SCREENING FOR BORDERLINE PERSONALITY DISORDER IN OUTPATIENT YOUTH

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1 Journal of Personality Disorders, 22(4), , The Guilford Press SCREENING FOR BORDERLINE PERSONALITY DISORDER IN OUTPATIENT YOUTH Andrew M Chanen, MBBS, MPM, FRANZCP, Martina Jovev, PhD, Danica Djaja, BmedSci, Emma McDougall, BSc, Hok Pan Yuen, MSc, David Rawlings, DPhil, and Henry J Jackson, PhD, FAPS Young people with borderline personality disorder (BPD) commonly seek help but often go unrecognized. Screening offers a means of identifying individuals for more detailed assessment for early intervention and for research. Aims: This study compared the McLean Screening Instrument for Borderline Personality Disorder (MSI-BPD), Borderline Personality Questionnaire (BPQ), the BPD items from the International Personality Disorder Examination Screening Questionnaire and the BPD items from the Structured Clinical Interview for DSM-IV Axis II disorders (SCID-II) Personality Questionnaire. Method: 101 outpatient youth (aged years) completed the screening measures and were interviewed, blind to screening status, with the SCID-II BPD module. The screening measures were readministered two weeks later to assess test-retest reliability. Results: All four instruments performed similarly but the BPQ had the best mix of characteristics, with moderate sensitivity (0.68), the highest specificity (0.90), high negative predictive value (0.91) and moderate positive predictive value (0.65). Compared to the other three instruments, the BPQ had the highest overall diagnostic accuracy (0.85), a substantially higher kappa (0.57) with the criterion diagnosis, the highest test-retest reliability (ICC = 0.92) and the highest internal consistency (α =0.92). The only clear difference to emerge in the Receiver Operator Curve (ROC) analysis was that the BPQ significantly outperformed the MSI (p = 0.05). Conclusion: Screening for BPD in outpatient youth is feasible but is not a replacement for clinical diagnosis. Borderline personality disorder (BPD) usually emerges during adolescence and is associated with serious morbidity, such as mood, anxiety, and substance use disorders, along with severe impairment of psychosocial func- From The ORYGEN Research Centre, Department of Psychiatry, University of Melbourne, Melbourne, Australia (A. M. C., M. J., D. D., E. M., H. P. Y.); ORYGEN Youth Health, Melbourne, Australia (A. M. C.); and The School of Behavioral Science, The University of Melbourne, Melbourne, Australia (D. R., H. J. J.). The authors thank all participants in this study and the staff of ORYGEN Youth Health. Thanks also to Dr. Louise McCutcheon for training and supervision of the diagnostic assessments. The ORYGEN Research Centre is supported by funding from the Colonial Foundation, Melbourne, Australia. Address correspondence to Dr Andrew M Chanen, ORYGEN Research Centre, Locked Bag 10, Parkville, Victoria, Australia 3052; achanen@unimelb.edu.au 353

