Psychological Reporh, 1991, 69, 1235-1246. O Psychological Reports 1991
T H E PERSONALITY INVENTORY SCALES: A SELF-RATING CLINICAL INSTRUMENT FOR DIAGNOSIS O F PERSONALITY DISORDER ' J. WESLEY BURGESS Department of Psychiatry and Behavioral Sciences Stunford University Medical Center Summary.-A personality inventory was developed as an aid in securing history and beliefs relevant to the assessment of personality structure and the diagnosis of personality disorders. The inventory was developed by restating DSM diagnostic criteria in everyday language, rewording the resulting statements in the form of TrueIFalse questions, and placing these questions in a short, self-paced booklet which subjects could complete in about 15 minutes. The following assessments were made and discussed: construct validity, split-half reliability, test-retest reliability, comparison with a standardized interview, and comparison with actual cl~nicalassessments. The personality inventory is discussed as a useful accompaniment to the diagnostic interview in clinical settings and for research into personality structure and personality disorders.
Currently there are available to the clinician and researcher many tools for the assessment and dagnosis of personality and personality disorders. These tools include projective tests such as the Rorschach (Exner, 1978, 1982, 1985), standardized multiple-choice tests such as the MMPI (Morey, Waugh, & Blashfield, 1985; Morey, Blashfield, Webb, & Jewel, 1988; Streiner & Miller, 1988), the Millon Inventory (Millon, 1984, 1985; McMahon, Flym, & Davidson, 1985; Widiger, Williams, Spitzer, & Frances, 1985), and structured interview examinations (Stangl, Pfohl, Zimmerman, Bowers, & Corenthal, 1985; Widiger & Frances, 1987; Loranger, Susman, Oldham, & Russakof, 1987; Kolb & Gunderson, 1987). Although these tools are used extensively, there is not always a high concordance among them (Angus & Marziali, 1988; Streiner & Miller, 1988), so often the clinical interview between clinician and patient is preferentially used. Although the understanding of personality disorders is still evolving (e.g., Burgess, 1990, 1991a, 1991b), diagnosis frequently is based on the American Psychiatric Association's Diagnostic and Statistical Manual's personality disorders (APA, 1987). A glance at the list of DSM diagnostic statements shows that almost all of the criteria are either historical facts known by the patient or beliefs held by the patient; in other words, the patient is the primary source of information used for diagnosis. For diagnostic assess-
'Address inquiries to J. Wesley Burgess, Ph.D., M.D., Director, Adolescent Division, The Center for Mood Disorders, 1990 S. Bundy Dr., Suite 790, Los Angeles, CA 90025. The author thanks Drs. Vincent P. Zarconi, Roy King, and Herbert Leiderman for discussions and encouragement.
1236
J. W. BURGESS
ment, the clinician usually must sit down with the patient and ask questions covering as many of the diagnostic criteria statements as possible. I n practice, there is rarely time to screen patients across all criteria; in an informal survey of clinicians in the area, I learned that only a handful of the full complement of Axis I1 diagnostic statements are asked by most clinicians most of the time. The personality inventory described here was developed to address this need to acquire a more comprehensive survey of Axis I1 information without placing an additional burden on the clinician or patient. Although similar at first glance, we intend the instrument to be fundamentally different in content and use than any of the assessment tools mentioned above. Rather than providing another yardstick for personality assessment, the personality inventory is intended to be used to facilitate use of existing criteria and to amplify the clinician's own personal interview assessment. I n essence, the inventory can be used as a self-report first step before a &rect interview, and the information acquired can then be expanded in the following interview evaluation. Unlike the other tools mentioned above, the personality inventory is meant to be taken into the interview, if desired, and answers reviewed, clarified, and discussed with the patient; in other words, the inventory can become a part of the interview examination. Used in this way, the validity and reliability of the personality inventory would be dependent on the limits of the DSM classification system and the skills of the individual clinical interviewer. However, as a self-report instrument, validity and reliability can be assessed for the personality inventory and should be of interest to those who use it. This paper describes the instrument, briefly discusses its development, and gives the results of initial measurements of validity and reliability.
