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Research Article                                                                                                                                        Open Access

## Psychometric Qualities of the Dimensional Assessment of Personality Pathology - Short Form for Adolescents

Noor B. Tromp 1* , Hans M. Koot 2

1 Triversum, Center for Child and Adolescent Psychiatry, The Netherlands 2 VU University Amsterdam, The Netherlands

*Corresponding author: ntromp@triversum.nl

## Abstract

Background: A  growing  body  of  research  recognizes  the  occurrence  and  validity  of  personality  pathology  during adolescence as well as its relevance as a developmental precursor of adult personality pathology.

Objective: The present study recognizes the need for a comprehensive and concise instrument to assess the dimensions of personality pathology in adolescents. Therefore, the psychometric qualities of an abbreviated version of the Dimensional Assessment of Personality Pathology - Basic Questionnaire for Adolescents (DAPP-BQ-A), which has been denoted as the DAPP - Short Form for Adolescents (DAPP-SF-A), were examined.

Method: The factorial structure, internal consistency, test-retest reliability, discriminative validity, and classification accuracy of  the  DAPP-SF-A  scales  were  examined  in  three  samples:  1596  non-referred  adolescents;  166  adolescents  referred  to inpatient and outpatient mental health services; and 58 referred and general population adolescents.

Results: Despite a reduction in the number of items by 50% (from 290 to 144 items), the promising psychometric qualities established for the DAPP-BQ-A were replicated for the DAPP-SF-A.

Conclusions: The  results  of  this  study  are  promising  regarding  the  qualities  of  the  DAPP-SF-A  and  its  utility  in  both clinical and research settings. In addition, the equivalence of the instruments for adolescents and (young) adults enables the investigation of developmental trajectories across different life stages.

Keywords:

DAPP-SF-A; personality pathology; psychometrics; adolescents; short form

## Introduction

The future assessment of personality disorders (PDs) is a topic that has been frequently discussed in the recent literature (1-3). The categorical classification  system  as  a  diagnostic  tool  for  PDs was  retained  in  Section  II  of  the Diagnostic  and Statistical  Manual  of  Mental  Disorders,  Fifth  Edition (DSM-5) (4), despite its substantial and  widely recognized limitations (5-7). The growing consensus among the many alternative dimensional models of PD classification (8,9) may have contributed to the description of a hybrid model that combines categorical  and  dimensional  systems  in  Section  III of the DSM-5.

The Dimensional Assessment of Personality Pathology  -  Basic  Questionnaire  (DAPP-BQ;  10) can be used to assess dimensional personality traits such as those described in Section III of the DSM5.  The  DAPP-BQ is a hierarchical instrument that assesses affective, cognitive, and interpersonal characteristics important to a person's mental health,  adjustment, and well-being. It assesses four higher-order  dimensions  of  personality  pathology (i.e.,  Emotional  Dysregulation,  Dissocial  Behavior, Inhibitedness, and  Compulsivity) as well as 18 lower-order  dimensions  (e.g.,  Affective  Instability, Identity Problems, Callousness, Restricted Expression). These dimensions bear close conceptual  resemblance  to  the  traits  described  in Section III of the DSM-5. Moreover, a joint factor analysis showed  empirical convergence between components of the DAPP-BQ  and the four dimensions of the Personality Inventory for DSM-5 (11),  an  instrument  used  to  assess the  DSM-5 trait model  (12).  Evidence  for  the  strong  psychometric qualities  and  clinical  validity  of  the  DAPP-BQ  is well established (13-20).