2 354 CHANEN ET AL. tioning (Chanen, Jovev, & Jackson, 2007). A substantial body of evidence indicates that BPD diagnostic criteria are no less reliable, valid, and stable prior to age eighteen years than they are in adulthood (Chanen et al., 2004; Chanen, Jovev, & Jackson, 2007; Westen, Shedler, Durrett, Glass, & Martens, 2003). BPD affects 0.9% (Lewinsohn, Rohde, Seeley, & Klein, 1997) to 3% (Bernstein et al., 1993) of community-dwelling teenagers (similar to the prevalence in adults; Lenzenweger, Lane, Loranger, & Kessler, 2007) but this rises to 10.8% (Bernstein et al., 1993) to 14% (Chabrol, Montovany, Chouicha, Callahan, & Mullet, 2001) if lower symptom thresholds are used. In clinical samples, the limited data suggest a prevalence of 11% in adolescent outpatients (Chanen et al., 2004), 49% in adolescent inpatients (Grilo, Becker, Fehon, et al., 1996) and 42% in young adult inpatients (Grilo, Becker, Edell, & McGlashan, 1996). Adolescents and young adults with BPD commonly seek help (Chanen, Jovev, et al., 2007; Zanarini, Frankenburg, Khera, & Bleichmar, 2001). However, they often go unrecognized (Chanen, Jovev, et al., 2007), in part because personality disorder (PD) diagnosis is seen as controversial prior to age eighteen (Paris, 2003) and is often discouraged. Consequently, many clinicians lack training or experience in making PD diagnoses in this age group. However, BPD traits also show considerable flexibility and malleability in young people (Lenzenweger & Castro, 2005), making this a key period in which to intervene. We have previously concluded that the available evidence supports the development and evaluation of early intervention programs for BPD in youth (Chanen, McCutcheon, Jovev, Jackson, & McGorry, 2007). However, recognition of the disorder, especially in adolescent clinical services, presents a significant barrier to the development of such programs. The use of a screening measure offers a means of drawing clinicians attention to the diagnosis in young people and also a potentially efficient means of identifying individuals for more detailed assessment for early intervention programs and for research. Screening, however, is not a replacement for rigorous diagnosis. Screening usually involves a trade off between sensitivity (the true positive rate) and specificity (the true negative rate). For screening in outpatient youth, a desirable test would have high sensitivity and a high negative predictive value (NPV; probability that a negative test means the person does not have the condition). In other words, it would detect nearly all the true cases of BPD and when the test is negative, one could be confident that a person does not have BPD. However, one possible cost of this approach might be tolerating a low positive predictive value (PPV; high false positive rate). There are numerous interview and self-report screening tools for PDs (Morse & Pilkonis, 2007) but fewer specifically for BPD (Poreh et al., 2006). Some investigators have used BPD scales derived from the items in general screening measures for PDs (e.g., Patrick, Links, Van Reekum, & Mitton, 1995; Trull, 1995), while others have developed measures specifically for BPD (e.g., Leichsenring, 1999; Poreh et al., 2006; Zanarini et al., 2003).

3 SCREENING FOR BPD 355 Also, studies are not always directly comparable, as they have used various definitions of BPD for their criterion diagnosis, including different versions of the DSM, the ICD, and Kernberg s Borderline Personality Organization (Kernberg, 1986). Moreover, it is possible that these criterion diagnoses will also vary according to the instruments used to measure them. Of the instruments designed to measure DSM-IV BPD, the McLean Screening Instrument for Borderline Personality Disorder (MSI-BPD; Zanarini et al., 2003) and the Borderline Personality Questionnaire (BPQ; Poreh et al., 2006) have shown particular promise in screening for youth with DSM-IV BPD but neither has been evaluated in psychiatric outpatients. This report examines the performance of four candidate screening measures for BPD in a sample of outpatient youth (aged years), against a criterion diagnosis of Structured Clinical Interview for DSM-IV Axis II disorders (SCID-II; First, Gibbon, Spitzer, Williams, & Benjamin, 1997) BPD. METHOD PARTICIPANTS The study took place at ORYGEN Youth Health, the government-funded, youth (aged 15 24) mental health service for western metropolitan Melbourne, Australia. Exclusion criteria for the study included: (1) intellectual disability; (2) substance intoxication or withdrawal on the day of the procedure and (3) meeting criteria for ORYGEN s first episode psychosis service, the Early Psychosis Prevention and Intervention Centre (EPPIC; McGorry, Edwards, Mihalopoulos, Harrigan, & Jackson, 1996). Of 238 referrals to ORYGEN, 89 (37.4%) could not be located for research interview, 4 (1.7%) had moved away from the service, 24 (10.1%) refused to participate, 5 were not approached for clinical reasons (2.1%), and 1 (0.4%) was excluded for intellectual disability. After complete description of the study to the participants, written informed consent was obtained from 115 participants (48.3%) or from their parent or guardian, where appropriate. Fourteen participants (5.9% of referrals) could not be located subsequently, leaving 101 participants available for the analysis. Seventy-three (72.3%) participants were female. The mean age of the sample was 18.8 years (SD = 2.8; range 15 25). Twenty-two participants (21.8%) met DSM-IV criteria for BPD ( 5 BPD criteria). The most common Axis I diagnoses in the sample were mood disorders (n = 56), anxiety disorders (n = 52), substance dependence (n = 21) and eating disorders (n = 19). MEASURES Screening Measures. The MSI-BPD (Zanarini et al., 2003) is a ten-item screening measure specifically for BPD. The questions are based upon a subset of the questions that comprise the borderline module of the Diagnostic Interview for DSM-IV Personality Disorders (DIPD-IV; Zanarini,

