UNDERSTANDING DEVELOPMENTAL DIFFERENCES IN ADHD: EXPLORING PATTERNS OF SYMPTOMS, IMPAIRMENT, RISK, AND COMPENSATORY SKILLS BASED ON AGE OF INITIAL DIAGNOSIS by LAURA E. HLAVATY Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy Department of Psychological Sciences CASE WESTERN RESERVE UNIVERSITY January 2020 CASE WESTERN RESERVE UNIVERSITY SCHOOL OF GRADUATE STUDIES We hereby approve the thesis/dissertation of LAURA E. HLAVATY candidate for the degree of DOCTOR OF PHILOSOPHY *. Committee Chair ELIZABETH J. SHORT, PH.D. Committee Member SANDRA RUSS, PH.D. Committee Member MICHAEL J. MANOS, PH.D. Committee Member CHRISTOPHER BURANT, PH.D. Date of Defense APRIL 30, 2019 *We also certify that written approval has been obtained for any proprietary material contained therein. I dedicate this thesis to my loving husband and family. Without your patience, assistance, and encouragement, this pursuit would have never been possible. Table of Contents List of Tables ..................................................................................................................... vi List of Figures .................................................................................................................. vii Acknowledgements ......................................................................................................... viii Abstract .............................................................................................................................. 1 Introduction ........................................................................................................................ 3 ADHD Symptom Continuity Across Development ....................................................... 9 Persistence Over Time .................................................................................................. 10 Early versus Late Symptom Onset ............................................................................... 13 Factors that influence ADHD diagnosis........................................................................ 15 Temperament ............................................................................................................ 15 IQ .............................................................................................................................. 18 Behavioral Problems and Assets ............................................................................... 21 Current Study ................................................................................................................ 24 Questions and Hypotheses ........................................................................................ 26 Method .............................................................................................................................. 33 Participants .................................................................................................................... 33 Measures........................................................................................................................ 35 Procedure ....................................................................................................................... 39 Results .............................................................................................................................. 49 Descriptives ................................................................................................................... 49 Results of Exploratory and Confirmatory Factor Analyses .......................................... 52 CFQL ........................................................................................................................ 52 Behavioral Assets ..................................................................................................... 62 Structural Models .......................................................................................................... 73 Model 1: ADHD symptoms predicting age of ADHD diagnosis .............................. 76 Model 2: Impairment predicting age of ADHD diagnosis ........................................ 81 Model 3: IQ, Temperament, and Behavioral Assets predicting age of ADHD diagnosis ................................................................................................................... 90 Model 4: Testing Risk/Compensatory variables as confounders on the relationship between impairment and age of ADHD diagnosis variables ................ 97 Testing confounder effects ...................................................................................... 104 Final Model Description ............................................................................................. 107 Discussion ....................................................................................................................... 116 Results of Research Questions .................................................................................... 116 Implications ................................................................................................................. 124 Limitations .................................................................................................................. 130 Appendix ......................................................................................................................... 132 References ....................................................................................................................... 143 List of Tables Table 1. Participant Demographics and Diagnostic Subtype ............................................ 50 Table 2. Participant Demographics and Diagnostic Subtype based on Age Grouping .... 51 Table 3. CFQL EFA 5 Factor Solution ............................................................................. 54 Table 4. CFQL Factor Correlation Matrix ........................................................................ 55 Table 5. Model Development of CFQL 5 Factor Model .................................................. 57 Table 6. SEM Parameter Estimates for CFQL 5-Factor Model........................................ 60 Table 7. Items from Behavioral Assets that were eliminated during EFA ....................... 62 Table 8. Behavioral Assets EFA 6 Factor Solution .......................................................... 64 Table 9. Factor Correlation Matrix for the Behavioral Assets Questionnaire .................. 65 Table 10. Model Development of Behavioral Assets Questionnaire 6-Factor Model ...... 68 Table 11. SEM Parameter Estimates for Behavioral Assets 6-Factor Model ................... 70 Table 12. Description of Impairment, Risk/Compensatory, and Outcome Variables ...... 74 Table 13. Description of Impairment, Risk and Compensatory factors based on Age Groupings .......................................................................................................................... 75 Table 14. SEM Parameter Estimates for ARS Symptoms on Age ................................... 78 Table 15. SEM Parameter Estimates for Impairment predicting Age of ADHD diagnosis ........................................................................................................................... 84 Table 16. SEM Parameter Estimates for Risk/Compensatory factors impact on Age of ADHD Diagnosis .......................................................................................................... 93 Table 17. Regression Paths from Impairment to Age of Diagnosis tested for confounding effect of Risk/Compensatory Factors ........................................................ 106 Table 18. SEM Parameter Estimates for SEM Model of Relationship between Risk/Compensatory Factors, Impairment, & Age of ADHD Diagnosis ......................... 109 Appendix Table 1-A. Descriptives on Parent Education and Occupation ....................................... 132 Table 2-A. CFQL Item Correlations ............................................................................... 134 Table 3-A. Behavioral Assets Item Correlations ............................................................ 137 Table 4-A. Model Development of Impairment as a predictor of Age of ADHD Diagnosis......................................................................................................................... 139 Table 5-A. Model Development for Risk/Compensatory variables as predictors of Age of ADHD Diagnosis ................................................................................................ 140 Table 6-A. Model Development of Risk/Compensatory variables impact on Impairment to Age of ADHD Diagnosis ........................................................................ 141 List of Figures Figure 1. Hypothesized Model of ADHD Symptoms Impacting Age of ADHD Diagnosis........................................................................................................................... 26 Figure 2. Hypothesized Model of Impairment Impacting Age of ADHD Diagnosis ....... 27 Figure 3. Hypothesized Model of IQ impacting Age of ADHD Diagnosis, and IQ as a Confounder on the Relationship between Impairment and Age of ADHD Diagnosis ..... 29 Figure 4. Hypothesized Model of Temperament impacting Age of ADHD Diagnosis, and Temperament as a Confounder of the Relationship between Impairment and Age of ADHD Diagnosis .......................................................................................................... 31 Figure 5. Hypothesized