Assessment & Diagnosis

On this page, you will find emerging and best practices for appropriate, accurate diagnosis and assessment to inform services and supports for individuals with I/DD, brain injuries, or other cognitive disabilities and a mental health condition. An accurate diagnosis is very important to receive appropriate services and treatment; however, it can be a complicated process for individuals with co-occurring conditions. For example, people can experience diagnostic overshadowing, which is the outdated idea that people with I/DD cannot also have mental health conditions.

• HELP With Emotional and Behavioural Concerns in Adults With Intellectual and Developmental Disabilities— Diagnostic tool using biopsychosocial factors that helps in the understanding of the causes of emotional and behavioral distress in adults with I/DD, which may stem from past trauma, undiagnosed medical conditions, or unrecognized support issues (Surrey Place, 2024)
• Stigma Experienced by Family Members of People With Intellectual and Developmental Disabilities: Multidimensional Construct— Article detailing results of using a self-report measure of stigma among families of people with I/DD and examining associations between family stigma and other variables (Mitter, Ali, and Scior, 2018)
• General Measurement Tools for Assessing Mental Health Problems Among Children and Adolescents with an Intellectual Disability: A Systematic Review— Article explaining how specialized mental health tools for children with intellectual disabilities are generally more reliable and valid than general tools (Halvorsen et al., 2022)
• Mental Health & Down Syndrome— Article that describes assessing mental illness in people with Down syndrome (National Down Syndrome Society, 2024)
• Addressing Brain Health in Adults With Intellectual Disabilities and Developmental Disabilities— Companion document to the GSA KAER Toolkit for Primary Care Teams written to address the needs of adults with I/DD who develop dementia and to raise awareness of the unique needs of adults living with I/DD (Gerontology Association of America, National Task Group on ID and Dementia Practices, Ohio Association of Community Boards, and the Ohio Council for Cognitive Health, 2024) 
• Persons With Intellectual and Developmental Disabilities in the Mental Health System: Part 1. Clinical Considerations— Article that provides a clinical overview of neurodevelopmental disabilities, mental health, and other conditions that co-occur with I/DD (Pinals, Hovermale, Mauch, and Anacker, 2022)
• The Challenge of Co-Occurring Mental Illness and Intellectual Disability in Young People (Video)— Webinar (1:01:02) to help clinical practitioners understand how to assess and adapt care for people with intellectual disabilities and mental health needs (Orygen, 2020)
• Community Living, Intellectual Disability and Extensive Support Needs: A Rights-Based Approach to Assessment and Intervention— Paper that analyzes the extent to which professional practices are aimed at promoting the right to community living for people with I/DD and extensive support needs, as well as the right to habilitation and rehabilitation and the right to privacy (Esteban, Navas, Verdugo, and Arias, 2021)
• Trauma Assessment in Youth and Adults With IDD (Video)— Webinar (1:04:15) that introduces trauma assessment tools developed, in part, by the National Child Traumatic Stress Network, as well as important assessment adaptations (Brian D. Tallant, LPC, 2020)
• Bringing It in the Room: Addressing the Impact of Racism on the Therapeutic Alliance— Article that, through clinical case examples, discusses the role of racism in therapeutic practices (Maharaj, Bhatt, and Gentile, 2021)

Books & Materials Requiring Purchase

• Diagnostic Manual – Intellectual Disability: A Textbook of Diagnosis of Mental Disorders in Persons With Intellectual Disability (Fletcher et al., 2017)