4 356 CHANEN ET AL. Frankenburg, Sickel, & Yong, 1996). It includes eight items for each of the first eight DSM-IV criteria for BPD and two items for the ninth criterion of paranoia/dissociation. In a sample of adults with treatment histories responding to advertisements, the MSI-BPD had good sensitivity (0.81) and specificity (0.85) against a criterion diagnosis of DIPD BPD. Encouragingly, for the aims of the present study, in post hoc analyses of participants aged years, these figures rose to 0.9 (sensitivity) and 0.93 (specificity). Predictive values, accuracy and Cohen s Kappa are not reported by Zanarini and colleagues but can be calculated for the overall sample of 200 from the data provided (PPV 0.93; NPV 0.67; accuracy 0.83; kappa 0.62). Internal consistency of the MSI was found to be acceptable (α = 0.74). The BPQ (Poreh et al., 2006) is an 80-item true/false self-report measure comprising nine subscales corresponding to the nine DSM-IV BPD criteria. These are labeled impulsivity (9 items), affective instability (10 items), abandonment (10 items), unstable relationships (8 items), self-image (9 items), self-mutilation (7 items), emptiness (10 items), intense anger (10 items) and quasi-psychotic states (7 items). The BPQ s psychometric properties were established using four normal samples, with mean ages from years (SD = 2.91) to years (SD = 5.81). The BPQ has high internal consistency (Kuder-Richardson coefficient = 0.94) and convergent validity with the MMPI-2 BPD scale (r = 0.85), along with satisfactory criterion validity (tau = 0.51) using the Diagnostic Interview for Borderline Patients (Gunderson, Kolb, & Austin, 1981). In addition, the BPD items from the screening questionnaires for two other common semi-structured interviews for PD were chosen, the International Personality Disorder Examination Screener (IPDE-S; Loranger, 1999) and the Structured Clinical Interview for DSM-IV Axis II Personality Questionnaire (SCID-II PQ; First et al., 1997), the latter of which is matched to the SCID-II which was used as the criterion diagnosis for the present study. The IPDE-S contains nine BPD items (IPDE-BPD), corresponding to each of the nine DSM-IV BPD criteria, in a true/false response format. The SCID-II PQ contains fifteen BPD items (SCID-II PQ-BPD) in a yes/no response format, corresponding to the nine DSM-IV BPD criteria. Each DSM-IV criterion has one question, except for criteria three (identity disturbance, four questions), five (recurrent suicidal behavior, two questions) and eight (inappropriate anger, three questions). Psychometric data are not available for the IPDE-BPD or SCID-II PQ-BPD used as stand alone screening instruments. DIAGNOSTIC INTERVIEW Axis I diagnoses were obtained using the Structured Clinical Interview for DSM-IV axis I disorders-patient version (SCID-I/P; First, Gibbon, Spitzer, & Williams, 1996). The SCID-II is a 120-item semi-structured interview which assesses for