The Instrument The Personality Inventory Scales consist of 103 True-False questions (see Appendix I, pp. 1242-1244). Each question corresponds to one of the DSM Axis I1 diagnostic statements. For example, Diagnostic Statement 4 of Dependent Personality Disorder, which reads "has difficulty initiating projects or doing things on his or her own," is represented in the inventory by TrueIFalse Question 3: "It's really difficult for me to start projects or do things on my own." I n practice, the subject is presented with the items and instructions are read together with the clinician before starting. There is no time limit, the personality inventory can be completed by most subjects in about 15 minutes. Scoring can be accomplished in about 5 minutes by following directions given in the key (see Appendix 11, pp. 1245-1246). DSM also provides criteria to be rated by the clinician: constricted affect, odd dress and behavior, and odd speech. If the clinician determines
PERSONALITY SCALES
1237
these are present according to the definitions given in the key, points are added to the scores of the corresponding personality categories, following directions given in the key. The DSM Axis I1 diagnoses are made by comparing the number of symptoms present with a criterion number for each personality category (e.g., 1 4 of 7 criteria for Paranoid Personality; APA, 1987). Scores on the personality inventory are obtained similarly by comparing the score in each personahty category with the criterion number listed in the key (Appendix 11, pp. 1245-1246). Because subjects may not be frank in their responses, ten questions are presented on the inventory which are unrelated to personality categories but require the subject to endorse mildly negative statements (e.g., "When I'm sick I sometimes get irritable with people"). We hypothesize that subjects unwilling to endorse their own symptoms may also fail to endorse mildly negative questions on this scale and may show a low score on the V Scale category. However, until this experimental scale is clinically validated, its clinical use is limited; it is included for investigation.
Development of the Instrument Each DSM personality diagnostic statement (APA, 1987) was arranged in random order using a table of random numbers. Each statement was then rewritten into first person, present tense and edited for vocabulary to be in nontechnical, everyday English usage. Statements were then submitted to editors blind to the manipulation (to check understandability and clarity) and to mental health professionals to verify that statements reflected underlying content of original diagnostic criteria. The resulting statements were compiled into booklet format, with instructions for subjects to mark statements True or False, according to their own lives and beliefs. I/alidity and Reliability Studies Construct validity of the Personality Inventory Scales is based on the DSM system (APA, 1987) and cannot be more valid than its diagnostic conception. Currently, the DSM system is accepted and used in practice, although other systems are available (Morey, et al., 1985, 1988; Millon, 1984, 1985; Widiger, et al., 1985). As these systems continue to be investigated and revised, we expect construct validity will be better understood and strengthened. Split-half reliability provides a measure of internal validity of the measures (i.e., do several questions measure the same thing?). Questions were divided between first and second halves of the inventory, so that halves of the test could be compared across each diagnostic category. Subjects were 50 adults, aged 18 to 65 years, presenting for psychiatric assessment. Pearson
1238
J. W. BURGESS
product-moment correlation was used to compare scores between the first and second halves of each test (Mosteller & Tukey, 1977). Test-retest reliability provides a measure of stability of test results over time (i.e., do subjects answer the same way at different times?). Subjects were 24 adults, aged 18 to 65 years, presenting for psychiatric assessment. The subjects were subsequently retested after an interval of no less than 2 weeks. The interval of 2 weeks was chosen as a practical compromise; we hope investigators will address long-term reliability of both our scales and underlying diagnostic criteria. The Pearson product-moment correlation was used to compare scores between the first and second tests (Mosteller & Tukey, 1977). Comparison with an interview provides another measure of concordance validity. The Loranger Personality Disorder Examination (Loranger, et al., 1987) is a DSM-based interview which can be given in less than 2 hours and derives DSM diagnoses from questions concerning work, self, interpersonal relations, affects, reality-testing, and impulse control. We administered the