AN EXTERNAL VALIDITY STUDY OF THE MMPI PERSONALITY DISORDER SCALES

Transcription

1 570 Journal of Clinical Psychology, July 1989, Vol. 45, No. 4 PROKOP, C. K., BRADLEY, L. A., MARGOLIS, R., &GENTRY, W. D. (1980). Multivariate analyses of the MMPI profiles of multiple pain patients. Journal of Personality Assessment, 44, STERNBACH, R. (1974). Pain patients: Traits and treatment. New York: Academic Press STRASSBERG, D., REIMHERR, F., WARD, M., RUSSELL, S., & COLE, A. (1980). The MMPI and chronic pain. Journal of Consulting Clinical Psychology, 49, WILTSE, L. L., ROCCHIO, P. D. (1975). Pre-operative psychological tests as predictors of success in the treatment of low back syndrome. Journal of Bone and Joint Surgery, 57A, AN EXTERNAL VALIDITY STUDY OF THE MMPI PERSONALITY DISORDER SCALES ALAN F. DUBRO AND SCOTT WETZLER Albert Einstein College of Medicine/Montefiore Medical Center This study examined the external validity of the MMPI Personality Disorder (PD) scales. Patients diagnosed with personality disorders (n = 23), according to a structured interview, were contrasted with medical control subjects and psychiatric patients with no personality disorder (n = 33). The MMPI PD scales could discriminate patients with any personality disorder and patients with specific clusters of personality disorders. Convergent validity was demonstrated by high correlations between the MMPI PD scales and the comparable Millon Clinical Multiaxial Inventory scales, as well as the number of DSM-111 personality disorder symptoms. This study represents a preliminary step in the external validation of the MMPI PD scales. The DSM-I11 highlights personality disorder diagnosis by creating a separate axis for the identification of personality disorders. Consequently, the assessment of these disorders has become increasingly important. Several new self-report inventories have been designed for Axis I1 diagnosis (Widiger & Frances, 1987), including one based on the pool of MMPI items (Morey, Waugh, & Blashfield, 1985). While the clinical scales of the MMPI have been used extensively to assess major psychopathology, the poor specificity of certain code type profiles (Hurt, Clarkin, Frances, Abrams, & Hunt, 1985; Morey & Smith, in press) makes them less useful for personality disorder diagnosis. Morey et al. s (1985) MMPI Personality Disorder Scales (MMPI PD scales) may be better suited for this purpose. The MMPI PD scales were developed through a rational/empirical approach (Wiggins, 1966). Experienced clinical psychologists selected items from the MMPI item pool that they determined were related to DSM-I11 axis I1 criteria. On the basis of these evaluations, preliminary scales were constructed for each personality disorder. The scales were refined further by removing items that did not discriminate between high and low scorers on the individual scales. Each of the individual PD scales demonstrated high internal consistency as measured by the Kuder-Richardson statistic, and a factor analysis of test items yielded a primary factor consistent with the DSM-111 personality disorder clusters (i.e., cluster l- odd or eccentric, cluster 2- emotionally labile and unstable, cluster 3- anxious or fearful ). Morey et al. (1985) also reported a number of predicted cor- Paper presented at the American Psychological Association Ninety-fifth Annual Meeting, August The authors gratefully acknowledge Stephen Hurt for his comments. Correspondence that concerns this article should be addressed to Alan F. Dubro, Ph.D., Divison of Psychology, The New York Hospital, Cornell University Medical Center, Westchester Division, 21 Bloomingdale Road, White Plains, NY

