The Effect of Korean Version of PEERS Social Skills Training for Young Adults (PEERS-YA-K) With Autism Spectrum Disorder
Phase: NA
Conditions: Autism Spectrum Disorder, Autism
Sponsor: Seoul National University Hospital

 
A randomized controlled trial of the Korean version of the Program for 
the Education and Enrichment of Relational Skills for Young Adults 
(PEERS®-YA-K) with autism spectrum disorder 
 
 
ClinicalTrials.gov identifier: NCT03310775 
 
 
Study protocol and statistical analysis plan 
 
 
 
 
 
 
 
Update date: 09/06/2020 
 
 
 
 
 

Recruitment of participants 
The participants were recruited from the Child and Adolescent Psychiatric Clinic at 
Seoul National University Bundang Hospital, through advertisements at the Smile Together 
Foundation (a local advocacy institute of ASD), a community of child and adolescent 
psychiatrists, an internet group of families of youth with ASD, and a website for Seongnam 
Child and Adolescent Psychiatry Mental Health Care Center. Inclusion criteria for young adults 
included: (1) between 18 and 35 years of age, (2) graduated from high school or expected to 
graduate by the time the intervention starts, (3) experiencing social difficulties as recognized 
by young adults and/or social coaches, (4) previously diagnosed with or possibly having a 
diagnosis of ASD, (5) verbally fluent, (6) full scale intelligence quotient (FSIQ) ≥ 70 by 
standardized intelligence test, and (7) substantially motivated to participate to intervention. 
Exclusion criteria included: (1) history of major mental illness (e.g., schizophrenia, bipolar 
disorder, psychosis, and risk of self-mutilation), (2) significant physical disabilities including 
visual and/or hearing impairments, (3) clinically significant neurological or physical disease 
that would preclude participation in group-based social activities, and (4) difficulties for 
parents to understand and cooperate with the intervention. 
The study was approved by IRB of Seoul National University Bundang Hospital (IRB 
no. B-1611/371-303). Written informed consent was completed by all young adults and social 
coaches who participated in the present study.  
 
Screening and randomization process  
Participants were screened for eligibility by telephone interview using the Phone 
Screening Interview in the PEERS®-YA treatment manual. Motivation, social problems related 
to friendships, willingness to follow the rules in the group, comorbidities, and inclusion and 
exclusion criteria were discussed during the telephone interview. 

Diagnosis of ASD was confirmed for screened individuals by two board-certified child 
psychiatrists based on diagnostic criteria of the fifth edition of the Diagnostic and Statistical 
Manual of Mental Disorders. The Autism Diagnostic Observation Schedule (ADOS; Lord et 
al. 2008) and the Autism Diagnostic Interview-Revised (ADI-R; Lord et al. 1994) were used 
for supporting diagnostic procedures and administered and scored by a special educator trained 
and certified for these instruments (GYB). IQ was assessed using the Korean Wechsler Adult 
Intelligence Scale-IV (K-WAIS-IV; Hwang et al. 2012) and assessment of adaptive functioning 
was conducted using the Korean version of the Vineland Adaptive Behavior Scale-II (K-VABS-
II; Volkmar 2013, Hwang, Kim & Hong 2014). Subjects meeting eligibility criteria were 
randomly assigned to a treatment group (TG) or waitlist control group (CG) using randomized 
block design. We divided each group into two separate treatment groups of approximately 9–
10 young adults.  
 
Subjects 
Forty-eight young adults ranging from 18 to 35 years old and their social coaches were 
recruited for the RCT. Ten participants were excluded during the randomization procedure; six 
were not adequately motivated, one did not meet the diagnosis of ASD, one had difficulty 
understanding self-report scales, one had a problem with school, and one had to fulfill a military 
commitment. A total of 38 participants were screened, but one participant refused to be 
randomized to the CG. As a result, 37 participants were randomized; 19 were assigned to TG 
and 18 to CG.  
 
Treatment intervention  
The PEERS®-YA consisted of 16 weekly 90-minute sessions. Social coaches and the 
young adults were given concurrent sessions in separate rooms and each session was led by 