A growing body of research recognizes the occurrence  and  validity  of  personality  pathology during  adolescence  as  well  as  its  relevance  as  a developmental precursor of adult personality pathology  (21,22).  Although  clinicians  have  often been  reluctant  to  apply  PD  diagnoses  to  younger age  groups,  both  the International Classification of Diseases and  the  DSM-5  allow  for  PD  diagnoses during adolescence (4,23). Until recently, there was no  widely  accepted,  reliable,  and  valid  instrument for the assessment of the broad range of personality pathology  dimensions  in  adolescents.  The  DAPPBQ  was  therefore  translated  and  adapted  for  use with  adolescents  (24).  The  resulting  DAPP  -  Basic Questionnaire  for  Adolescents  (DAPP-BQ-A)  is highly similar to its adult predecessor in terms of its concepts and design. The few adaptations that were made were aimed at ensuring age-appropriate assessment  and  consisted  mostly  of  simplifications of  language.  Details  describing  the  translation  and adaptation  procedures  were  presented  previously (24).  The  DAPP-BQ-A  has  been  found  to  assess dimensions of personality pathology in both referred  and  non-referred  adolescents  in  a  reliable and valid manner (24). In short, its factorial structure  is  highly  similar  to  that  reported  for  the adult DAPP-BQ (10); its median Cronbach's alphas were high; its average test-retest reliability was good; and several dimensions showed considerable promise for differentiating among non-referred adolescents, referred adolescents without PDs, and referred  adolescents  with  PDs  (24).  Moreover,  its dimensions have demonstrated significant, substantial, and conceptually meaningful relationships with interview-based PD symptoms as described  in  the  DSM-IV  as  well  as  with  the  Big Five dimensions of normal personality (25,26).

However,  despite the promising  psychometric properties of the DAPP-BQ-A, its clinical utility is threatened by a major disadvantage. The self-report questionnaire comprises 290 items and takes approximately 50 to 60 minutes to complete. Resistance to this long format (especially when it is used  for  repeated  assessments)  as  well  as  possible fatigue  due  to  its  length  may  hamper  its  use  with adolescents.  A  similar  problem  occurs  when  using alternative dimensional measures to assess adolescent personality pathology. For example, although a recent study provides preliminary evidence for the psychometric quality and construct validity  of  the  Personality  Inventory  for  DSM-5  in adolescents (27), the instrument, which contains 220 items,  is  quite  lengthy.  Thus,  the  assessment  of personality pathology dimensions  in adolescents may be benefitted by the development of shortened versions of established measures.

Because  the  need  for  a  dimensional  instrument that is both comprehensive and concise was recognized,  a  short  form  of  the  DAPP-BQ  was recently developed for adults (28-30). The resulting DAPP - Short Form (DAPP-SF) consists of 136 of the  original  290  items,  a  reduction  of  more  than 50%. During the process of shortening the questionnaire  as  described  by  Van  Kampen  and colleagues (30), the authors took into account several  possible  methodological  problems  (31)  and tackled  these  adequately.  The  most  defining  items were identified through principal components analyses of the items within each scale. The number of items selected per scale depended on the Cronbach's alpha coefficients of the original DAPPBQ scales as found for a Dutch general population sample (32): for scales with alpha coefficients between  .70  and  .79,  ten  items  were  selected;  for scales  with  alpha  coefficients  between  .80  and  .89, eight items were selected; and for scales with alpha coefficients of .90 or more, six items were selected. If the alpha coefficient of the shortened scales was less than .75, two items with the next highest factor saturations were added. In addition, the content of the items was taken into consideration. Items with similar  wording  were  discarded  and  replaced  by scale items with the next highest loadings representing different content. Each adjustment was followed  by  calculating  the  alpha  coefficient  to ensure that the internal consistency of the shortened scales would be at least .75.

Reports  about  the  DAPP-SF  for  adults  have yielded support for its adequate psychometric qualities (28-30). The  factorial structure of the DAPP-SF  proved  almost  identical  to  the  factor structure of the full-length DAPP-BQ, and this was demonstrated to be stable across various patient and community samples. In addition, indices for convergent, discriminant, and criterion-related validity  were  satisfactory  (28,29).  Given  the  good psychometric  characteristics  of  the  DAPP-SF  for adults, it was decided that the same items would be selected for the DAPP -Short Form for Adolescents (DAPP-SF-A).

