Six years later, the parent-coached group still showed reduced symptom severity
Long-term follow-up of the PACT randomised trial
Reviewed by Sian Trombley, CCCFounder, Thrive Family Company
Strong confidence
Source citation
Pickles A., Le Couteur A., Leadbitter K., Salomone E., Cole-Fletcher R., Tobin H., et al. (2016). Parent-mediated social communication therapy for young children with autism (PACT): long-term follow-up of a randomised controlled trial. The Lancet. https://doi.org/10.1016/S0140-6736(16)31229-6
Published 1 January 2016 · Added to Thrive 26 July 2026 · Reviewed 26 July 2026
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Early intervention trials rarely follow families for years. This one did — and the picture at follow-up differed from the picture at endpoint.
Published research findings
The study
Researchers reassessed 121 of the original PACT children roughly six years after treatment ended.
What researchers examined
Whether early parent-mediated therapy produced durable change in autism symptom severity and communication.
What they found
Children in the parent-mediated group showed lower symptom severity and improved parent-child communication at follow-up compared with the control group.
Thrive editorial interpretation
What this may mean for families
Early work with parents may set a slightly different developmental slope, with differences becoming visible over years rather than months.
What this doesn't tell us
Important limitations
Attrition occurred, and follow-up periods included many uncontrolled experiences and supports.
Evidence confidence describes how much weight this study's design can carry — not how strongly the finding applies to any individual child or family.
Therapist perspective — Thrive interpretation, not a finding of the study
Therapist Perspective
It is the best evidence I know that unglamorous, everyday interaction work compounds.
Practical family considerations
Small daily communication changes accumulate over years.
This research summary is educational and does not replace individualized medical, psychological or therapeutic advice.
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Coaching parents in communication changed how parents and children interacted
2010 · Randomized controlled trial
Strong confidence
Why it matters
Parent-mediated therapy is about improving communication and connection, not about reducing autistic traits.