Psychology, Department of


First Advisor

Mario Scalora

Second Advisor

Sarah Gervais

Date of this Version


Document Type



Tevis, K. (2020). Long-Term Behavioral Health Care Unbundled: The Impact of Comorbidity and Aggression on Caregiver Strain and Service Costs for Individuals with Intellectual Disabilities. Theses, Dissertations, and Student Research: Department of Psychology.


A DISSERTATION Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Doctor of Philosophy, Major: Psychology (Social Psychology), Under Supervision of Professors Mario Scalora and Sarah Gervais. Lincoln, Nebraska: June, 2020

Copyright 2020 Kristine Tevis


Individuals with intellectual disabilities represent a unique population with an array of needs. High rates of comorbid mental and physical health conditions as well as the presence of disruptive behaviors pose significant challenges to service providers and funding entities. Existing cost models may underestimate these specialized needs and limit access to required services. Through secondary analysis of archival health data from individuals with intellectual disabilities at one agency in Nebraska (N=73), the current study examines how individual characteristics and aggression influence cost and caregiver strain from a systems theory perspective. Bivariate comparisons revealed that more severe aggression and more frequent aggressive behaviors (including verbal aggression, aggression against others, aggression against self, and aggression against property) relate to higher levels of caregiver strain and higher costs. Correlation and regression analyses revealed that existing rate models used to set service rates overlook significant factors when predicting actual costs. Individuals with comorbid physical and mental health conditions, especially those with serious and persistent mental illnesses, who also exhibit aggressive behaviors (measured by frequency and severity), significantly predict higher direct costs better than models that only account for levels of functioning. Despite consistent acuity based on similar behavioral severity ratings, IQ, and adaptive functioning scores, individuals served in extended family home settings displayed fewer aggressive behaviors and induced less strain on their caregivers, while receiving services at over $10,000 per month cost savings compared to their counterparts served in group home settings. Examination of emerging setting effects offers a progressive interpretation of the results with practical implications for developing rate-setting methodologies and public policy considerations.

Advisors: Mario Scalora and Sarah Gervais