Feasibility and acceptability of autism adapted safety plans: an external pilot randomised controlled trial.

Background: Autistic people are a high-risk group for self-harm and suicide. There are no evidence-based suicide prevention interventions developed specifically for autistic people. We undertook a pilot feasibility randomised controlled trial of autism adapted safety plans (AASP) to reduce self-harm and suicide for autistic people. Methods: This study took place in the United Kingdom and followed a randomised, two-arm, controlled design. Autistic adults (n = 53, mean age = 39, gender = 49% female, 29% not male or female) were recruited via third sector organisations and self-referral between 11.8.21 and 19.10.22. Participants were randomised without stratification to usual care with or without AASP. The AASP was completed by the autistic adults together with someone trained to support them. Research staff who completed follow-up assessments were blind to participant allocation. Primary outcomes were feasibility and acceptability. Participants were assessed at baseline, 1 and 6 months. Primary data were analysed under the intention to treat principle. Study protocol is published. The trial is closed to new participants. This study is registered with the ISRCTN registry, ISRCTN70594445. Findings: 53 participants consented, 49 were randomised to either AASP with usual care (n = 25) or usual care (n = 24). 68% of participants in the AASP arm were satisfied with the AASP and 41% rated it as useable. Feedback on the AASP and research methods were positive with suggested adaptations to some outcome measures. Retention and completion of outcomes measures in both arms was excellent, as was fidelity of delivery of the AASP. Interpretation: Study progression criteria were met, suggesting that the parameters of a future definitive trial of clinical and cost effectiveness of AASP to reduce self-harm and suicide in autistic adults are achievable, with minor recommended adaptions to outcome measures and AASP. Future research should explore the use of AASP in routine clinical practice. Funding: This study is funded by the NIHR [Public Health Research Programme (NIHR129196)].