Scientists are opening a new front against autism by using drugs to alter brain chemistry that may ameliorate the worst effects of the condition.
At least three groups are experimenting with treatments which, it is hoped, could help individuals acquire language and social skills enabling them better to communicate.
Autism, which overwhelmingly affects boys, has been described as the "extreme male brain" – characterised by a love of routine, poor social understanding, a lack of warmth and a disregard of human contact.
Drugs currently prescribed are chiefly aimed at controlling aggression and anxiety, which afflicts some of those affected. But trials of new drugs which target the classic symptoms of autism are now beginning.
Initial results from a small trial of a drug called arbaclofen, presented at the International Meeting for Autism Research in Philadelphia last week, suggest it may improve social skills in people with fragile X syndrome and autism, including communication and sociability, and reduce outbursts of irritability. Fragile X affects one in 3,000 people worldwide and is the most common genetic cause of autism, with a quarter of fragile X males affected.
Randall Carpenter of Seaside Therapeutics in Cambridge, Massachusetts, which is testing the drug, told New Scientist: "People may learn more, learn to speak better, learn social skills and to be more communicative."
The researchers were working on the hypothesis that the absence of the fragile X gene causes disorders of synaptic function – disorders at the junctions or synapses between the nerves – and that this may also be the cause of the autistic symptoms. A successful treatment for fragile X may therefore also be effective in alleviating autistic symptoms. The trial involved 63 subjects aged between six and 40.
Elizabeth Berry-Kravis, who led the study at Rush University Medical Centre in Chicago, earlier treated a separate group of fragile X patients with a different drug, fenobam. Some patients showed calmed behaviour, reduced hyperactivity and lower anxiety, similar to the drug's action in earlier studies on mice.
"Currently there are no therapies on the market to treat cognitive deficits associated with fragile X syndrome. This pilot study [of fenobam] has identified the potential beneficial clinical effects, but further study is needed."
In a third development, scientists in France reported in February having tested a nasal spray containing the hormone oxytocin on 13 patients with "high-functioning" autism – those with normal or above-normal intelligence. Participants who inhaled the hormone were able to interact more easily with others.
"They respond more strongly to others and exhibit more appropriate social behaviour," wrote Elissar Andari, of the Institut des Sciences Cognitives, a French centre for neuroscience research.
Oxytocin is known as the "cuddle chemical", because it is believed to stimulate bonding between mother and baby at birth. Now a second study, led by Evdokia Anagnostou, a child neurologist at Bloorview Research Institute in Toronto, Canada, presented at the Philadelphia meeting last week, found that people with autism given the hormone twice daily for six weeks improved their social functioning. The researchers found they were better at recognising emotions and had a better quality of life than others given a placebo.
Geraldine Dawson, the chief science officer at the US charity Autism Speaks and a psychiatrist at the University of North Carolina at Chapel Hill, said: "For the first time we are seeing drugs that could tackle core autism symptoms."
But Suzi Browne, a spokeswoman for the National Autistic Society in the UK, warned: "While there are recognised links between some forms of autism and fragile X syndrome, there are many other causes of autism, most of which are not yet fully understood.
"As the nature of autism is so complex, many interventions have been tried and tested over the years, but what works for one person won't necessarily work for another. While it is important to further our understanding of the connections between fragile X and autism, further rigorous research is required into any potential intervention, to properly understand and assess the impact that it could have on people's lives."