five trained treatment leaders. One of the trained treatment leaders (HJY) was a PEERS® 
Certified Provider for both PEERS® for Adolescents and PEERS®-YA, and another group 
leader was certified for PEERS® for Adolescents (JHK). Both received 20 hours of 
comprehensive training through the UCLA PEERS® Clinic by the program developer for each 
program. The social coach group leaders were board-certified child psychiatrists and special 
educators with specialty training in the treatment of ASD and group therapy; the young adult 
group leaders were licensed clinical psychologists and graduate-level trainees in clinical 
psychology. The behavioral coaches were clinical psychology trainees and psychology 
graduate students with experience working with children and adolescents with ASD and other 
developmental disorders. All members of the treatment team were trained and supervised by 
PEERS® Certified Providers for the duration of the intervention.   
The treatment leaders translated the Korean version of the PEERS®-YA Treatment 
Manual together and had regular meetings (once every week for four months) until the 
translation was completed. In addition to the treatment sessions, the Social Coaching Handouts 
and the appendices of the original PEERS®-YA Treatment Manual were translated into Korean, 
including the Planned Absence Sheet, Phone Roster, In-group Call Assignment log, and 
Homework Compliance Sheets, the latter of which was used to rate treatment adherence.  
After the translation was completed, the PEERS®-YA Certified Provider conducted a 
24-hour training workshop on the implementation of the treatment sessions. As part of this 
training, treatment leaders observed each session of the treatment conducted in Korean by the 
PEERS®-YA Certified Provider and then established reliability with the treatment protocol 
before conducting sessions with participants.  
The behavioral coaches, who provided support to the group leaders, were fully trained 
and supervised by a young adult group leader in all content and intervention processes, and 
attended weekly case conference meetings. Behavioral coaches conducted role-play 

demonstrations of targeted skills, provided social coaching with performance feedback during 
behavioral rehearsal exercises, and monitored treatment fidelity and homework compliance 
throughout the sessions. 
The didactic lessons focused on the social skills necessary for developing and 
maintaining friendships, romantic relationships, and managing peer conflict and rejection. The 
lessons included conversational skills, electronic forms of communication, developing 
friendship networks and finding sources of friends, appropriate use of humor, peer entry and 
exiting strategies, organizing and having successful get-togethers with friends, handling teasing 
and chronic bullying in the school or workplace, managing peer pressure, conflict resolution, 
strategies related to dating etiquette, showing romantic interest, asking someone on a date, 
going on dates, and general dating guidelines. The detailed processes and characteristics of the 
PEERS®-YA intervention are described by Laugeson (2017).  
Within the young adult group, each session included a homework review and didactic 
lesson including a role-play demonstration of targeted behaviors. Appropriate and 
inappropriate examples of social etiquette were demonstrated by the behavioral coaches. 
Didactic lessons were followed by behavioral rehearsal exercises in which young adults 
practiced the appropriate newly learned skills while receiving performance feedback from the 
treatment team.  
Within the social coach group, homework was reviewed and discussed for two-thirds 
of the session and homework compliance and quality were recorded. During the review, 
specific instructions on how to provide assistance and social coaching to the young adults 
outside of the treatment setting were provided. After homework review and discussion, the 
social coaches received didactic instruction regarding the targeted social skill being highlighted 
in the young adult group. Social Coaching Handouts were also distributed, which provided an 
outline of the rules and steps of the lesson, as well as a summary of upcoming homework 

assignments.  
The last ten minutes of every 90-minute group included a reunification between young 
adults and social coaches in which the rules and steps of the targeted skills were highlighted, 
and homework assignments were given to young adults and social coaches. Research staff 
monitored treatment fidelity directly from the treatment manual in every session in order to 
maintain the integrity of the program and ensure that all material was covered.  
 
Measures 
Every participant and their social coach in the TG completed outcome measures prior 
to the start (test 1) and after the completion of the intervention (test 2). Participants and social 
coaches in the CG completed outcome measures upon entering the study (test 1), prior to the 
start of treatment (test 2), and after the completion of the treatment (test 3). Four months after 
completing the program, both groups completed outcome measures to evaluate the 
maintenance of the treatment effects (TG: test 3; CG: test 4). Assessment schedules for both 
groups are shown in Figure 1. Social skills training was prohibited for the CG during the 
waiting period, but medication and general follow-up visits for counseling were allowed. 
 
Primary measures 
1. Autism Diagnostic Observation Schedule, second edition (ADOS-2 Module 4; Lord et 
al. 2012) 
The ADOS-2 is a standardized test designed to diagnose individuals with ASD by 
observing their communication and social behaviors during semi-structured play and/or an 
interview. The ADOS-2 is composed of four modules. Each module is selected according to 
the expressed language level and chronological age of participants and requires 35 to 40 
minutes to administer. The current study used ADOS-2 module 4. Module 4 of the ADOS-2 is 

used to diagnose adolescents and adults who are verbally fluent. It is scored on five domains: 
language and communication, reciprocal social interaction, imagination, stereotyped behaviors, 
restricted interests, and other abnormal behaviors. In this study, raters on ADOS-2 examined 
participants blinded to the group of participants and also for pre-treatment or post-treatment. 
 