Selecting the same items for the adolescent version as for the adult version has a clear advantage. Despite small differences in the wording of the items, it enables the comparison of personality  pathology  dimensions  across  different developmental  stages.  The  DAPP-SF-A  and  the DAPP-SF would therefore be suitable as subsequent instruments in longitudinal research that includes  both  adolescents  and  (young)  adults.  This may enhance studies of the similarities and dissimilarities  in  personality  pathology  across  ages, both in terms of structure and level.

The aim of the present study was to examine the psychometric properties of the DAPP-SF-A among non-referred  adolescents  and  adolescents  referred for inpatient and outpatient mental health services. More  specifically,  the  factorial  structure,  internal consistency, test-retest reliability, discriminative validity,  and  classification  accuracy  of  the  DAPPSF-A  scales  were  examined.  It  was  hypothesized that the psychometric properties of the abbreviated version were comparable to those of the full-length DAPP-BQ-A (24).

## Methods

## Participants and Procedures

Results were obtained from three different samples. Sample  1  consisted  of  non-referred  adolescents recruited  from  a  public  school  that  represented  all levels  of  Dutch  secondary  education.  This  sample consisted  of  1596  adolescents  (51%  male)  with  a mean age of 14.6 years (standard deviation [ SD ]  = 1.7; range 11 to 20 years). Sample 2 consisted of 166 adolescents  (35%  male)  with  a  mean  age  of  15.9 years  ( SD =  2.3;  range  12  to  22  years)  who  were referred  to  inpatient  or  outpatient  mental  health care  for  a  wide  range  of  psychopathology  and  not specifically for personality pathology. However, 42.2% of Sample 2 met the criteria of at least one PD.  The  most  prevalent  were  depressive  (19.9%), borderline (16.9%), and avoidant PD  (15.1%). Sample 3, which was the test-retest sample, consisted of 22 adolescents from Sample 2 and 36 adolescents from the general population who were recruited by a master's level student. The mean age of Sample 3 (26% male) was 18.7 years ( SD = 2.9; range 13 to 23 years).

More detailed information about the samples and the  sampling  procedures  (e.g.,  informed  consent) was presented in an earlier article that described the psychometric qualities  of  the  DAPP-BQ-A  for virtually the same three samples (24). As compared with  this  earlier  paper,  small  differences  in  the sample  characteristics  occurred  as  a  result  of  the imputation procedures of missing items and because adolescents for whom age or PD status (in Sample 2)  was  missing  were  excluded  from  all  analyses presented in the current study.

## Measures

Dimensional  Assessment  of  Personality  Pathology  -  Short Form for Adolescents. To arrive at the full-length, 290item DAPP-BQ-A, the items of its adult predecessor  (10)  were  translated  and  adapted  with the use of procedures similar to those described by Varni  and  colleagues  (33).  The  items  were  first translated  into  Dutch,  with  effort  made  to  stay  as close  to  the  original  text  and  meaning  as  possible. Next, the items and instructions that were considered too difficult  by pilot study respondents were  simplified.  In  addition,  a  'Not  applicable' option was added to the Likert-type scale for items that addressed sex, drug use, and alcohol use. After pilot testing, items were translated back into English and approved by the author of the original version (24).  To  arrive  at  the  abbreviated  version  of  the DAPP-BQ-A, the same 136 items that were selected for  the  DAPP-SF (30) were included. The 8 items from  the  DAPP-BQ-A  validity  scale  were  added, resulting in a total of 144 items, which are scored on a Likert-type scale that ranges from 1 ('Very unlike me' or 'Not applicable') to 5 ('Very like me'). The allocation of items to the lower-order dimensions in the  DAPP-SF-A  was  identical  to  the  allocation  of items in the DAPP-SF. Six lower-order dimensions are  composed  of  6  items,  10  are  composed  of  8 items, and 2 are composed of 10 items (Table 1).

