Performance in a Medico-legal Setting. Patricia Beaumont. Philosophy. University of Southern Queensland

Transcription

1 A Restructured MMPI-2: Establishing Incremental Validity and Underlying Patterns of Performance in a Medico-legal Setting Patricia Beaumont Being a report of an investigation submitted as a requirement for the award of Doctor of Philosophy University of Southern Queensland March 4, 2011

2 ii Statement of Originality I certify that the ideas, experimental work, results, analyses and conclusions reported in this dissertation are currently my own effort, except where due reference is made in the text. I also certify that this dissertation contains no material offered for any other award, except where otherwise acknowledged. Signed: Date: Patricia Beaumont Signed: Date: Dr. Graeme Senior (Principal Supervisor)

3 iii Abstract The Minnesota Multiphasic Personality Inventory-2 (MMPI-2) is a popular assessment tool used for the psychosocial assessment of personal injury litigants. However, there are inherent structural problems found in the MMPI-2 that question the utility of this test. In 2006, Goh restructured the MMPI-2 at the item level in order to provide a more accurate and reliable assessment device. Using a large sample of personal injury litigants, Goh rebuilt the MMPI-2 s scoring and analysis system specifically for the psychosocial assessment of personal injury litigants. Called the Minnesota Multiphasic Personality Inventory-2 for use with personal injury litigants (MMPI-2-PI), the development of the MMPI-2-PI used contemporary methods with the goal of enhancing internal consistency and eliminating item overlap. A unique feature of the MMPI-2-PI were items that were weighted according to the relevance of the constructs they measured which resulted in independently weighted scales and subscales. Since Goh s initial restructuring of the MMPI-2, Ben-Porath and Tellegen (2008) developed the Minnesota Multiphasic Personality Inventory-2-Restructured Form (MMPI-2-RF) also using contemporary methods to restructure the MMPI-2. Published in 2008, the MMPI- 2-RF was developed as an alternative version of the MMPI-2 for routine clinical psychosocial evaluation. While the MMPI-2-PI appeared to be a promising new approach for assessing personal injury litigants, it was still in its infancy. As such, the goals of this dissertation were to examine the Incremental validity and clinical utility of the MMPI-2-PI by comparing it to the more traditional MMPI-2 and more contemporary MMPI-2-RF. Using a sample of 2,989 personal injury litigants, analysis of the MMPI-2-PI included two comparisons: one with the MMPI-2-PI and MMPI-2; and the second between the MMPI-2-PI and the MMPI-2-RF. Comparisons between the MMPI-2-PI and the MMPI-2 demonstrated improved Incremental validity and

4 iv interpretability for the MMPI-2-PI. This comparison not only showed the MMPI-2-PI to be comparable to the MMPI-2, but also to be a better measurement device while demonstrating no evident scale redundancy and clear delineation of the constructs being measured. The second comparison indicated the MMPI-2-PI showed comparability to the MMPI-2-RF in assessing similar constructs. However, given some redundancy issues were evident in the MMPI-2-RF, incremental improvement was indicated for the MMPI-2-PI in assessing personal injury litigants. Further examination of the clinical and interpretive implications of using the MMPI-2-PI provided information on what constructs are more common (and not so common) within a medico-legal setting. Further to this, the majority of MMPI-2-PI scales and subscales demonstrated sensitivity to the constructs they were measuring and the diagnostic groups commonly seen in medico-legal evaluations. Independant interpretation of the majority of the MMPI-2-PI subscales was also demonstrated and recommended given there were different item weightings between the scales and subscales. This was an important consideration, given the subscales of the more traditional MMPI-2 are not recommended for interpretation if the parent scale is not clinically elevated. Finally, the MMPI-2-PI was further evaluated and compared to the MMPI-2 and MMPI-2-RF through two medico-legal case examples. These two case examples illustrated the discriminatory difficulties inherent in making diagnositic (or psychiatric) interpretations as opposed to behavioural (or psychological) interpretations, providing further weight to the argument that self reported psychosocial assessment devices should not be used for, or evaluated as diagnostic tools. Additionally, the MMPI-2-PI demonstrated clear delineation and clarification in identifying the constructs being measured without any notable loss of information while also demonstrating the advantages the weighted items have in effective scale endorsement. While the MMPI-2-PI could not be recommended

5 v for use outside of a medico-legal setting, this structure demonstrated it could provide a more effective and efficient psychosocial assessment of personal injury litigants when compared to the MMPI-2 and MMPI-2-RF.

