This study is designed to evaluate a preventive intervention program designed to support families (parents and typically developing adolescent siblings) that include a child with an intellectual and/or developmental disability. Participant families will be randomly assigned to either the treatment condition, in which they will receive psychoeducation and communication coaching over a four-week period, or the control condition, in which they will receive self-study materials. All subjects will participate in a pre-test assessment and three post-test assessments over the course of the year.

A critical need exists for an evidence-based program to ameliorate the impact of family stress and conflict on the overall well-being of parents and TD siblings, as well as individuals with IDD. Our objective in this study is to test the efficacy for parents, TD siblings, and children with IDD of an adaptation of the psycho-educational and communication training approach used in a previously validated prevention/intervention program for community families, and to examine the mechanisms associated with change processes that occur as a result of the 4-week program. Our long-term goal is to increase the availability and affordability of empirically-supported family-systems approaches to reduce family stress and conflict in families of individuals with IDD. Our central hypothesis is that participation in the program will support the identified needs of families with a child with IDD, improve the well-being and adjustment of parents, increase emotional security and adjustment for TD siblings, and be associated with improvements in adaptive functioning for individuals with IDD. This central hypothesis is supported by promising qualitative evidence and preliminary analyses from an ongoing pilot study using the adapted curriculum included in the present proposal. Our rationale is that providing a family-systems approach to improving the family environment will support the well-being of each family member, including the child with IDD. The specific aims are: (1) determining the efficacy of the program for parents, (2a) determining the efficacy of the program for typically developing siblings, (2b) testing process models, guided by the Emotional Security Theory (EST; Davies & Cummings, 1994), to explain how and why and for whom and when changes occur as a result of the program, and (3) examining the impact of the program on individuals with IDD. Families (n=150) that include a child with IDD and a TD sibling between 11 and 17 years of age, will be randomly assigned to one of two groups: (1) parent and typically developing sibling intervention, or (2) resource only control. Multi-method assessments of all family members will be obtained at pre- and post-intervention visits, and 6-month and 1-year follow-ups. The approach is innovative because it addresses multiple family members' needs, tests theory about explanatory models for program impact, and utilizes a brief, psycho-educational format and a RCT design to evaluate its efficacy. This research is significant because it will create an inexpensive model program for family-system-level interventions for families of children with IDD, benefiting parents, siblings and the child with IDD, including evaluations of program effectiveness in standing community centers.

Inclusion Criteria:

• Participants in all conditions will include mothers, fathers, TD siblings between 11 and 17 years old, and individuals with IDD of any age.
• Participants must be able to understand and respond to survey questions in English
• Parents must be cohabitating, with both participating children living in their home.
• Individual with IDD falls into one or more of the following categories: 1) meets criteria for an intellectual disability, which would mean a measured IQ of 70-75 or lower and a measured Adaptive Functioning score of 70-75 or lower, 2) meets criteria for an Autism Spectrum Disorder based on an evaluation using the ADOS-2, SCQ, and expert clinical judgment based on DSM-5 ASD criteria, or 3) has a medically verified genetic condition (e.g., Down syndrome, Fragile X syndrome, Williams syndrome, Angelman syndrome, others) that is generally considered to be a developmental disability, and shows cognitive or adaptive functioning deficits (70-75 or below) although not necessarily deficits in both categories as would be needed for an Intellectual Disability diagnosis.

Exclusion Criteria:

• Siblings identified as typically developing will be excluded 1) with a score of 10 or higher on the SCQ-L, if a subsequent ADOS suggests that they have an ASD diagnosis, or 2) with a WASI-II score of 75 or lower.