Title: Improving the Accuracy and Efficiency of Autism Assessment for Adults
Funder: Department of Health and Social Care

Abstract: Background Autism spectrum disorder (henceforth autism ) is a lifelong neurodevelopmental condition characterised by social, communication, flexibility and sensory difficulties. There are over 560,000 autistic adults in the UK. Most have not received an autism diagnosis. This prevents them receiving appropriately-targeted support, contributing to poor mental and physical health. Improving autism care is one of NHS England s top priorities over the next 10 years1. Ongoing efforts to ensure that autistic adults are identified and helped are constrained by a lack of accurate and time-efficient diagnostic tests for adult autism. NICE guidelines state that an autism diagnostic assessment should include informant reports, i.e., information from someone who knows the person well, ideally since birth. Currently, well-evidenced, informant-report diagnostic interviews for adult autism are lacking. To fill this gap, we recently developed such an interview, called the 3Di-Adult, that asks about current and past behaviour. We published preliminary evidence that the 3Di-Adult takes under 60 minutes to use, and is reliable and accurate at detecting autism2. Before it can be adopted across the NHS, a more rigorous evaluation is required. One challenge for adult autism assessment is that many patients do not have someone who knew them since birth to provide information, e.g., because their parents have passed away. To address this, we also created the 3Di-Adult-Current. This version of the interview only asks the 3Di-Adult questions about current (as opposed to past) behaviours. The 3Di-Adult-Current can be administered to an informant who knows the person well now (e.g., friend, spouse, carer), but who did not know them in childhood. Objectives Primary objective: To test the reliability and diagnostic accuracy of the 3Di-Adult and 3Di-Adult-Current with respect to a gold-standard autism diagnosis, for men and women. Secondary objectives: (i) To make final adjustments to the 3Di-Adult and 3Di-Adult-Current, maximising useability; (ii) To enhance the training course for the 3Di-Adult and 3Di-Adult-Current. Methods Participants will be 204 consecutive referrals (102 men, 102 women) to 5 NHS adult autism assessment services. For each participant: (i) the 3Di-Adult will be administered to an informant who has known them since childhood; and (ii) the 3Di-Adult-Current will be administered to an informant who knows them now but did not know them in childhood. For a subset of participants (n=52) these interviews will be re-administered 8 weeks later, to measure test-retest reliability. Diagnostic accuracy (sensitivity and specificity) of the 3Di-Adult and 3Di-Adult-Current will be evaluated in relation to a gold-standard autism diagnosis, which will be entirely independent of information collected in the 3Di. Timeline The project will last 24 months. Impact and dissemination This research can have an immediate impact on the accuracy and efficiency of NHS adult autism diagnostic services, potentially helping the hundreds of thousands of UK autistic adults who are currently undiagnosed. It can also reduce the cost of adult autism assessment, as the interviews are cheaper to administer than widely-used alternatives. Our dissemination plan includes a free-to-attend national conference, and the proactive sharing of findings via the team s extensive academic, clinical, media and governmental networks.

Lay abstract: This project will test the accuracy and usability of 2 new diagnostic interviews for assessing adult autism in a time-efficient manner. The research can produce immediate and widespread benefits for adults who suspect they have autism, and for those who commission and run NHS adult autism and mental health services. There are over 560,000 autistic adults in the UK, and most of these are currently undiagnosed. These overlooked autistic adults are often misunderstood and marginalised, commonly experiencing mental health problems and socio-economic disadvantage. There is an urgent need to identify this lost generation of autistic adults, so they can receive targeted support. Ongoing efforts to improve recognition of adult autism are hampered by a current lack of quick and accurate diagnostic tools. NHS guidelines for high-quality care (NICE Guidelines) state that an autism assessment should include informant reports , i.e., information from someone who knows well the person being assessed. But, currently, there is no evidence-based, informant-report interview that was designed for assessing autism in adults. The 3Di-Adult was designed to fill this gap. It is a new informant-report diagnostic interview that collects information on current and past behaviour. We have also developed a version of the 3Di-Adult that only asks about current behaviour, called the 3Di-Adult-Current. This is for when adults seek autism assessment, but do not have an informant who knew them in childhood. We recently published a study providing initial evidence that the 3Di-Adult is a quick and accurate diagnostic interview2. Also, data from this study suggest the 3Di-Adult-Current works well. But before they can be adopted across the NHS, the 3Di-Adult and 3Di-Adult-Current must be tested more thoroughly. To accomplish this, we have drawn together an expert team of autism researchers, clinicians and autistic adults. We will evaluate the accuracy of the 3Di-Adult and 3Di-Adult-Current at detecting autism amongst 204 patients (102 women, 102 men) seeking assessment from NHS adult autism services in Bristol, London, Bedfordshire and Cambridge. The project can immediately improve NHS practice, via the widespread adoption of the 3Di-Adult and 3Di-Adult-Current by autism services. To facilitate this, the project includes work to enhance 3Di training. This project s overall aim, which is to improve recognition of adult autism, was identified by the autism community as a top priority for research, via an extensive consultation exercise run by the James Lind Alliance3. One co-applicant is an autistic adult, and this proposal has been reviewed by another autistic adult. The research has been shaped by consultations with autistic adults and clinicians. We have planned and budgeted for further input from these groups at every stage of the project, so we can use patient and public perspectives to ensure the research delivers maximum benefit for autistic people.

Research activity codes: 4.2 EVALUATION OF MARKERS AND TECHNOLOGIES
Health categories: MENTAL HEALTH