Structured Clinical Interview for DSM-IV  Personality Disorders . To assess the DSM-IV personality disorder symptoms in Sample 2, the Dutch version (34) of the Structured Clinical Interview for DSMIV Personality Disorders (35) was administered by one of two trained research psychologists, who were blinded  to  the  adolescents'  DAPP-SF-A  scores, during  a  separate  interview  session  within  the  first month after referral. Similar diagnostic thresholds as those used for adults were used to assign adolescents to subsamples on the basis of their PD status.  For  the  purpose  of  the  present  analyses, categorical diagnoses were used.

## Statistical Analyses

Statistical  procedures  examining  the  psychometric qualities  of  the  DAPP-SF-A  were  similar  to  those followed in a previous report about the psychometric  qualities  of  the  DAPP-BQ-A  (24). First,  missing  DAPP-SF-A  items  (up  to  five  per participant, with a maximum of one within a lowerorder dimension) were imputed  with estimated values using the expectation-maximization method. Across  all  three  samples,  for  613  participants,  one or  more  items  were  imputed.  Second,  to  evaluate the factorial structure, a principal components analysis  (PCA)  followed  by  oblimin  rotation  was performed on the original 18 lower-order dimensions for a combined sample of non-referred (Sample  1)  and  referred  (Sample  2)  adolescents.  A parallel analysis (36) was subsequently performed to determine  the  number of factors to  be  retained  in the  PCA.  To  interpret  the  substantive  importance of  a  lower-order  dimension  to  a  factor,  factor loadings with a value of .40 or higher were retained (15,37).

Subsequently,  Cronbach's  alpha  coefficients  for the lower-order dimensions were calculated separately  for  Samples  1  and  2.  To  assess  3-week test-retest reliabilities, intraclass correlation coefficients for absolute agreement were computed in  a  two-way  random  effects  model  for  Sample  3. To examine the discriminative validity of the DAPP-SF-A dimensions, all adolescents in Samples 1 and 2 were assigned to one of three subsamples: non-referred adolescents (Sample 1), referred adolescents  without  a  PD  (Subsample  2a),  and referred  adolescents  with  a  PD  (Subsample  2b). Next, two multivariate analyses of covariance were conducted on the 18 lower-order and 4 higher-order dimensions,  respectively,  with  sample  membership and  gender  as  independent  variables  and  age  as  a covariate.  For  each  separate  dimension,  univariate analyses  of  variance  were  conducted  as  follow  up, and  post-hoc  analyses  with  Bonferroni  corrections were used to test the significance of the differences among the three subsamples. Finally, receiver operating  characteristic  (ROC)  analyses  were  used to examine the ability of the DAPP-SF-A dimensions to distinguish among samples.

## Results

Factor Structure

The factor structure of the DAPP-SF-A was examined in the combined  sample of referred (Sample 2) and non-referred (Sample 1) adolescents with  the  use  of  PCA  (see  Table  1).  According  to Kaiser's  criterion  (i.e.,  eigenvalues  >  1),  the  PCA suggested a four-factor solution, with eigenvalues of 7.277, 2.531, 1.427, and 1.004 for Emotional Dysregulation, Dissocial Behavior, Inhibitedness, and Compulsivity, respectively. This solution explained  68.0%  of  the  total  variance,  which  was similar to the solution found for the DAPP-BQ-A. Parallel  Analysis  suggested  to  retain  the  first  three factors.  The  majority  of  lower-order  dimensions loaded  predominantly  on  their  purported  factors. One  exception was the lower-order dimension Restricted Expression, which loaded predominantly on Emotional Dysregulation instead of on Inhibitedness.  However,  this  result  was  not  found for the DAPP-BQ-A. In addition, the PCA with the DAPP-SF-A  dimensions  did  not  result  in  crossloadings of .40 or higher as it did with the DAPPBQ-A  dimensions.  The  Narcissism  dimension  of the  DAPP-SF-A  showed  a  clear  loading  on  the factor  Dissocial  Behavior.  This  was  different  from the  Narcissism  dimension  of  the  DAPP-BQ-A, which  showed  a  more  diffuse  pattern of high loadings on three of the four factors.