6 vi Acknowledgements I would like to thank Dr. Graeme Senior for his patience, sound advice, and guidance I received throughout this incredibly challenging and rewarding experience you will continue to be someone I look up to and turn to for advice as I continue to strive for excellence within my profession. I would also like to thank Dr. Roger Greene for providing access to his data, Dr. Greene s patience and support was very much appreciated. I would like to thank my sister-in-law Linda, who put aside some of her Christmas holiday time to assist with what seemed like endless data checks. I would also like to acknowledge and thank my friend Narelle, who made herself available for hours, after working all day, to help me with endless data input procedures when I thought I it was all behind me. I must also thank my sister Cheryl for helping me in my final hours of completion...welcome home. And to my father Bill thanks for your support and for believing in me. I could not have completed this project without my mother, June, who was an angel watching over me during some of my more challenging moments when frustration and lack of confidence was a threatening force. I must also thank and remember my dear friend Gloria, who was a source of inspiration for me from the outset of my studies. Finally, I would like to thank my beautiful dog, Halee-girl, who helped create more balance in my life in the final year of my research, and at the time of writing these acknowledgements was chewing on my favourite pot plant. R.I.P. Halee-girl.

7 vii Table of Contents Statement of Originality... ii Abstract... iii Acknowledgements... vi List of Tables... xv List of Figures... xxiii CHAPTER ONE 1.1 Introduction Overview of Thesis CHAPTER TWO PERSONALITY TEST CONSTRUCTION AND STRUCTURAL CHANGES TO THE MMPI Approaches to Personality Test Construction Rational Approach Empirical Approach Internal Consistency Approach Construct Validation Approach Development of the MMPI and MMPI The MMPI The MMPI Continued Problems with the Test Item Overlap Heterogeneous Item Content Length of Test Interpretation Issues

8 viii 2.4 MMPI-2 RC Scales MMPI-2 RF CHAPTER THREE THE MMPI-2-PI 3.1 Assessment of Personal Injury Litigants Restructuring the MMPI The MMPI-2-PI Eliminates Structural Problems Summary CHAPTER FOUR PSYCHOMETRIC AND INTERPRETIVE CONSIDERATIONS 4.1 Standardised Scoring Demographic Norming Method Participants Materials Procedure Results and Discussion T Score Comparison Demographic Considerations Scoring the MMPI-2-PI Summary CHAPTER FIVE INCREMENTAL VALIDITY Method Participants, Materials, and Procedure... 70

9 ix Results and Discussion Alpha Coefficient Reading Level MMPI-2-PI and MMPI-2 Principal Components Analysis (PCA) Assumptions for PCA PCA Pattern Matrix Component Analysis Component 1 - Psychological Distress Component 2 - Negative Interpersonal Attitude Component 3 - Health Concerns Component 4 - Social Anxiety Component 5 - Psychotic Symptoms Component 6 - Antisocial Behaviours Component 7 - Anger Management Difficulties Component 8 - Social Withdrawal Component 9 - Family Difficulties Component 10 - Fears Component 11 - Lack of Positive Impression Management Component 12 - Masculinity Component 13 - Gastrointestinal Complaints Component Correlations Parent Scales Non-Retained Scales Summary

