Ohio State University Nisonger Center

Susan Marie Havercamp

Marc J. Tassé

Background: Intellectual disability confers increased risk of mental illness; however, a robust prevalence study of the occurrence of mental illness in adults with intellectual disability (ID) has not been conducted in the United States. Present prevalence estimates, based on previous research in the United Kingdom (Cooper et al., 2007; Strømme &amp; Diseth, 2000), Australia (Morgan et al., 2008), and some U.S. studies (Fletcher et al., 2016; Reiss, 1994; Rojahn &amp; Tassé, 1996; Smiley, 2005;), have suggested that mental illness occurs in 30% to 50% of adults with intellectual disability. This rate of comorbidity of psychiatric disorders in persons with ID might be as much as twofold higher than what has been reported in the general population (SAMHSA, 2023; Steel et al., 2014). Co-occurring mental illness is associated with an increased intensity and complexity of support needs compared to adults with ID without comorbid psychiatric disorders (Rojahn et al., 2004; Tassé &amp; Wehmeyer, 2010). A systematic national study to determine more precise prevalence rates of mental disorders among adults with ID is needed to guide federal policy and programs. Study Purpose: The purpose of this research was to estimate prevalence rates of mental disorders among adults with intellectual disability in the US. Sample: We recruited a sample of approximately 500 adults (18+ years old) with intellectual disability (ID) and their caregivers/study partners (approximately 500 dyad pairs or approximately 1000 individuals in total) from across the United States (US). To estimate prevalence of mental illness, we leveraged the National Core Indicators (NCI) project (https://www.nationalcoreindicators.org/) sampling pool from 6 states (Michigan, North Carolina, Ohio, Oregon, Rhode Island, Virginia) that also have a University Center for Excellence in Developmental Disabilities (UCEDD) involved in coordinating the NCI project data collection in their state. We recruited adults with ID and their caregivers/study partners through the NCI sample in these states through convenience sampling. In general, the research sample mean age, sex, race, ethnicity, and ID level proportions were representative of the population of adults with ID surveyed by NCI data (P&gt;.10). Research sample data aligned with US Census data though our percentage of Hispanic/Latino individuals in the study sample was lower than the percentage in the general population. Methods: Primary measures (surveys) were administered via in-person structured research interviews with adults with ID and their caregivers/study partners before 2020. After 2020 primary measures were administered via virtual structured research interviews with adults with ID and their caregivers/study partners. The caregivers/study partners completed select secondary measures online before the research interview. The interview process was broken into multiple steps including an eligibility interview to determine if the AID was qualified to participate in the research based on study criteria. For this purpose, the WASI-2 and ABAS-3 measures were administered to determine AID eligibility. Primary Measures: Ohio State University researchers adapted these two measures for adults with ID in Study 1 of the Can You Hear Me Now? project. (a) The Diagnostic Interview for Adolescents and Adults with Intellectual Disability (DIAAID): Adult with intellectual Disability (AID) and Study Partner (SP) Versions (b) My Health and Wellbeing Survey (MHWBS) (AID) For more details about these measures, please see Related Publications. Secondary Measures: Key: (*) = The Ohio State University researchers did not produce this measure. They do not claim ownership of this measure. This measure was developed by other researchers and is protected by copyright. We purchased publisher copies and/or the rights to use this measure unless the measure was in the public domain. AID=Measure was administered to adult with intellectual disability SP=Measure was administered to caregiver/study partner Adaptive Behavior Assessment System (Third Edition) (ABAS-3)* (SP) The Behavior Problems Inventory for Individuals with ID (BPI-S)* (SP) Adapted Children’s Alexithymia Measure (CAM)* (SP) DIAAID Demographic Survey (SP) DIAAID