5 SCREENING FOR BPD 357 all DSM-IV PDs. In the present study, the BPD module was administered blind to screening status. In the SCID-II, each DSM-IV PD item is scored on a three-point scale (1 = absent, 2 = subthreshold or 3 = present). In common with previous literature (Bernstein, Cohen, Skodol, Bezirganian, & Brook, 1996), a PD feature was scored positive if it was present for two years and did not occur exclusively during an axis I disorder. This is one year longer than that required for adolescents in the DSM-IV. A score of three on at least five out of nine BPD items was required for a diagnosis of BPD. PROCEDURE The study was approved by the Northwestern Mental Health Research and Ethics Committee. After complete description of the study to the participants, written informed consent was obtained from participants or from a parent or guardian, where appropriate. All participants were remunerated AU$35 to cover expenses. Participants completed the first set of questionnaires and two semi-structured interviews (SCID-I/P and SCID-II). The self-report questionnaires were readministered to all participants two weeks after (mean duration = 13.7 days, SD = 15.5) their initial assessment. The order of presentation of questionnaires in each set were randomized using (Urbaniak, Plous, & Lestik, 2003). DATA ANALYSIS All data were analyzed using Statistical Package for the Social Sciences, Version 12.0 (SPSS 12.0) and S-PLUS 6.2 for Windows (Insightful Corporation, 2003). The test-retest reliability of the four self-report instruments was examined by looking at the agreement between time 1 (T1) and time 2 (T2) in terms of the individual items and the total score. For the individual items, the percentage of participants showing the same response at T1 and T2 was calculated for each instrument and appropriate summary statistics were computed. In terms of the total scores, Intraclass Correlation Coefficient (ICC) was used to measure the agreement between each instrument at T1 and at T2. The internal consistency for the self-report measures was computed using Cronbach s alpha reliability coefficient and the inter-item correlation was analyzed using Pearson s product moment correlation. The performance of each screening instrument was evaluated by computing the value of sensitivity, specificity, PPV, and NPV for that instrument. Receiver Operator Curve (ROC) analysis was used to obtain information regarding all possible pairs of achievable sensitivity and specificity values for each screening instrument. This analysis also determined the optimal cut-off score for each instrument to obtain the best value of sensitivity and specificity. The kappa statistic was also used as a measure of agreement between the criterion diagnosis and each of the screening instruments, employing Fleiss (1986) guidelines (poor agreement: <0.40, fair to good agreement: , excellent agreement: >0.75).

6 358 CHANEN ET AL. RESULTS COMPARING BPD SCREENING INSTRUMENTS WITH SCID-II CRITERION DIAGNOSIS Figure 1 shows a plot of the ROC curves of the four instruments based upon the total scores of each instrument. A ROC curve is a plot of the true positive rate (sensitivity) against the false positive rate (1-specificity) for all the possible cut-off points of an instrument. The optimal screening measure would have a true positive rate of 100% and a false positive rate of 0%, which would be indicated by a curve in the top left corner of the plot or as close to this point as possible. Figure 1 shows that the BPQ is completely above the SCID-II PQ and MSI and nearly completely above IPDE. The IPDE and MSI are quite close to each other with the IPDE being above the MSI for most of the plot. There is also a considerable crossover between the SCID-II-PQ and each of the IPDE and MSI. Statistical tests were carried out to test for the difference between the curves in terms of the area under the curves. The only significant comparison is that between BPQ and MSI (p = 0.05), which together with the results in Figure 1, indicate that the BPQ is significantly better than the MSI FIGURE 1. ROC curves for the four BPD screening instruments with the criterion diagnosis of SCID II BPD.

