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A parent-focused therapy for young children with autism continues to have beneficial effects on symptoms and communication almost six years after the end of treatment.

This UK randomised controlled trial investigated the effects of a one-year social communication therapy in 152 UK children aged two to four years with severe autism. The therapy, partly delivered by parents, aimed to help them adapt their style of interacting with their child.

Children who received the intervention had less severe symptoms at the end of the initial one-year intervention period than those who received treatment as usual. When these children were followed up nearly six years later at age seven to 11 years, children who had received the intervention still had less severe symptoms than those who had received usual care. When all the data from both time points were combined, the intervention had a statistically significant overall beneficial effect.

This therapy, which is less intensive than some existing approaches, may be an option for young children with autism, although the cost effectiveness is not known.

Why was this study needed?

Autism is a severe, lifelong neurodevelopmental disorder that affects social interaction, communication, interests and behaviour. Diagnosis is often made by the age of three to four years. A diagnosis of autism can be devastating for children with autism and their families, because of the difficulties of communicating with the child and their behavioural and care needs.

An estimated 1% of children and young people in the UK have autism. Severely affected children also have long-term care needs. The cost of supporting these children in their health and education needs is estimated at £2.7 billion a year.

Autism can be managed with psychosocial therapies that aim to improve the child’s skills in communication, social interaction, imaginative play and academic learning. Some types of intervention can involve hours of intensive work, which can have a practical, emotional and financial impact on families.

Parent-focused psychosocial therapies appear to reduce symptom severity in children with autism. The therapy tested in the first trial by these researchers was a relatively low intensive intervention and showed a benefit. These researchers wanted to follow up participants to clarify whether these approaches can have a long-term effect on autism.

What did this study do?

The Preschool Autism Communication Trial (PACT) investigated the effects of a parent-focused social communication therapy on young children with autism.

This randomised controlled trial recruited 152 children aged two to four years with severe autism from three centres in the UK. Children and their parents were randomly assigned to receive the PACT intervention on top of treatment as usual or treatment as usual alone.

The PACT intervention aims to increase parent sensitivity and responsiveness to child communication. The intervention comprised six months of clinical sessions with parent training every two weeks, followed by six months of sessions once a month. Parents did 20 to 30 minutes of practice activities with their child every day and both symptoms and communication were measured on recognised scoring scales.

Children were initially followed up at the end of the one-year intervention period. A total of 121 (80%) participants were followed up again nearly six years later.

What did it find?

  • At the end of the intervention period, children in the intervention group had less severe symptoms than those in the control group. Those in the intervention group scored on average 6.7 out of 10 on the comparative severity score (CSS) subscale of the Autism Diagnostic Observation Schedule (ADOS), whereas those in the usual care group scored 7.3 out of 10 (effect size [ES] 0.64, 95% confidence interval [CI] 0.07 to 1.20).
  • At long-term follow-up, children in the intervention group still had less severe symptoms (ADOS CSS 7.3 ) than those in the control group (ADOS CSS 7.8) but this difference was not statistically significant (ES 0.70, 95% CI ‑0.05 to 1.47).
  • When all the data for the entire study period were assessed together, children in the intervention group had less severe symptoms than those in the control group (ES 0.55, 95% CI 0.14 to 0.91). At follow-up, the proportion of children who had severe symptoms (ADOS CSS 8-10) was lower in the intervention group (46%) than in the control group (63%).
  • Parent-child communication, measured using the Dyadic Communication Measure for Autism (DCMA), was better in the intervention group when all data were analysed together (ES 0.33, 95% CI 0.11 to 0.57), but not when data from the long-term follow-up were considered on their own (ES 0.29, 95% CI ‑0.02 to 0.57).
  • Other outcomes, such as those related to adaptive behaviour and prosocial behaviour, were not significantly better in the intervention group.

What does current guidance say on this issue?

The NICE guideline on autism spectrum disorder in under 19s: support and management (2013) recommends considering specific social communication interventions for the core features of autism in children and young people.

These interventions should include play-based strategies with parents, carers and teachers to increase joint attention, engagement and reciprocal communication in the child or young person. Strategies should aim to increase the parents’, carers’, teachers’ or peers’ understanding of, and sensitivity and responsiveness to, the child or young person's patterns of communication and interaction.

What are the implications?

The long-term effects of the intervention in this study were modest, but any sustained improvement after the intervention ends is valuable in children with severe autism and might be attributed to the techniques learnt by parents or the improved interaction. The results indicate that healthcare professionals should consider early psychosocial therapy in young children with autism, in line with NICE guidance.

The trial looked at an early intervention in young children with severe autism, so this approach may have different effects in children who have less severe autism.

The intervention was relatively low intensity compared with existing treatments, so could potentially be cheaper. However, the trial doesn’t consider the cost effectiveness of the intervention, and there will be costs in training therapists too.


Citation and Funding

Pickles A, Le Couteur A, Leadbitter K, et al. Parent-mediated social communication therapy for young children with autism (PACT): long-term follow-up of a randomised controlled trial. Lancet. 2016;388(10059):2501-09.

This study was sponsored by the University of Manchester. The study was principally funded by the Medical Research Council (MR/K005863/1), with additional funding from the UK Department of Health and the National Institute for Health Research (NIHR) Biomedical Research Centre at South London and Maudsley NHS Foundation Trust and King’s College London.



Green J, Charman T, McConachie H, et al. Parent-mediated communication-focused treatment in children with autism (PACT): a randomised controlled trial. Lancet. 2010;375(9732):2152-60.

NHS Choices. Autism spectrum disorder (ASD). London: Department of Health; 2016.

NICE. Autism spectrum disorder in under 19s: support and management. CG170. London: National Institute for Health and Care Excellence; 2013.

Sigafoose J, Waddington H. 6 year follow-up supports early autism intervention. Lancet. 2016;388(10059):2454-55.

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The comparative severity score (CSS) of the Autism Diagnostic Observation Schedule (ADOS) rates severity of autism symptoms. Scores range from 1 to 10, where 1 represents no evidence of autism and 10 represents very severe autism.

The Dyadic Communication Measure for Autism (DCMA) assesses parent-child communication during naturalistic play. It measures when the child initiates communication with the parent, when the parent responds to the child, and conversational turns between parent and child.


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