brains of these children are still developing. We now know that human brains are still in development until late adolescence and early adulthood.
Further research is now needed to confirm the effectiveness of bumetanide in treating autism. 
Barbara Jacquelyn Sahakian, Professor of Clinical Neuropsychology, University of Cambridge and Christelle Langley, Postdoctoral Research Associate, Cognitive Neuroscience, University of Cambridge.
This article is republished from The Conversation under a Creative Commons license. Read the original article.