10 x CHAPTER SIX COMPARISON OF THE MMPI-2-PI AND THE MMPI-2-RF Method Participants, Materials, and Procedure Results and Discussion Alpha Coefficients Reading Level MMPI-2-PI and MMPI-2-RF Principal Components Analysis (PCA) Assumptions for PCA PCA Pattern Matrix Component Analysis Component 1 - Psychological Distress Component 2 - Psychotic Symptoms Component 3 - Neurological Concerns Component 4 - Antisocial Behaviours Component 5 - Passivity Component 6 - Social Withdrawal Component 7 - Elation Component 8 - Negative Interpersonal Attitude Component 9 - Fears Component 10 - Positive Impression Management Component 11 - Masculine Interests Component 12 - Feminine Interests Component 13 - Family Difficulties Component 14 - Gastrointestinal Complaints

11 xi Component Correlations Parent Scales Non-Retained Scales Summary CHAPTER SEVEN CLINICAL IMPLICATIONS FOR THE MMPI-2-PI 7.1 Structure of the MMPI-2-PI Method Participants, Materials, and Procedure Common theme of each scale Demonstrating scale and subscale directionality Examining subscale independence Representation for each diagnostic category Results and Discussion Emotional Domain Psychological Distress (PsD) Anger (Ang) Fears (Frs) Fear of the Dark (FOD) Irritability (Irr) Elation (Ela) Financial Worry (FiW) Physiological Domain Somatic Complaints (SoC) Gastrointestinal Problems (GaP)

12 xii Sexual Concerns (Sex) Cognitive Domain Cognitive Difficulties (CoD) Psychotic Symptoms (Psy) Paranoia (Par) Behavioural Domain Alcohol Abuse (Alc) Delinquency (Del) Stimulus Seeking (StS) Disciplined as Child (Dis) Interpersonal Domain Social Withdrawal (SoW) Negative Interpersonal Attitude (NIA) Timidity (Tim) Dissatisfaction with Self (DWS) Positive Impression (PoI) Family Relationship Difficulties (FRD) Gender Related Interests Masculinity (Mas) Femininity (Fem) Summary CHAPTER EIGHT ILLUSTRATIVE CASE EXAMPLES 8.1 Case Illustration of Ms. X STND Interpretation for Ms. X

13 xiii Psychiatric interpretation Psychological interpretation RFST Interpretation for Ms. X PIST Interpretation for Ms. X Structural Comparisons and Recommendations for Ms. X Case Illustration of Mr. Y STND Interpretation for Mr. Y Psychiatric interpretation Psychological interpretation RFST Interpretation for Mr. Y PIST Interpretation for Mr. Y Structural Comparisons and Recommendations for Mr. Y Summary CHAPTER NINE DISCUSSION AND CONCLUSION 9.1 Evaluating the MMPI-2-PI Comparison with the MMPI Comparison with the MMPI-2-RF Clinical Implications for the MMPI-2-PI Illustrative Case Examples Strengths of the MMPI-2-PI Limitations Future Directions References Appendix A

14 xiv Appendix B Appendix C Appendix D Appendix E Appendix F

15 xv List of Tables Table 2.1. MMPI-2 Scales and Subscales Table 2.2. MMPI-2-RF Scales Table 3.1. Components and Facets for the MMPI-2-PI Table 3.2. Items in the MMPI-2 and MMPI-2-PI s Suicide Scales Table 4.1. Diagnostic Representations of 1,842 Profiles in the Analysis in Order of Frequency Table 4.2. Descriptive Statistics for the MMPI-2-PI Components and Facets Table 4.3. Significant Correlations and T Test Scores for Demographic Variables Table 4.4. Gender Adjusted and Non-Gender Adjusted Frequency Rates for Fem, Frs Del, Mas, and StS Table 5.1. MMPI-2-PI and MMPI-2 Scales and Subscales Used in the PCA Table 5.2. Average Alpha Coefficients for the MMPI-2-PI and the MMPI-2 (N = 2,989) Table 5.3. Alpha Coefficient Range for US Normative Sample (N = 2,600) Table 5.4. Lexile Range for the MMPI-2-PI and MMPI-2 Comparison Table 5.5. Component Loadings for MMPI-2-PI (45 scales) and MMPI-2 (71 scales) Comparison Table 5.6. Scales and Loadings Retained in Component One Psychological Distress Table 5.7. Correlation Matrix for MMPI-2 Scales Retained in Component One Psychological Distress Table 5.8. Correlation Matrix for MMPI-2-PI Scales Retained in Component One Psychological Distress Table 5.9. Scales and Loadings Retained in Component 2 Negative Interpersonal Attitude... 89