7 SCREENING FOR BPD 359 in terms of the overall diagnostic accuracy when all the possible cut-points of these two instruments are taken into account. In practice, however, only one cut-point would be used for each instrument. Thus another way of comparing the different instruments is to select the best cut-point of each instrument and evaluate its performance. Since the different points on a ROC curve represent trade-offs between the true positive rate and the false positive rate, the best cut-point depends on the relative importance of these two rates. One reasonable way to choose the best point is to select the point closest to the top left corner, as shown in Figure 1. The results for these best cut-points are shown in Table 1. Examination of kappa statistic suggests that most of the instruments show moderate agreement (kappa between 0.40 and 0.75) with the criterion diagnosis (SCID II), with the BPQ appearing to show the best agreement. Poor agreement (kappa <0.40) was obtained for the MSI. Thus, the results indicate that the BPQ is the best of the four screening measures tested in this study as, (1) its ROC curve is completely above or nearly completely above the other curves, (2) it has the highest specificity value, the highest PPV and the highest kappa value (Table 1) and (3) its sensitivity value and NPV are comparable to those of the other measures. TEST-RETEST RELIABILITY OF THE BPD SCREENING INSTRUMENTS This was examined by looking at the agreement between T1 and T2 in terms of individual items and in terms of the total score. In terms of individual items, the percentage of participants who showed agreement between the two occasions in their responses was calculated for each item. All of the four instruments had very similar percentages of participants giving the same response on both occasions, with approximately 85% of the participants showing agreement between the two occasions when averaged over the items within each instrument. In terms of the total scores, the ICC values were computed as a measure of agreement between the two occasions. Table 1 shows that the lowest ICC value was obtained for MSI, followed by IPDE, SCID-II PQ and BPQ, respectively. Both the average agreement of 85% and the high ICC values therefore suggest good testretest reliability for all four instruments, particularly the BPQ. INTERNAL CONSISTENCY OF THE BPD SCREENING INSTRUMENTS Cronbach s alpha coefficient was used as a measure of the internal consistency for the four BPD screening instruments (see Table 1). Using 0.70 as an acceptable value for the alpha coefficient (Nunnally, 1978), the majority of the other measures with the exception of IPDE, appear to have good internal consistency. Note that the alpha coefficient is related to the length of an instrument in the sense that a longer instrument will generally give a higher coefficient. So the alpha value of the BPQ is not directly comparable with those of the other measures.

8 TABLE 1. Best Cut-Points as Derived from Time 1 Data, Internal Consistency and Test-Retest Reliability Negative Positive Overall Number Best predictive predictive diagnostic Kappa Instrument of items cut-point Sensitivity Specificity value value accuracy (se) Alpha ICC 0.45 IPDE-BPD 9 > (0.09) 0.45 SCID-II PQ-BPD 15 > (0.10) 0.35 MSI 10 > (0.09) 0.57 BPQ 80 > (0.10) Note. ICC denotes intraclass correlation

