Behavioural interventions to treat anxiety in adults with autism and moderate to severe intellectual disabilities: the BEAMS-ID feasibility study
Authors: Langdon Peter E , Apanasionok Magdalena M , Scripps Emma , Bunning Karen , Filipczuk Malwina , Gillespie David , Hastings Richard P , Jahoda Andrew , McNamara Rachel , Rai Dheeraj , Gray Kylie M 
Published: November 2024

Background
Interventions for anxiety need to be adapted to meet the needs of autistic people with moderate to severe learning disabilities and successfully modelled before evidence about efficacy can be generated from clinical trials.

Objectives
The objectives were to: (1) adapt a behavioural intervention for anxiety, develop an intervention fidelity checklist and logic model, and appraise candidate outcome measures, together with carers, autistic people, and clinicians, (2) characterise treatment-as-usual, (3) model the adapted intervention to determine the acceptability and feasibility for all stakeholders, judge the appropriateness of outcome measures, examine the feasibility and acceptability of consent and associated processes and (4) describe factors that facilitate or challenge intervention delivery.

Design
This study had two phases. Phase 1a: using consensus methods, an intervention adaptation group was formed who met to adapt the intervention, appraise candidate outcome measures, and contribute to the development of the intervention fidelity checklists and logic model. Phase 1b: a national online survey was conducted with professionals to characterise treatment-as-usual. Phase 2: this was a single-group non-randomised feasibility study designed to model the intervention to test intervention feasibility and acceptability, outcome measures, and aspects of the research process.

Setting
Participants were recruited from National Health Service community adult learning disabilities teams in England.

Participants
Participants aged 16 and over with a diagnosis of autism, moderate to severe learning disabilities, an anxiety disorder, and a carer who was available to take part in the intervention. For those who lacked capacity to make a decision about taking part, a consultee had to provide advice that the participant should be included in the study.

Interventions
The intervention comprised 12 sessions alongside treatment-as-usual.

Main outcome measures
The feasibility and acceptability of the intervention and research processes, outcome measure completion rates, and intervention adherence.

Results
The intervention was successfully adapted and modelled with 28 autistic participants with moderate to severe learning disabilities. The intervention was judged to be feasible and acceptable by autistic adults with learning disabilities, carers, and therapists. Carers and therapists suggested minor intervention revisions. Carers completed 100% of outcome measures and the missing data rate was low; however, they indicated that some of the questions were repetitive and said they had difficulty responding to some items. The use of the Mental Capacity Act, 2005, led to an average 5-week delay to participant enrolment. The accrual rate was affected by the COVID-19 pandemic and improved during the summer and early autumn of 2022.

Limitations
Randomisation was not modelled within this feasibility study, although carers and therapists indicated that this would be acceptable.

Conclusions
The BEAMS-ID intervention and associated study processes were judged to be feasible and acceptable. The intervention required minor revision.

Future work
The BEAMS-ID intervention should be tested further within a trial.

Study registration
This study is registered as ISRCTN12637590.

Funding
This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: NIHR129804) and is published in full in Health Technology Assessment; Vol. 28, No. 72. See the NIHR Funding and Awards website for further award information.