Authors' objectives: 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. To evaluate the clinical and cost-effectiveness of the Understanding Repetitive Behaviours intervention. Restricted, repetitive and stereotyped patterns of interests, behaviours and activities [restricted repetitive behaviour (RRB)] such as repetitive movements, rigid routines, unusual preoccupations, circumscribed interests, resistance to change and sensory sensitivities form one of two key symptom domains required for a diagnosis of autism spectrum disorder (ASD). Frequently, RRBs are reported by autistic people to be enjoyable, functional and helpful. RRBs can be a source of great pleasure. They may provide a basis for friendship and can also build areas of strength, supporting skill development and yielding employment opportunities. For these reasons, and in line with the non-normalising agenda of neurodiversity, the default pathologisation of RRB should be resisted. However, autistic people also report that restricted and repetitive behaviour (RRB) may also be an outward sign of anxiety or distress, and some behaviours can have a functional impact, causing harm to the child or restricting their access to learning or participation in their community. In addition, families can find understanding this repertoire of behaviours particularly difficult, both to understand and in terms of their family impact. Furthermore, RRB can interfere with family functioning and can cultivate negative parenting styles, which in turn may be detrimental to the autistic child’s development. Currently there are no evidence-based interventions available that focus specifically on supporting parents/carers to understand and respond to their child’s functionally impactful RRB. The Understanding Repetitive Behaviour intervention (URB) was developed in collaboration with parents/carers. Understanding Repetitive Behaviours (URB) is an eight-session, parent-mediated group intervention that aims to increase parents/carers’ understanding of their child’s RRB and support them to develop strategies to differentiate between RRB that are beneficial or pleasurable for their child and those that have potential to cause harm (hereby known as functionally impactful RRB), and reduce engagement in these repetitive behaviours. Compare the clinical effectiveness of the URB intervention for NHS community clinical practice with psychoeducation, for the management of functionally impactful RRB in autistic children at 24 and 52 weeks follow-up. Assess the cost-effectiveness and cost consequences of the URB intervention compared with an autism parent/carer psychoeducation group (Learning About Autism; LAA) at 52 weeks follow-up.

Authors' results and conclusions: 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. 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. Fidelity analysis indicated that both URB and LAA were delivered with fidelity to the manual. Five SAEs were reported during the duration of the study, none of which were deemed to be associated with participation. Thirty-one per cent of data were missing at the primary end point. According to the initial sample size calculation for this study, to detect a 20% improvement rate between the URB intervention and LAA group at 24 weeks (proportion of events in the URB 25% and LAA 5%), assuming 10% intra-parent/carer group correlation and equal allocation ratio a minimum of 179 families were estimated to be needed to achieve 80% power (N = 224, 90% power). A post hoc power calculation based on the data available at the primary end point (N = 155) and the same parameters used in the initial sample size calculation indicated 70–75% of the power is retainable. This means that with the available data at 24 weeks, the trial collected less than expected follow-up data and so is unable to answer, with any certainty, whether or not the URB intervention is effective compared to the LAA group. No evidence of a difference was found between the URB and LAA arms for the primary outcome measure (CGI-I) at 24 weeks. Analysis of the secondary outcomes indicates improvement in targeted functionally impactful RRB identified by parents/carers at baseline at 10 and 24, but not 52 weeks and reduction in impact on the family unit for those families who were randomised to the URB arm, but not those who attended the LAA. Improvement in parental functioning (self-efficacy, stress and well-being) and family functioning were apparent across both intervention programmes, with no evidence of differences between the two approaches. Regarding the results of the economic evaluations for the CEA, the incremental cost per additional child achieving the target difference in CGI-I was £36,700 for URB compared with LAA. For the CUA using the imputed data set (n = 199), the incremental cost per QALY for URB compared with LAA is £44,500. At a threshold of £20,000 per QALY there is a 37% chance of URB being considered cost-effective compared to a 63% chance of LAA being considered cost-effective. For the child’s QALYs using the CHU-9D, LAA was both less costly and slightly more effective. Strengths and limitations This is the first large-scale RCT to investigate the clinical and cost-effectiveness of an early intervention for autistic children focusing on functionally impactful RRB – a research priority highlighted by parents of young autistic children. The RCT also used an attentional control, a new development in the evaluation of early interventions in autism. The primary outcome provided a standardised framework of overall functioning rather than simply assessing changes in the specific behaviours targeted using the intervention. Both interventions were delivered by practitioners based in the community rather than in specialist centres and the fidelity of delivery of both interventions was high even taking into account the changes necessitated by the COVID-19 pandemic. Unfortunately, probably at least in part due to the COVID-19 pandemic, the relatively high attrition rate at 24 weeks meant that the study collected less than expected data at the primary end point. We are also aware that there are other potential factors that may have contributed to our lack of difference between the URB and LAA parent groups.

Authors' methods: 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. Three NHS trusts and universities across England and Scotland. 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. 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. The study was a clinical and cost-effectiveness, large-scale, multisite randomised controlled trial (RCT) of the URB parent group intervention versus the LAA psychoeducation parent group (current best practice) for parents of autistic children aged 3 years to 9 years 11 months. All analyses were done under an intention-to-treat principle. The primary outcome was at 24 weeks. The economic evaluation was conducted from the perspective of both NHS costs and family access to local community services. Parents and carers aged 18 years and older were eligible for study entry if their child met the following criteria: Aged 3 to 9 years 11 months at the time of consent with a clinical diagnosis of autism spectrum disorder (ASD), across a range of functioning levels and abilities (verbal and nonverbal). Parents/carers with sufficient spoken and written English to provide written informed consent and complete the assessments, including being able to identify one or more functionally impactful RRB and participate in the group-based programme. Parents/carers were willing to be randomised and attend all the group sessions for the allocated arm of the study and agree to maintain their child’s current medication regime up to 24 weeks (unless change is advised by the child’s clinician) and agree not to participate in any other trials while involved in the trial up to 24 weeks. Parents/carers were not eligible for study entry if their child met any of the following criteria: no clinical diagnosis of autism or ASD; no functionally impactful RRB could be identified; currently taking part in another parent group-based programme trial; had a sibling already taking part in this study; parents/carers had a severe learning disability or a significant mental health disorder that would interfere with their ability to take part in a group-based programme.

Project Status: Completed

URL for project: https://www.journalslibrary.nihr.ac.uk/programmes/hta/16/111/95

Year Published: 2025

URL for published report: https://www.journalslibrary.nihr.ac.uk/hta/WHTU0367

URL for additional information: English

English language abstract: An English language summary is available

Publication Type: Full HTA

Country: England, United Kingdom

DOI: 10.3310/WHTU0367

Organisation Name: NIHR Health Technology Assessment programme

Contact Address: NIHR Journals Library, National Institute for Health and Care Research, Evaluation, Trials and Studies Coordinating Centre, Alpha House, University of Southampton Science Park, Southampton SO16 7NS, UK

Contact Name: journals.library@nihr.ac.uk

Contact Email: journals.library@nihr.ac.uk