Loranger interview and the n e b inventory to 20 adults, aged 21 to 43 years, on an all-male inpatient milieu therapy ward (the interview was administered as part of a larger unpublished study). Pearson product-moment correlation was used to compare scores between the two tests (Mosteller & Tukey, 1977). Comparison with clinical assessment provides a measure of the concordance between test results and diagnoses solely based on clinical assessments. Subjects were 65 adults, aged 18 to 65 years, presenting for psychiatric assessment. Patients were included if they had a prior diagnostic history confirmed by two independent mental health professionals using DSM-IIIR criteria. Scores on the personality inventory were compared with prior clinical diagnosis using a chi-squared test for independent categorical data (Sokal & Rohlf, 1969). RESULTS Split-half reliability of summed scores for all personality categories was 0.942 between first and second halves of the test (F,,,, = 378.70, p < .00001). Correlations were significant for all of the personality categories ( p < .025) as shown in Table 1 but were low for schizoid (.51), histrionic (.33), and obsessive-compulsive categories (.40). Test-retest reliability of summed scores for all personality categories was 0.943 between the first and second test sessions (F,,,, = 178.85, p < .00001). Correlations were significant for all of the individual personality categories (p < ,005) as shown in Table 1. Comparison with an interview showed a correlation of 0.388 for summed scores of all personality categories compared between the Loranger Personality Disorder Examination and our personality inventory scales (F,,,, =
PERSONALITY SCALES
1239
TABLE 1 PERSONALITY INVENTORY SCALES:SPLIT-HALF A N D TEST-RETEST , R E u A s m M ~ S L I R E(ns S = 50 A N D 24)
Scales
Split-half
Test-Retest
rf
rf
Interview Exam: r t
Paranoid
Schizoid Schizotypal Antisocial Borderline Histrionic Narcissistic
Avoidant Dependent
Obsessive-Compulsive Passive-Aggressive .59 .72 .22 tp
T H E PERSONALITY INVENTORY SCALES: A SELF-RATING CLINICAL INSTRUMENT FOR DIAGNOSIS O F PERSONALITY DISORDER ' J. WESLEY BURGESS Department of Psychiatry and Behavioral Sciences Stunford University Medical Center Summary.-A personality inventory was developed as an aid in securing history and beliefs relevant to the assessment of personality structure and the diagnosis of personality disorders. The inventory was developed by restating DSM diagnostic criteria in everyday language, rewording the resulting statements in the form of TrueIFalse questions, and placing these questions in a short, self-paced booklet which subjects could complete in about 15 minutes. The following assessments were made and discussed: construct validity, split-half reliability, test-retest reliability, comparison with a standardized interview, and comparison with actual cl~nicalassessments. The personality inventory is discussed as a useful accompaniment to the diagnostic interview in clinical settings and for research into personality structure and personality disorders.
Currently there are available to the clinician and researcher many tools for the assessment and dagnosis of personality and personality disorders. These tools include projective tests such as the Rorschach (Exner, 1978, 1982, 1985), standardized multiple-choice tests such as the MMPI (Morey, Waugh, & Blashfield, 1985; Morey, Blashfield, Webb, & Jewel, 1988; Streiner & Miller, 1988), the Millon Inventory (Millon, 1984, 1985; McMahon, Flym, & Davidson, 1985; Widiger, Williams, Spitzer, & Frances, 1985), and structured interview examinations (Stangl, Pfohl, Zimmerman, Bowers, & Corenthal, 1985; Widiger & Frances, 1987; Loranger, Susman, Oldham, & Russakof, 1987; Kolb & Gunderson, 1987). Although these tools are used extensively, there is not always a high concordance among them (Angus & Marziali, 1988; Streiner & Miller, 1988), so often the clinical interview between clinician and patient is preferentially used. Although the understanding of personality disorders is still evolving (e.g., Burgess, 1990, 1991a, 1991b), diagnosis frequently is based on the American Psychiatric Association's Diagnostic and Statistical Manual's personality disorders (APA, 1987). A glance at the list of DSM diagnostic statements shows that almost all of the criteria are either historical facts known by the patient or beliefs held by the patient; in other words, the patient is the primary source of information used for diagnosis. For diagnostic assess-
'Address inquiries to J. Wesley Burgess, Ph.D., M.D., Director, Adolescent Division, The Center for Mood Disorders, 1990 S. Bundy Dr., Suite 790, Los Angeles, CA 90025. The author thanks Drs. Vincent P. Zarconi, Roy King, and Herbert Leiderman for discussions and encouragement.