2 Validity of the MMPI PD Scales 571 relations between scores on the MMPI PD scales and scores on standard MMPI clinical scales. Three studies have examined the diagnostic efficiency and validity of the MMPI PD scales. Dubro, Wetzler, and Kahn (1988) found that these scale were both sensitive and specific for the general diagnosis of any DSM-I11 personality disorder, the diagnosis of DSM-I11 cluster 2 and 3 disorders, and the diagnosis of one individual personality disorder (Avoidant). In contrast, the PD scales tended to underdiagnose three other individual personality disorders (Dependent, Histrionic, and Borderline). That study used a reliable and valid criterion diagnosis based on a structured interview. Morey, Blashfield, Webb, and Jewel1 (1988) also reported that the MMPI PD scales were able to discriminate patients diagnosed with specific personality disorders and normal individuals, as well as patients with other personality disorders. Unfortunately, chart diagnoses, which have been unreliable, were used as the criterion. One unpublished study demonstrated convergent validity between the MMPI PD scales and the Millon Clinical Multiaxial Inventory (MCMI) Axis I1 scales (Greene & Farr, 1987). The present study represents a further attempt to investigate the validity of the MMPI PD scales using a reliable and valid Axis I1 criterion diagnosis. METHOD Subjects The sample consisted of patients (N = 56) who were receiving either medical or inpatient psychiatric treatment at a Veterans Administration hospital. Data were collected on hospitalized psychiatric patients and on a medical control group with no prior history of psychiatric disorder. Fifty-two (93To) patients who participated in the study were men. This figure is comparable in both the psychiatric and medical sample. The psychiatric patients were consecutive admissions to a treatment team and were judged on the basis of a chart review to be neither mentally retarded, organic, nor psychotic. Such pervasive and/or longstanding disorders would have complicated the assessment of baseline personality. The medical patients were identified initially through a surgery roster that was distributed in the hospital on a daily basis. Patients were seen within 3 days post-surgery and were asked to participate in the study. Approximately one-third of these patients either refused to participate or failed to complete the self-report questionnaires after they were interviewed. Over a 6-month period, 39 psychiatric patients participated in the study; 3 patients did not complete the self-report questionnaires and were excluded from the data analysis. Twenty medical patients participated in the study. Demographic characteristics of the sample are presented in a separate report (Dubro et al., 1988). Assessment Procedure Each patient was given the Structured Interview for the DSM-111 Personality Disorders (SIDP; Pfohl, Stangl, & Zimmerman, 1983; Stangl, Pfohl, Zimmerman, Bowers, & Corenthal, 1985) by a fourth-year clinical psychology graduate student. Reliability was evaluated by having a psychology intern sit in on interviews with 6 patients and make an independent personality disorder diagnosis. Interrater reliability, for the presence or absence of a personality disorder diagnosis, as assessed by kappa (Cohen, 1960; Spitzer & Fleiss, 1974), was.68. Subjects completed the full MMPI and the Millon Clinical Multiaxial Inventory (MCMI), a recently developed personality disorder self-report test (Millon, 1982). MMPI PD scale T scores were derived for the overlapping PD scales by converting raw scores on each of the test s scales to standardized scores using norms developed by Morey and Smith (in press). Raw scores on the MCMI were converted to base rate scores by use of Millon s (1982) norms.

3 512 Journal of Clinical Psychology, July 1989, Vol. 45, No. 4 RE s u L T s SIDP Criterion Diagnosis In the psychiatric sample, 61% (n = 22) of the patients met criteria for one or more personality disorders on the basis of the SIDP interview. Five percent (n = 1) of the control patients met criteria for a personality disorder. A case-by-case tabulation indicated that 4 patients were given DSM-I11 cluster 1 diagnoses, 15 cluster 2 diagnoses, and 15 cluster 3 diagnoses. Only four individual personality disorders (Histrionic, Borderline, Avoidant, and Dependent) were diagnosed with sufficient frequency (n > 5) to permit statistical analysis. The base rates and overlapping diagnoses for the personality disorders are reported in a previous study (Dubro et al., 1988). In all cases, the psychiatric patients received more than one diagnosis; the mean number of criterion diagnoses per psychiatric patient was 2.17 (SD = 1.4) Group Mean Data The MMPI PD scale scores of personality-disordered patients and non-personalitydisordered patients overall differed significantly (MANOVA, fll1, 441 = 3.86, p <.001). As Table 1 indicates, the personality-disordered patients had significantly higher T scores 0, -c.05) than non-personality-disordered patients on the following PD scales: Schizotypal, Paranoid, Borderline, Antisocial, Avoidant, Dependent, Compulsive, and Passive-Aggressive. Table 1 Mean MMPI PD T Scores for Personality-disordered and Non-personality-disordered Patients PD NPD Personality disorder (n = 23) (n = 33) P Histrionic ns Narcissistic ns Borderline Antisocial Dependent Ol Avoidant Compulsive Passive-Aggressive Paranoid Schizotypal Schizoid ns Note.-P~ = Personality Disorder; NPD = No Personality Disorder. Patients with DSM-111-defined clusters of personality disorders then were compared to patients with other personality disorders (OPD). Clusters 2 and 3 had sufficient numbers of patients to permit these analyses (n > 5). As Table 2 indicates, all scale elevations were in the expected direction, but not all comparisons were statistically significant. Cluster 2 patients had significantly higher scores on the Histrionic, Borderline, and Antisocial scales, and cluster 3 patients had significantly higher scores on the Dependent scale. Correlational Data The previous group mean analyses utilize a dichotomous variable- the presence or absence of a personality disorder diagnosis - that may obscure more subtle relation-

