KONTAKT Australia a Social Skills Group Training for Adolescents on the Autism Spectrum

The parents will fill this questionnaire (Parent form). This is a 27-item measure assessing emotion regulation and competency in social skills.The questionnaire is designed to measure frequencies of effective engagement in social behaviours (e.g. "chooses appropriate solutions to social problems" or "deals effectively with bullying"), examining the competency of these skills. Responses are rated on a 5-point Likert scale, ranging from "never (0)" to "always (4)", yielding a total score of 0-108, with higher scores indicating higher competencies in social behaviour.

The adolescents will fill this questionnaire. Emotions are displayed in the form of 2-5 second silent coloured video clips, with 4 multiple choice options one of which is the correct emotion label and 3 are distractor items. The distracter options were randomly selected from the entire Mind reading battery emotion groups, excluding the emotion group the target stimuli originates from. Further details of the stimuli are outlined in table 4. During the presentation of stimuli, eye tracking data will be recorded via a Remote Eye Tracker Device (RED) developed by SensoMotoric Instruments, enabling examination of fixation patterns and fixation durations.

The adolescents will fill this questionnaire. It measures an individual's confidence in regard to their ability to successfully perform behaviours associated with each facet of the interpersonal Circumplex (Assert, Distance, Yield, and Connect). Each octant scale shows a progressive blend of two axial dimensions (e.g. "speak up" representing an assertive action, "get them to leave me alone" a distancing action, and "tell them when I am annoyed" combining these two actions).

The adolescents and parents (parent proxy) both will fill this questionnaire. It is a 23-item parent proxy report and an adolescent self-report measure of adolescent's quality of life underpinned by the four subscales of physical, emotional, social, and school functioning. Responders rate items according to if they have been a problem for them on a 5-point Likert scale ranging from "never (0)" to "almost always (5)", with lower scores indicating better quality of life.

The adolescents will fill this questionnaire. This is a self-report measure consisting of 24 statements such as ''I feel left out of things at school'', or ''I get along with my classmates'', measuring four dimensions of loneliness in young people (isolation, friendship and positive and negative attitudes toward solitude).

The adolescents will fill this questionnaire. The NEQ is a 32-item questionnaire requiring adolescents to quantify, on 5-point Likert scale with response options ranging from "Not at all" to "Extremely", any negative events experienced during the intervention period, asking participants to attribute their causality to either the program or external circumstances

The adolescents will fill this questionnaire. This is a 9-dimension Health related quality of life scale (worried, sad, pain, tired, annoyed, school work, sleep, daily routines and activities), designed to estimate the adolescent's Quality adjusted life years (QALY), providing a standardized measure of disease burden. The measure is rated on a 5-point scale with a "don't" sentence linked with no problems (e.g. I don't feel sad today) and "very" with the participant experiencing a lot of problems (e.g. I feel very sad). Calculation of an universal score is supported by an adolescent specific scoring algorithm, with 1 representing 'full health' and 0 'death'.

The adolescents and parents (parent proxy) will fill this questionnaire. This 5-item measure, specifically designed for the purposes of this study, asks "In the last 24 hours, on a scale of 1 to 10 I have been feeling …" with answers rated on a 10-point scale regarding five dichotomised emotional sets (sad/happy, lonely/unlonely, angry/calm, scared/unafraid, and anxious/confident).

The adolescents will fill this questionnaire. This is a 20-item measure assessing adolescents' self-reported anxiety in social situations, via items such as "I become tense if I have to talk about myself" or "I find it easy to make friends my own age". Items are rated on a 5-point scale ranging from "Not at all" to "extremely". Total scores range from 0 to 80 with higher scores indicating greater anxiety in social situations

The parents will fill this questionnaire (Parent form). This will be measured via a tailored version of the Trimbos/iMTA questionnaire for patients with a psychiatric disorder (TiC-P), a well-established questionnaire examining health care usage as well as any work, education and productivity losses incurred by participants and their carers. The modified version of the TIC-P employed in this study comprise six sections enquiring about health care visits, support received both at and outside of school, medications and supplements, work, and education and productivity losses incurred by both parents and adolescents.

This will be assessed by a blinded assessor

The adolescents and parents both will fill this questionnaire. This is a short 6-item parent and adolescents self-report instrument, measuring satisfaction with group attendance. Each item is scored on a 4-point Likert scale with response options ranging from "Yes, very much" to "No" with an open comment section, encouraging participants to freely share their experiences with the intervention.

This measure will be used as the parent's primary outcome.The Social Responsiveness Scale - Second Edition (SRS-2) School-Age Form is a 65-item rating scale, designed to measure social deficits in individuals with ASD via parent proxy report has been used as the primary outcome in a previous study evaluating KONTAKT and has been used as the basis for the power calculation for the present RCT.