1236
J. W. BURGESS
ment, the clinician usually must sit down with the patient and ask questions covering as many of the diagnostic criteria statements as possible. I n practice, there is rarely time to screen patients across all criteria; in an informal survey of clinicians in the area, I learned that only a handful of the full complement of Axis I1 diagnostic statements are asked by most clinicians most of the time. The personality inventory described here was developed to address this need to acquire a more comprehensive survey of Axis I1 information without placing an additional burden on the clinician or patient. Although similar at first glance, we intend the instrument to be fundamentally different in content and use than any of the assessment tools mentioned above. Rather than providing another yardstick for personality assessment, the personality inventory is intended to be used to facilitate use of existing criteria and to amplify the clinician's own personal interview assessment. I n essence, the inventory can be used as a self-report first step before a &rect interview, and the information acquired can then be expanded in the following interview evaluation. Unlike the other tools mentioned above, the personality inventory is meant to be taken into the interview, if desired, and answers reviewed, clarified, and discussed with the patient; in other words, the inventory can become a part of the interview examination. Used in this way, the validity and reliability of the personality inventory would be dependent on the limits of the DSM classification system and the skills of the individual clinical interviewer. However, as a self-report instrument, validity and reliability can be assessed for the personality inventory and should be of interest to those who use it. This paper describes the instrument, briefly discusses its development, and gives the results of initial measurements of validity and reliability.
The Instrument The Personality Inventory Scales consist of 103 True-False questions (see Appendix I, pp. 1242-1244). Each question corresponds to one of the DSM Axis I1 diagnostic statements. For example, Diagnostic Statement 4 of Dependent Personality Disorder, which reads "has difficulty initiating projects or doing things on his or her own," is represented in the inventory by TrueIFalse Question 3: "It's really difficult for me to start projects or do things on my own." I n practice, the subject is presented with the items and instructions are read together with the clinician before starting. There is no time limit, the personality inventory can be completed by most subjects in about 15 minutes. Scoring can be accomplished in about 5 minutes by following directions given in the key (see Appendix 11, pp. 1245-1246). DSM also provides criteria to be rated by the clinician: constricted affect, odd dress and behavior, and odd speech. If the clinician determines
PERSONALITY SCALES
1237
these are present according to the definitions given in the key, points are added to the scores of the corresponding personality categories, following directions given in the key. The DSM Axis I1 diagnoses are made by comparing the number of symptoms present with a criterion number for each personality category (e.g., 1 4 of 7 criteria for Paranoid Personality; APA, 1987). Scores on the personality inventory are obtained similarly by comparing the score in each personahty category with the criterion number listed in the key (Appendix 11, pp. 1245-1246). Because subjects may not be frank in their responses, ten questions are presented on the inventory which are unrelated to personality categories but require the subject to endorse mildly negative statements (e.g., "When I'm sick I sometimes get irritable with people"). We hypothesize that subjects unwilling to endorse their own symptoms may also fail to endorse mildly negative questions on this scale and may show a low score on the V Scale category. However, until this experimental scale is clinically validated, its clinical use is limited; it is included for investigation.