4 Validity of the MMPI PD Scales 573 ships. Correlations between comparable dimensions permit the uncovering of these relationships. As a result, we present correlations between scores on the MMPI PD scales and two dimensional ratings: the number of personality disorder symptoms possessed by each patient for each disorder, and scores on the MCMI Axis I1 scales. Table 2 Means and Standard Deviations for Cluster vs. Other Personality-disordered (OPD) Patients Cluster Diagnosis Criterion group OPD group t (54) 2 Histrionic 46.5 (8.2) 38.4 (8.2) 2.22 i 2 Narcissistic 48.3 (10.4) 38.8 (13.0) Borderline 63.8 (7.9) 54.9 (9.2) Antisocial 71.9 (12.1) 58.8 (15.6) Number of subjects n = 15 n=8 3 Avoidant 64.9 (7.0) 58.4 (8.9) Dependent 67.7 (8.5) 53.8 (9.5) 3.56* 3 Compulsive 62.6 (8.4) 58.6 (13.5).88 3 Passive-Aggress (9.3) 63.2 (10.6).77 Numbers of subjects n = 15 n=8 Note.-+p <.05. *p <.01. Table 3 presents the correlations between T scores on the MMPI PD Borderline, Histrionic, Avoidant, and Dependent scales, and mean T scores for cluster 2 and 3 scales with the number of symptoms scored on the comparable SIDP dimensions. All correla tions were significant (p <.01). Table 3 Correlations of the MMPI PD Scale Scores with the Number of SIDP Symptoms Personality disorder Cluster 2 Histrionic Borderline Cluster 3 Avoidant Dependent Correlation coefficient.58**.35*.46**.61**.59**.58** Note. - SIDP = Structured Interview for the DSM-I11 Personality Disorders. *p <.01. **p <.001. Table 4 presents correlations between the MMPI PD scales and their corresponding MCMI Axis I1 scales. All correlations with the exception of one (Antisocial) were significant, and they were also in the expected direction with one exception (Compulsive). DISCUSSION In our earlier report, the MMPI PD scales demonstrated moderate to good diagnostic efficiency for diagnosing any personality disorder and clusters of personality disorders

5 ~~~~~ ~~~ ~ 574 Journal of Clinical Psychology, July 1989, Vol. 4.5, No. 4 (Dubro et al., 1988). In this study, we have presented further evidence that concerns the validity of these scales. Personality-disordered patients have higher scores on the MMPI PD scales than did control subjects with no personality disorder; also, patients with particular clusters of personality disorders have elevations on the relevant scales in comparison to patients with other personality disorders. In general, the MMPI PD scales do appear to discriminate personality-disordered patients with fairly good specificity, although our findings are limited to DSM-111 clusters 2 and 3. Convergent validity was demonstrated by the robust correlations between the MMPI PD scale scores and MCMI scale scores, as well as their correlations with the number of symptoms scored on corresponding SIDP scales. Table 4 Correlations Between the MMPI PD Scales and the MCMI Scales Personality disorder Correlation coefficient Schizoid.35* Schizotypal.51** Paranoid.44** Histrionic.66** Narcissistic.55** Antisocial.14 Borderline.28 + Avoidant.65** Dependent.68** Compulsive -.42* Passive-Aggressive.50** Note. - MCMI = Millon Clinical Multiaxial Inventory. +p <.05. *p <.01. **p <.001. While this study has limitations with regard to the number of subjects who have cluster 1 disorders and the number of subjects in most individual personality disorder categories, some tentative conclusions can be drawn about the diagnostic usefulness of the MMPI PD scales in a male inpatient population. These scales may be used both as diagnostic indicators and as dimensional ratings. One apparent weakness, however, is that the Histrionic and Narcissistic scales appear to measure healthy components of personality functioning at moderate elevations, whereas they measure significant pathology at higher elevations (Dubro et al., 1988; Morey & Smith, in press). REFERENCES COHEN, J. (1960). A coefficient of agreement for nominal scales. Educational and Psychological Measurement, 20, DUBRO, A., WETZLER, S., 4 KAHN, M. (1988). A comparison of three self-report questionnaires for the diagnosis of DSM-I11 personality disorders. Journal of Personality Disorders, 2, GREENE, R., & FARR, S. (1987, September). Concordance among the MCMI and MMPI PD scales, Paper presented at the annual meeting of the American Psychological Association. HURT, S., CLARKIN, J., FRANCES, A,, ABRAMS, R., &HUNT, H. (1985). Discriminant validity of the MMPI for borderline personality disorder. Journal of Personality Assessment, 49, MILLON, T. (1982). Millon Clinical Multiaxial Inventory (MCMI). Minneapolis, MN: National Computer Systems.