16 xvi Table Correlation Matrix for MMPI-2 Scales Retained in Component 2 Negative Interpersonal Attitude Table Correlation Matrix for MMPI-2-PI Scales Retained in Component 2 Negative Interpersonal Attitude Table Scales and Loadings Retained in Component 3 Health Concerns Table Correlation Matrix for MMPI-2-PI Scales Retained in Component 3 Health Concerns Table Correlation Matrix for MMPI-2 Scales Retained in Component 3 Health Concerns Table Scales and Loadings Retained in Component 4 Social Anxiety Table Correlation Matrix for MMPI-2 Scales Retained in Component 4 Social Anxiety Table Correlation Matrix for MMPI-2-PI Scales Retained in Component 4 Social Anxiety Table Scales and Loadings Retained in Component 5 Psychotic Symptoms Table Correlation Matrix for MMPI-2-PI Scales Retained in Component 5 Psychotic Symptoms Table Correlation Matrix for MMPI-2 Scales Retained in Component 5 Psychotic Symptoms Table Scales and Loadings Retained in Component 6 Antisocial Behaviours Table Correlation Matrix for MMPI-2 Scales Retained in Component 6 Antisocial Behaviours Table Scales and Loadings Retained in Component 7 Anger Management Difficulties... 99

17 xvii Table Correlation Matrix for MMPI-2 Scales Retained in Component 7 Anger Management Difficulties Table Correlation Matrix for MMPI-2-PI Scales Retained in Component 7 Anger Management Difficulties Table Scales and Loadings Retained in Component 8 Social Withdrawal Table Correlation Matrix for MMPI-2 Scales Retained in Component 8 Social Withdrawal Table Scales and Loadings Retained in Component 9 Family Difficulties Table Correlation Matrix for MMPI-2 Scales Retained in Component 9 Family Difficulties Table Scales and Loadings Retained in Component 10 Fears Table Scales and Loadings Retained in Component 11 Lack of Positive Impression Management Table Correlation Matrix for MMPI-2-PI Scales Retained in Component 11 Lack of Positive Impression Management Table Scales and Loadings Retained in Component 12 Masculinity Table Scales and Loadings Retained in Component 13 Gastrointestinal Complaints Table Component Correlation Matrix for MMPI-2-PI/MMPI-2 Comparison Table Correlation Matrix for MMPI-2-PI and MMPI-2 Parent Scales Table Non-Retained Scales in the MMPI-2/MMPI-2-PI Comparison Table 6.1. MMPI-2-PI Scales and Subscales and MMPI-2-RF Scales Used in the PCA Table 6.2. Average Alpha Coefficients for the MMPI-2-PI and the MMPI-2-RF Clinical Sample (N = 2,989)

