AUTISM may bring a lifetime of disability and difficulty to the most severely afflicted. As children, they often struggle to communicate, are anxious in situations unproblematic for anyone else and may behave in repetitive ways that disturb others. As adults, they may be shunned—or even ostracised.

Medical science has little to offer. Drugs have limited effects, and although there have been claims for many years that therapies aimed at training a child directly to behave in desirable ways (known as behavioural intervention) can work, the evidence they actually do so is poor. All this, observes Tony Charman, a clinical psychologist at King’s College, London, leaves parents of autistic children vulnerable to false promises. Only this month, for example, a four-year-old boy had to be taken to hospital in Britain after being subjected to a bizarre array of treatments described as “holistic medicine”.

Incidences of such quackery should be reduced by a study published in this week’s Lancet by Dr Charman and his colleagues. The “Pre-school Autism Communication Trial” (PACT) attempted to answer, once and for all, the question of whether behavioural intervention in autism works—and, in particular, whether it does so in the most severe cases. It is the largest such trial yet attempted, and the one with the longest period of follow up. Its answer was: yes, it does. The PACT team found not only that, if carried out correctly, behavioural intervention has an immediate effect, but also that this effect persists. Even six years after therapy, autistic children could communicate better and had a lower level of repetitive behaviour than did a control group of their peers.

The crux of PACT was the nature of the intervention employed. This was designed to train not the children but their parents. The idea was to alter parental behaviour in ways that would then go on to encourage desirable changes in offspring. Specifically, PACT’s intervention trained parents how to communicate with an autistic child. This is rarely a problem with “neurotypical” children, who provide plenty of opportunities for engagement. But autistic children can be difficult to engage with, and their attempts at communication can be so subtle that parents need assistance in detecting them, and advice about how to respond appropriately.

The approach used by PACT involved parents being videoed while playing with their children. Those videos were then replayed to the parents under the tutelage of a speech therapist, who pointed out moments, which might not otherwise have been obvious, when children were attempting to communicate. Even just turning towards a parent may be such an attempt. Having seen when to respond, parents then learned how to do so in the way a therapist would, in order to draw the child out. Parents are thus taught to become therapists themselves.

Family values

This therapy, encouragingly, is neither invasive nor intensive nor costly. It involves sessions once a fortnight for six months, and then a further six sessions, once a month. The results, though not startling, are encouraging. In families who were coached, the percentage of children with severe symptoms (such as having difficulties speaking and learning things) fell from 55% to 46%. In those who formed the control group, and were not so coached, they actually rose—from 50% to 63%.

The study adds to evidence that therapy delivered by parents is helpful for a range of childhood mental-health conditions, including aggression and anxiety. Yet, in the case of autism, some crucial scientific questions remain to be answered. One is whether the age of intervention matters. A second is whether this approach might help less severely afflicted children than those chosen for the study. And a third is whether a similar approach, taught to teachers rather than parents, might permit the method to be extended to schools.

Perhaps the greatest unanswered question, though, is practical. It is how such a therapy might be adopted swiftly and widely. Those involved in the PACT study have already made a start on this. They are creating training materials to be posted on their website, so that therapists who work with autistic children can adapt their methods accordingly. With luck, those methods will spread, and the lives of such children will improve accordingly.