6 Validity of the MMPI PD Scales 575 MOREY, L., BLASHFIELD, R., WEBB, W., & JEWELL, J. (1988). MMPI scales for DSM-I11 personality disorder; a preliminary validation. Journal of Clinical Psychology, 44, MOREY, L., & SMITH, M. (in press). Use of the MMPI with personality disorders. In R. Greene (Ed.), The MMPI: Use in specific diagnostic groups. Orlando, FL: Grune & Stratton. MOREY, L., WAUGH, M., & BLASHFIELD, R. (1985). MMPI scales for DSM-111 personality disorders. Journal of Personality Assessment, 49, PFOHL, B., STANGL, D., & ZIMMERMAN, M. (1983). Structured Interview for the DSM-IIIPersonality Disorders. Unpublished manual, University of Iowa. SPITZER, R., & FLEISS, J. (1974). A re-analysis of the reliability of psychiatric diagnosis: British Journal of Psychiatry, 37, STANGL, D., PFOHL, B., ZIMMERMAN, M., BOWERS, W., & CORENTHAL, C. (1985). A structured interview for the DSM-111 personality disorders. Archives of General Psychiatry, 42, WJDIGER, T., & FRANCES, A. (1987). Instruments and inventories for the measurement of personality disorders. Clinical Psychology Review, 7, WIGGINS, J. (1966). Substantive dimensions of self-report in the MMPI item pool. Psychological Monographs, 80, 22 (Whole No. 630). THE UTILITY OF MMPI SUBTLE, OBVIOUS SCALES FOR DETECTING FAKE GOOD AND FAKE BAD RESPONSE SETS GARY W. PETERSON AND DAVID ANTHONY CLARK Florida State University BERT BENNETT Forsyth Memorial Hospital Winston Salem, North Carolina The MMPI was administered twice to 40 graduate students to determine the utility of the Weiner subtle and obvious scales (D, HY, PD, PA, MA) for estimating how fake good and fake bad response sets might influence full scale scores. The first time, the MMPI was administered under standard conditions. Subjects then were divided randomly into two groups: fake good (complete MMPI for job application) and fake bad (qualify for psychotherapy). There were significant multivariate test effects (standard vs. response set) for the raw scores of all five obvious, subtle, and full scales. However, when raw scores were converted to T scores to ascertain practical significance, the obvious scales appeared to provide the most useful information to enhance the interpretation of full scale scores in normal populations. Cronbach (1970) encouraged the use of separate keys for subtle and transparent items to enhance the interpretation of scores on structured personality inventories. In this regard, he lauded the attempt by Weiner (1948) to develop subtle (S) and obvious (0) subscales for certain scales of the MMPI (D, HY, PD, PA, MA). Research on item subtlety and item transparency of the MMPI thus far has focused primarily on the degree to which selected sets of subtle and obvious items respond to various response sets. However, the effect of response sets on the five Weiner scalesperse has not been reported. For example, 146 subtle items taken collectively, revealed less pathology under the fake bad condition than under the standard condition, while 160 obvious items were manipulated successfully in the predicted direction (Anthony, 197 1). Under the condition of fake good for a job application and fake bad for therapeutic evaluation, the grand means for all subtle items and all obvious items were manipulated successfully