2. Test of Young Adult Social Skills Knowledge (TYASSK; Laugeson 2017) 
The TYASSK is 30-item criterion-based measure developed for use with the PEERS®-YA 
intervention. The TYASSK is used to evaluate the change in young adults’ knowledge of 
specific social skills taught during the intervention period, with two items derived from each 
of the lessons. The TYASSK is based on the Test of Adolescent Social Skills Knowledge. The 
test requires approximately 5 minutes to complete and includes buzzwords related to the 
didactic lessons. Young adults who participated in this study were asked to select the most 
fitting of the two possible answers. Scores range from 0 to 30, with higher scores reflecting 
more knowledge of social skills. The English version of the TYASSK was translated into 
Korean with the author’s permission, and then back-translated into English by a bilingual 
translator unrelated to this study.  
 
3. Korean Version of the Social Skills Rating System (K-SSRS; Elliott & Gresham 1991, 
Moon 2003) 
The SSRS is a multi-rater feedback questionnaire (teacher, parents, and student forms) to 
assess social skills, problematic behaviors and academic competence (in the Teacher report 
form) and it consists of three forms for: pre-school, elementary, and secondary students. The 
SSRS for secondary students, originally developed for adolescents, has been proven to be 
appropriate for use in evaluating the social skills of adults with high functioning ASD. It was 
modified for college students (K-SSRS: college level) and its reliability and utility were 

verified by Moon (2003). The K-SSRS consists of 27 items which are rated on a Likert scale 
from 1 (“not at all”) to 7 (“almost always”).  
 
4. Social Responsiveness Scale-2 (SRS-2; Constantino & Gruber 2012) 
The SRS-2 is a 65-item scale used to screen children at risk for ASD and consists of 
measures regarding the child’s social interactions, communication, and stereotyped behaviors. 
Individual items are rated on a Likert scale from 1 (“not at all”) to 4 (“almost always”) to 
measure the severity of ASD symptoms as they occur in natural social settings. The SRS-2 
consists of four forms: preschool (ages 2.5-4.5 years), school-age (ages 4-18 years), adult (ages 
19 years and older), and an adult self-report. The individual is classified as being at a high risk 
of ASD when the score is greater than 75. In this study, we used the adult form reported by the 
caregiver and the self-report form.  
 
Secondary measure 
1. Korean version of the Vineland Adaptive Behavior Scale, second edition (K-VABS; 
Volkmar 2013, Hwang, Kim, & Hong 2014) 
The K-VABS is an interviewed survey and measures adaptive behaviors of individuals 
such as personal and social skills, used for everyday living from birth to age 90. These are 
based on the reports of primary caregivers and teachers. The K-VABS contains 5 domains each 
with 2-3 subdomains. The main domains are: Communication, Daily Living Skills, 
Socialization, Motor Skills, and Maladaptive Behavior (optional). Behaviors are rated on a 0 
(a skill that is not used by the individual) – 2 (a skill used most of the time) rating scale. The 
current study used only the communication, daily living skills, and socialization domains.  
 
2. Beck Depression Inventory (BDI; Beck, Steer, & Garbin 1988, Han et al 1986) 

The BDI is a 21-question, self-report inventory, rated from 0 to 3 in terms of intensity. The 
items are used to assess the intensity of 21 depression-related symptoms and attitudes such as 
hopelessness and irritability, cognitions such as guilt or feelings of being punished, fatigue, 
weight loss, and lack of interest in sex. The current study used the BDI-II published in 1996 
which was designed for individuals ages 13 and over. The maximum score of the BDI is 63 
points, with a suggested interpretation of: minimal range = 0–13, mild depression = 14–19, 
moderate depression = 20–28, and severe depression = 29–63.  
 
Statistical analyses 
Baseline characteristics were compared between the TG and DTG with independent 
samples t-tests for continuous variables and Fisher’s Exact Test for categorical variables. 
Changes in outcomes between baseline and post-intervention were examined with paired t-tests 
and also the maintenance of treatment effects in both groups. Post-intervention follow-up 
measurements were analyzed using repeated measures analysis of variance (ANOVA) 
comparing both between-group and between-time differences in outcomes with groups by a 
measured time point interaction. The significance of difference was interpreted with treatment 
x time interaction from the analysis, and the treatment effect size was assessed with Cohen’s d 
for the interaction (Morris, 2008). All statistical analyses were conducted using SAS version 
9.4 (SAS Institute, Cary, NC, USA) and statistical signiﬁcance was deﬁned as p < 0.05.