18 xviii Table 6.3. Alpha Coefficient Range for US Normative Sample Table 6.4. Lexile Range for the MMPI-2-PI and MMPI-2-RF Comparison Table 6.5. Component Loadings for MMPI-2-PI (45 scales) and MMPI-2-RF (43 scales) Comparison Table 6.6. Scales and Loadings Retained in Component 1 Psychological Distress Table 6.7. Correlation Matrix for MMPI-2-RF Scales Retained in Component 1 Psychological Distress Table 6.8. Correlations for MMPI-2-PI Scales Retained in Component 1 Psychological Distress Table 6.9. Scales and Loadings Retained in Component 2 Psychotic Symptoms Table Correlation Matrix for MMPI-2-RF Scales Retained in Component 2 Psychotic Symptoms Table Scales and Loadings Retained in Component 3 Neurological Concerns Table Correlations for MMPI-2-PI Scales Retained in Component 3 Neurological Concerns Table Correlation Matrix for MMPI-2-RF Scales Retained in Component 3 Neurological Concerns Table Scales and Loadings Retained in Component 4 Antisocial Behaviours Table Correlation Matrix for MMPI-2-RF Scales Retained in Component 4 Antisocial Behaviours Table Scales and Loadings Retained in Component 5 Passivity Table Scales and Loadings Retained in Component 6 Social Withdrawal Table Correlation Matrix for MMPI-2-PI Scales Retained in Component 6 Social Withdrawal

19 xix Table Correlation Matrix for MMPI-2-RF Scales Retained in Component 6 Social Withdrawal Table Scales and Loadings Retained in Component 7 Elation Table Scales and Loadings Retained in Component 8 Negative Interpersonal Attitude Table Scales and Loadings Retained in Component 9 Fears Table Correlations for MMPI-2-PI Scales Retained in Component 9 Fears Table Scales and Loadings Retained in Component 10 Positive Impression Management Table Scales and Loadings Retained in Component 11 Masculine Interests Table Scales and Loadings Retained in Component 12 Feminine Interests Table Scales and Loadings Retained in Component 13 Family Difficulties Table Scales and Loadings Retained in Component 14 Gastrointestinal Complaints Table Component Correlation Matrix for MMPI-2-PI/MMPI-2-RF Comparison Table Correlation Matrix for MMPI-2-PI and MMPI-2-RF Parent Scales Table Non-Retained Scales in the MMPI-2-PI/MMPI-2-RF Comparison Table 7.1. Proportion of Profiles for the Psychological Distress Scale and Subscales Table 7.2. Proportion of Individuals within each Diagnostic Category Elevating the Psychological Distress Scale and Subscales (T 65) Table 7.3. Proportion of Profiles for the Anger Scale and Subscales Table 7.4. Proportion of Individuals within each Diagnostic Category Elevating the Anger Scale and Subscales (T 65) Table 7.5. Proportion of Profiles for the Fears Scale and Subscales

20 xx Table 7.6. Proportion of Individuals within each Diagnostic Category Elevating the Fears Scale and Subscales (T 65) Table 7.7. Proportion of Individuals within each Diagnostic Category Elevating the Fear of the Dark Scale (T 65) Table 7.8. Proportion of Individuals within each Diagnostic Category Elevating the Irritability Scale (T 65) Table 7.9. Proportion of Individuals within each Diagnostic Category Elevating the Elation Scale (T 65) Table Proportion of Individuals within each Diagnostic Category Elevating the Financial Worry Scale (T 65) Table Proportion of Profiles for the Somatic Complaints Scale and Subscales Table Proportion of Individuals within each Diagnostic Category Elevating the Somatic Complaints Scale and Subscales (T 65) Table Proportion of Individuals within each Diagnostic Category Elevating the Gastrointestinal Problems Scale (T 65) Table Proportion of Individuals within each Diagnostic Category Elevating the Sexual Concerns Scale (T 65) Table Proportion of Individuals within each Diagnostic Category Elevating the Cognitive Difficulties Scale (T 65) Table Proportion of Profiles for the Psychotic Symptoms Scale and Subscales Table Proportion of Individuals within each Diagnostic Category Elevating the Psychotic Symptoms Scale and Subscales (T 65) Table Proportion of Individuals within each Diagnostic Category Elevating the Paranoia Scale (T 65)