Development of the Instrument Each DSM personality diagnostic statement (APA, 1987) was arranged in random order using a table of random numbers. Each statement was then rewritten into first person, present tense and edited for vocabulary to be in nontechnical, everyday English usage. Statements were then submitted to editors blind to the manipulation (to check understandability and clarity) and to mental health professionals to verify that statements reflected underlying content of original diagnostic criteria. The resulting statements were compiled into booklet format, with instructions for subjects to mark statements True or False, according to their own lives and beliefs. I/alidity and Reliability Studies Construct validity of the Personality Inventory Scales is based on the DSM system (APA, 1987) and cannot be more valid than its diagnostic conception. Currently, the DSM system is accepted and used in practice, although other systems are available (Morey, et al., 1985, 1988; Millon, 1984, 1985; Widiger, et al., 1985). As these systems continue to be investigated and revised, we expect construct validity will be better understood and strengthened. Split-half reliability provides a measure of internal validity of the measures (i.e., do several questions measure the same thing?). Questions were divided between first and second halves of the inventory, so that halves of the test could be compared across each diagnostic category. Subjects were 50 adults, aged 18 to 65 years, presenting for psychiatric assessment. Pearson
1238
J. W. BURGESS
product-moment correlation was used to compare scores between the first and second halves of each test (Mosteller & Tukey, 1977). Test-retest reliability provides a measure of stability of test results over time (i.e., do subjects answer the same way at different times?). Subjects were 24 adults, aged 18 to 65 years, presenting for psychiatric assessment. The subjects were subsequently retested after an interval of no less than 2 weeks. The interval of 2 weeks was chosen as a practical compromise; we hope investigators will address long-term reliability of both our scales and underlying diagnostic criteria. The Pearson product-moment correlation was used to compare scores between the first and second tests (Mosteller & Tukey, 1977). Comparison with an interview provides another measure of concordance validity. The Loranger Personality Disorder Examination (Loranger, et al., 1987) is a DSM-based interview which can be given in less than 2 hours and derives DSM diagnoses from questions concerning work, self, interpersonal relations, affects, reality-testing, and impulse control. We administered the Loranger interview and the n e b inventory to 20 adults, aged 21 to 43 years, on an all-male inpatient milieu therapy ward (the interview was administered as part of a larger unpublished study). Pearson product-moment correlation was used to compare scores between the two tests (Mosteller & Tukey, 1977). Comparison with clinical assessment provides a measure of the concordance between test results and diagnoses solely based on clinical assessments. Subjects were 65 adults, aged 18 to 65 years, presenting for psychiatric assessment. Patients were included if they had a prior diagnostic history confirmed by two independent mental health professionals using DSM-IIIR criteria. Scores on the personality inventory were compared with prior clinical diagnosis using a chi-squared test for independent categorical data (Sokal & Rohlf, 1969). RESULTS Split-half reliability of summed scores for all personality categories was 0.942 between first and second halves of the test (F,,,, = 378.70, p < .00001). Correlations were significant for all of the personality categories ( p < .025) as shown in Table 1 but were low for schizoid (.51), histrionic (.33), and obsessive-compulsive categories (.40). Test-retest reliability of summed scores for all personality categories was 0.943 between the first and second test sessions (F,,,, = 178.85, p < .00001). Correlations were significant for all of the individual personality categories (p < ,005) as shown in Table 1. Comparison with an interview showed a correlation of 0.388 for summed scores of all personality categories compared between the Loranger Personality Disorder Examination and our personality inventory scales (F,,,, =
PERSONALITY SCALES
1239
TABLE 1 PERSONALITY INVENTORY SCALES:SPLIT-HALF A N D TEST-RETEST , R E u A s m M ~ S L I R E(ns S = 50 A N D 24)
Scales
Split-half
Test-Retest
rf
rf
Interview Exam: r t
Paranoid
Schizoid Schizotypal Antisocial Borderline Histrionic Narcissistic
Avoidant Dependent
Obsessive-Compulsive Passive-Aggressive .59 .72 .22 tp
