A group intervention for parents and carers to recognise and understand restricted and repetitive behaviour in autistic children: a multisite RCT.

Background: Restricted and repetitive behaviours vary greatly between autistic people. Some are a source of pleasure or create opportunities for learning; however, others are functionally impactful and may cause harm. We have developed a parent/carer group intervention (Understanding Repetitive Behaviours), for families of young autistic children, to help parents/carers to recognise, understand and respond to their child's functionally impactful restricted and repetitive behaviours.

Objectives: To evaluate the clinical and cost-effectiveness of the Understanding Repetitive Behaviours intervention.

Design: A clinical and cost-effectiveness, multisite randomised controlled trial of the Understanding Repetitive Behaviours intervention versus a psychoeducation parent/carer group Learning About Autism (n = 250; 125 intervention/125 psychoeducation; ~ 83/site). Analyses completed using intention-to-treat principles.

Setting: Three NHS trusts and universities across England and Scotland.

Participants: Parents/carers aged 18 and over, with an autistic child between 3 and 9 years and 11 months, sufficient spoken and written English, willing to be randomised and attend all group sessions, who agree to maintain their child's current medication up to 24 weeks and not to participate in any other trials up to 24 weeks.

Intervention: An 8-week parent/carer intervention that was delivered face to face and online using a secure digital platform. Randomisation was at the child level using equal allocation ratio.

Information: Research associates and research leads were blind to trial arm allocation.

Main outcome measures: The primary outcome is the Clinical Global Impression - Improvement scale, based on child data. Economic outcomes included incremental cost per additional child achieving at least the target improvement in Clinical Global Impression - Improvement scale, cost consequences and incremental cost per quality-adjusted life-year gained were calculated for the comparison of the Understanding Repetitive Behaviours and Learning About Autism groups.

Results: Two hundred and sixty-two participants were consented and 227 randomised to either the Learning About Autism (113 participants) or the Understanding Repetitive Behaviours (114 participants) arms of the trial. Seventy-two families did not provide data at primary end point. Data were available for 81 Learning About Autism and 74 Understanding Repetitive Behaviours families at 24 weeks. No differences were found between the arms on the Clinical Global Impression - Improvement scale. Analysis of the secondary outcomes indicated that children in the Understanding Repetitive Behaviours arm were more likely to be rated responders in target restricted and repetitive behaviours at 24 weeks. Improvement in parent and family functioning was apparent across both arms over time, with no evidence of differences between the arms. Five serious adverse events were reported, none of which were related to study participation.

Conclusions: The study had a less than expected follow-up at the primary end point and was therefore underpowered. Findings related to the potential clinical effectiveness of Understanding Repetitive Behaviours remain inconclusive. Understanding Repetitive Behaviours is unlikely to be considered cost-effective at 12 months. Future work should determine what the mechanisms of change in functionally impactful restricted and repetitive behaviours are and consider longer time horizons and different methods of valuing benefits for autistic children.

Trial registration: This trial is registered as ISRCTN15550611.

Funding: This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: 16/111/95) and is published in full in Health Technology Assessment; Vol. 29, No. 48. See the NIHR Funding and Awards website for further award information.