21 xxi Table Proportion of Individuals within each Diagnostic Category Elevating the Alcohol Abuse Scale (T 65) Table Proportion of Individuals within each Diagnostic Category Elevating the Delinquency Scale (T 65) Table Proportion of Individuals within each Diagnostic Category Elevating the Stimulus Seeking Scale (T 65) Table Proportion of Individuals within each Diagnostic Category Elevating the Disciplined as Child Scale (T 65) Table Proportion of Profiles for the Social Withdrawal Scale and Subscales Table Proportion of Individuals within each Diagnostic Category Elevating the Social Withdrawal Scale and Subscales (T 65) Table Proportion of Profiles for the Negative Interpersonal Attitude Scale and Subscales Table Proportion of Individuals within each Diagnostic Category Elevating the Negative Interpersonal Attitude Scale and Subscales (T 65) Table Proportion of Profiles for the Timidity Scale and Subscales Table Proportion of Individuals within each Diagnostic Category Elevating the Timidity Scale and Subscales (T 65) Table Proportion of Profiles for the Dissatisfaction with Self Scale and Subscales Table Proportion of Individuals within each Diagnostic Category Elevating the Dissatisfaction with Self Scale and Subscales (T 65) Table Proportion of Profiles for the Positive Impression Scale and Subscales Table Proportion of Individuals within each Diagnostic Category Elevating the Positive Impression Scale and Subscales (T 65)

22 xxii Table Proportion of Individuals within each Diagnostic Category Elevating the Family Relationship Difficulties Scale (T 65) Table Proportion of Profiles for the Masculinity Scale and Subscales Table Proportion of Individuals within each Diagnostic Category Elevating the Masculinity Scale and Subscales (T 65) Table Proportion of Profiles for the Femininity Scale and Subscales Table Proportion of Individuals within each Diagnostic Category Elevating the Femininity Scale and Subscales (T 65) Table Summary of the Clinical Implications for the MMPI-2-PI s Scales and Subscales Table 8.1. MMPI-2 Profile of Ms. X Table 8.2. MMPI-2-RF Profile of Ms. X Table 8.3. MMPI-2-PI Profile of Ms. X Table 8.4. Items for the PIST and RFST Anxiety Related Scales Table 8.5. Items for the PIST and RFST Shyness Related Scales Table 8.6. MMPI-2 Profile of Mr. Y Table 8.7. MMPI-2-RF Profile of Mr. Y Table 8.8. MMPI-2-PI Profile of Mr. Y Table 8.9. Items for the PIST and RFST Social Avoidance Scales Table Items for the PIST and RFST Family Difficulties Scales

23 xxiii List of Figures Figure 5.1. Flow chart of the MMPI-2-PI/MMPI-2 validation process Figure 5.2. Scatterplot of Psy-De and SoC-HC Figure 6.1. Flow chart of the MMPI-2-PI/MMPI-2-RF validation process Figure 7.1. The six domains of the 25 components in the MMPI-2-PI (N = 400 items) Figure 7.2. Proportion of subscale elevations (T 65) within the Psychological Distress scale Figure 7.3. Proportion of subscale elevations (T 65) within the Anger scale Figure 7.4. Proportion of subscale elevations (T 65) within the Fears scale Figure 7.5. Proportion of subscale elevations (T 65) within the Somatic Complaints scale Figure 7.6. Proportion of subscale elevations (T 65) within the Psychotic Symptoms scale Figure 7.7. Proportion of subscale elevations (T 65) within the Social Withdrawal scale Figure 7.8. Proportion of subscale elevations (T 65) within the Negative Interpersonal Attitude scale Figure 7.9. Proportion of subscale elevations (T 65) within the Timidity scale Figure Proportion of subscales demonstrating clinical significance (DWS-Fe, T 65 and T 35; DWS-Ap, T 35) within the Dissatisfaction with Self scale Figure Proportion of subscale elevations (T 65) within the Positive Impression scale Figure Proportion of subscale elevations (Mas-SI, T 65; Mas-NI, T = 57-64) within the Masculinity scale Figure Proportion of subscale elevations (T 65) within the Femininity scale