9 SCREENING FOR BPD 361 DISCUSSION The main finding from this study is that all four instruments performed similarly, with moderate sensitivity, moderate to high specificity, high NPVs, low to moderate PPVs, moderate agreement with the criterion diagnosis (except the MSI), acceptable to high internal consistency (except the IPDE-BPD) and good test-retest reliability. However, there are noteworthy differences that might favor one instrument over another. The BPQ appears to have the best mix of characteristics, with moderate sensitivity, the highest specificity, high NPV and moderate PPV. It also has high internal consistency. Compared to the other three instruments, the BPQ has the highest overall diagnostic accuracy, a substantially higher kappa and the highest test-retest reliability. The only clear difference to emerge in the ROC analysis was that the BPQ significantly outperformed the MSI. The main drawback of the BPQ for screening purposes is its length, which might prove unacceptable to patients and to clinicians. However, the BPQ has a simple yes/no response format that can be completed by the patient in around ten minutes and scored by the clinician in five minutes. This investment in time might be worthwhile when BPD identification and treatment is a higher priority, such as in specialist BPD treatment or research programs. When BPD is but one of many priorities, such as in general clinical services, the SCID-II PQ-BPD might prove more suitable. For the MSI, the present study found that a slightly higher cut point (>7 compared to 7 in Zanarini and colleagues study) gave the best balance of sensitivity and specificity. In contrast to Zanarini and colleagues (2003) findings, we found only moderate sensitivity and specificity in our sample. We also found the opposite pattern of predictive values with a high NPV and low PPV, which better suits the intended purpose outlined in the introduction. Moreover, we found internal consistency was similar in both studies and test-retest reliability was good, although the lowest of the four instruments tested. The relatively poor performance of the MSI might have been due to the choice of the SCID-II as the criterion diagnosis. In Zanarini and colleagues study, the criterion was the DIPD and the MSI questions are tightly linked to this instrument. The slightly superior performance of the SCID-II PQ- BPD, compared to the MSI, might reflect its tight linkage to the questions in the SCID-II criterion diagnosis. There are subtle but important differences between the SCID-II and DIPD in their operational definitions of the DSM-IV BPD criteria. For example, angry outbursts are only assessed under the inappropriate anger criterion in the SCID-II, whereas in the DIPD, they contribute to the scoring of both the impulsivity and inappropriate anger items. Another source of differences between the present study and that of Zanarini and colleagues is the sample itself. Zanarini and colleagues advertised for participants and selected those with treatment histories. In the present study, the sample was derived from acute referrals to a frontline

10 362 CHANEN ET AL. youth mental health service. Zanarini and colleagues report that 69.5% of participants met criteria for BPD, compared to 21.8% in the present study. Zanarini and colleagues prevalence is higher than base rates reported for most acute clinical services, including adolescent (Grilo, Becker, Fehon, et al., 1996), young adult (Grilo, Becker, Edell, et al., 1996) and adult (Widiger & Weissman, 1991) inpatient units. The performance of a screening measure will vary according to the base rate of the diagnosis in question (Morse & Pilkonis, 2007). For a fixed test sensitivity and specificity, the rarer the disorder, the lower the PPV of the test and this is the most likely explanation for the high PPV in Zanarini and colleagues study and the low PPV in the present study. The main strength of the present study is its use of actual outpatients in a setting in which the screening measure will be used. However, we can only comment to a limited extent upon the representativeness of the sample. We have previously found that the presence and number of Axis I and II disorders in adolescent outpatients is significantly associated with follow-up contact difficulty and might lead to underestimation of the extent of psychopathology in a sample (Allott, Chanen, & Yuen, 2006). Another limitation includes the requirement that participants complete all screening measures (presented in random order) in one sitting. Therefore, the findings might not reflect the performance of each measure when administered individually. Also, the IPDE-BPD and SCID-II PQ-BPD were actually subsets of items extracted from the corresponding original instruments. It is unclear whether they would perform the same when administered in their complete form. Another limitation is that the criterion diagnosis was a semi-structured interview by a trained research assistant. It was neither an expert clinical diagnosis nor a diagnosis using the Longitudinal Expert All Data (LEAD; Pilkonis, Heape, Ruddy, & Serrao, 1991) standard. Moreover, the use of a categorical diagnosis of BPD means that criterion negative participants might have had sub-syndromal BPD or other personality pathology. In fact, a further 8 participants met 4 SCID-II BPD criteria and a further ten met 3 SCID-II BPD criteria. The present findings indicate that screening for BPD in outpatient youth is feasible and should help improve recognition of the disorder among clinicians. Based upon our findings the BPQ achieves the best balance of the desired properties in a screening instrument. However, its length is a significant drawback and might preclude more widespread clinical application. Of the shorter instruments, the data favor the SCID-II BPD but this might be dependent upon the choice of criterion diagnosis. REFERENCES Allott, K., Chanen, A., & Yuen, H. P. (2006). Attrition bias in longitudinal research involving adolescent psychiatric out- patients. Journal of Nervous and Mental Disease, 194, Bernstein, D. P., Cohen, P., Skodol, A., Bezir-

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