Timeline of Reference Points (Visual Support for AID) DIAAID Demographic Survey (AID) Life Events for Persons with ID (BLESID)* (SP) Pre-Interview Training Module (AID) The Social Desirability Short Scale for Adults with ID (SDSS-ID)* (AID) Wechsler Abbreviated Scale of Intelligence (Second Edition) (WASI-2)* (AID) Other: Study Enrollment (Indicates whether an individual was determined to be eligible to participate in the research, and eligible individuals were enrolled into the study) Study Early Exit (Indicates whether an individual withdrew from the study early after being determined eligible but before completing one or more of the research measures) Interviewer Impression Scale (Interviewer perceptions of AID comprehension of questions asked through the research interview) DISCLAIMER (PLEASE READ): (a) This publicly available data set is PRELIMINARY as this research is ongoing through a subsequent grant from the same funder. The next round of data will become publicly available in 2029 once that grant is completed. (b) Due to ongoing refinement of adapted measures and the use of copyrighted measures, we did not upload the measures themselves. The accompanying data dictionaries should suffice. If you have questions about the measures used or have other general study questions, please contact the study investigators (havercamp.1@osu.edu, tasse.1@osu.edu). References: Cooper, S. A., Cooper, S. A., Smiley, E., Morrison, J., Williamson, A., &amp; Allan, L. (2007). Mental ill-health in adults with intellectual disabilities: Prevalence and associated features. British Journal of Psychiatry, 190, 27-35. Fletcher, R. J., Barnhill, J., &amp; Cooper, S. A. (2016). Diagnostic manual - Intellectual disability (2nd edition): A textbook of diagnosis of mental disorders in persons with intellectual disability (DM-ID-2). Kingston, NY: NADD Press. Morgan, V. A., Leonard, H., Bourke, J., &amp; Jablensky, A. (2008). Intellectual disability co‐occurring with schizophrenia and other psychiatric ill‐ness: Population‐based study. The British Journal of Psychiatry: The Journal of Mental Science, 193(5), 364–372. Reiss, S. (1994). Handbook of challenging behavior: Mental health aspects of mental retardation. Worthington, OH: IDS Publishing Corporation. Rojahn, J., Matson, J., L., Naglieri, J. A., &amp; Mayville, E. (2004). Relationship between psychiatric conditions and behavioral problems among adults with mental retardation. American Journal on Mental Retardation, 109, 21-33. Rojahn, J. &amp; Tassé, M. J. (1996). Psychopathology in mental retardation. In J. W. Jacobson &amp; J. A. Mulick (Eds.), Manual of diagnosis and professional practice in mental retardation (pp. 147-156). Washington, DC: American Psychological Association. Smiley, E. (2005). Epidemiology of mental health problems in adults with learning disability: An update. Advances in Psychiatric Treatment, 11, 214-222. Steel, Zachary, Z., Marnane, C., Iranpour, C., Chey, T., Jackson, J. W., Patel, V., &amp; Silove, D. (2014). The Global Prevalence of Common Mental Disorders: A Systematic Review and Meta-Analysis 1980-2013. International Journal of Epidemiology, 43(2), 476-493, doi: 10.1093/ije/dyu038. Strømme, P. &amp; Diseth, R. H. (2000). Prevalence of psychiatric diagnoses in children with mental retardation: Data from a population-based study. Developmental Medicine &amp; Child Neurology, 42, 266-270. Substance Abuse and Mental Health Services Administration. (2023). Key substance use and mental health indicators in the United States: Results from the 2022 National Survey on Drug Use and Health (HHS Publication No. PEP23-07-01-006, NSDUH Series H-58). Center for Behavioral Health Statistics and Quality, Substance Abuse and Mental Health Services Administration. Retrieved from https://www.samhsa.gov/data/report/2022-nsduh-annual-national-report. Tassé, M. J. &amp; Wehmeyer, M. L. (2010). Intensity of Support Needs in Relation to Co-occurring Psychiatric Disorders. Exceptionality, 18, 182-192.

National Institute on Disability, Independent Living, and Rehabilitation Research

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OSU RRTC NIDILRR Study 2 Prevalence - Can You Hear Me Now? Listening to People with Intellectual and Developmental Disabilities in Health Research

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