The purpose of this pilot intervention trial is to assess the efficacy of newly developed psychoeducation guides designed to manage anxiety in Autism Spectrum Disorder (ASD) by recruiting 30 participants with ASD and high levels of anxiety along with their parent/caregivers who both receive a version of the psychoeducation guide.

ASDs have a devastating impact on adaptive function; current UK lifetime costs of supporting a person with an ASD, along with the opportunity costs of lost productivity, are estimated at £0.8-1.2 million per year (Knapp, Romeo, & Beecham, 2009). The impact of having an anxiety disorder has also been shown to affect an individual's quality of life and functioning over and above physical illness, major depression and socioeconomic factors (Stein et al., 2010). Around 40% of individuals with ASD will also have anxiety symptoms, and treatment for additional mental health problems is also costly. Early work using clinical therapies with individuals with ASD such as modified CBT indicate that the anxious symptoms which co-occur with ASD can be modified and improvements to the anxiety recorded although further work is needed. Therefore, focussing on interventions for individuals with ASD and anxiety may be very beneficial. However, not all individuals with ASD that also present with anxiety will require face to face therapy, therefore, psychoeducation could provide an effective and cost-effective way of improving mental health in ASD through self-help strategies. This could lead to improved outcomes for individuals and less burden on the clinical services supporting these families.

The intervention is focused on psychoeducation. Four psychoeducation guides will be available: parent/caregiver, adult with ASD, adolescent with ASD, and child with ASD. Participants and their parents/caregivers will be give guides to read in their own time over a 4 week period. The guides will be designed to improve participant's and their parent/caregiver's knowledge of anxiety in ASD. The guides introduce the concept of anxiety and how it presents in individuals with ASD, different anxiety triggers, strategies that can be used to manage anxiety, and an introduction to specific anxiety disorders. Level of detail, language and presentation of content will vary across the guides to be appropriate for the functioning level of the readers.

The aim of this study is to recruit 30 participants with autism spectrum disorder (ASD) and high levels of anxiety (aged 8-25 years) and their parent/caregiver into a pilot trial of a psychoeducation intervention. Participants will be recruited through clinical services in South London and the Maudsley (SLaM) and Guy's and St Thomas' (GSTT) NHS trusts through the patient consent to contact register (C4C) in SLaM and via referral from clinical care co-ordinators in the clinics in each trust. Additional participants may be recruited from non-clinical sources such as research recruitment lists held by autism charities or advertisements, including local newsletters, social media sites, emails or letters.

This is a pilot efficacy trial of newly developed psychoeducation guides employing a randomized, parallel-arm, intention to treat design with a 4 week intervention. Participant families will be randomly allocated (1:1) to either an immediate or a delayed start group to allow measurement of anxiety symptoms over a one month period with and without the psychoeducation guide. This design helps to control for the effects of attention (anxiety may show a large placebo response) while allowing all participants access to the intervention.

The aim is to improve participants' and their parent/caregivers' knowledge of the presentation of anxiety in ASD and their confidence in using simple strategies in its management. The primary outcome is improvement of participant and parent/caregiver understanding of the presentation and simple management strategies for anxiety in ASD. Secondary outcomes include improvement in anxiety symptoms and confidence in managing anxiety, feedback on acceptability, usefulness and appropriateness of the guide.

The trial analyses will be intention-to treat. Missing data will be imputed. The primary analysis will compare the groups randomized to immediate vs delayed treatment 4 weeks post randomisation when the immediate start group will have had the guide for 4 weeks and the delayed start group will have been on a "waiting list" for 4 weeks, this controls for attention and spontaneous improvement. The investigators will then check the two groups for comparability at pre-intervention time point (Time 1). If the two groups show similar baselines levels and magnitude of change in knowledge and symptom severity post intervention, they will be combined to gain a further estimate of the treatment effect. Both the knowledge/confidence measure and measure of anxiety symptoms, will be treated as continuous variables. Linear regression models will include baseline severity and randomisation group as predictors. The primary focus will be on parent-carer response but if sample sizes are sufficient, separate, parallel analyses will use data from individuals with ASD.

Inclusion Criteria:

• A diagnosis of ASD.
• Elevated levels of anxiety according to baseline questionnaire measure (Screen for Anxiety Related Disorders; SCARED)
• Have a parent/caregiver who is knowledgeable about participant's mental state and everyday activities and who can facilitate their use of the psychoeducation guide
• Mental age of 8 years or older, the lowest age recommended to complete the standardised measure of anxiety.

Exclusion Criteria:

• Participants or consultees, where relevant, who are unwilling to participate
• Participants who do not have a reasonable level of English. This is because a reasonable level of English will be required to engage with the guide, which is presently written in English and the questionnaires and/or interview questions about the guide. With younger participants with ASD using the materials, English should be the language used at home and school.
• Participants with any significant safeguarding concerns or involvement with court proceedings.
• Participants who are due to commence or have a major change in psychological or pharmacological treatment for their anxiety at a similar time to being given the psychoeducation guide.