## Internal Consistency

The  internal consistency coefficients of the 18 lower-order dimensions for Sample 1 and Sample 2 are  presented  separately  in  Table  1.  The  internal consistency  reliabilities  ranged  from  .78  to  .93  in Sample  2  (median,  .85)  and  from  .66  to  .86  in Sample  1  (median,  .80).  These  were  similar  to  the values found for the DAPP-BQ-A in these samples (.88 and .86, respectively).

## Test-Retest Reliability

The test-retest reliabilities are presented in the final column of Table 1. The interval period ranged from 16  to  31  days,  with  a  mean  of  22  days  ( SD =  3). Intraclass correlation coefficients were significant ( p < .05) for all scales ( M = .82). However, like that of the DAPP-BQ-A, the intraclass correlation coefficient for Intimacy Problems was relatively low (.20).

## Discriminative Validity

Mean sample differences of the DAPP-SF-A higher-order and lower-order dimensions were examined between non-referred adolescents (Sample  1), referred adolescents  without  a  PD (Subsample 2a), and referred adolescents with a PD (Subsample  2b).  Table  2  presents  the  means  and standard deviations of the lower-order and higherorder dimensions for the three samples. As a result of the large size of Sample 1, a significance level of .01  was  adhered  to  for  the  reporting  of  significant results. The overall effect of the multivariate analysis of covariance testing for sample effects was significant  for  both  the  lower-order  dimensions (Wilk's λ = 0.57; F (36, 3480) = 31.0; p < .001) and the  higher-order  dimensions  (Wilk's  λ  =  0.79; F (8, 3508)  =  55.4; p <  .001).  One-way  analyses  of variance  conducted  as  a  means  of  follow  up  were statistically significant for all lower-order and higher-order  dimensions,  except  for  lower-order Rejection ( p = .024) and higher-order Inhibitedness ( p = .011).

Table  2  also  presents  effect  sizes  as  represented by partial  eta-squared  for  gender,  age,  and  sample. Significant gender effects were found for all but five lower-order  dimensions  and  all  but  one  higherorder  dimension.  Although  they  were  significant, effects were small in terms of Cohen's criteria (38) for  all  but  four  dimensions;  there  were  medium effects  for  Affective  Instability  (higher  score  for girls),  Callousness,  and  Dissocial  Behavior  and  a large effect for Conduct Problems (all higher scores for  boys).  All  significant  age  effects,  except  for Insecure Attachment, indicated an age-related increase  in  scores,  although  effects  were  small  or For each dimension, the highest loadings appear in bold text.

TABLE  1. Oblimin-Rotated  Principal  Component  Factor  Loadings  for  Four-Factor  Structure  (Samples  1  and  2,  N  =  1762), Internal  Consistency  (Cronbach's  α;  Sample  2  [N  =  166]  and  Sample  1  [N  =  1596]),  and  Test-Retest  Reliability  (Intraclass Correlation Coefficients; Sample 3 [N = 58]) for the Lower-Order Dimensions of the Dimensional Assessment of Personality Pathology - Short Form for Adolescents

|                           |   Factor loadings for four-factor structure |   Factor loadings for four-factor structure |   Factor loadings for four-factor structure |   Factor loadings for four-factor structure | Internal consistency   | Internal consistency   |   Test-retest reliability |
|---------------------------|---------------------------------------------|---------------------------------------------|---------------------------------------------|---------------------------------------------|------------------------|------------------------|---------------------------|
|                           |                                           1 |                                           2 |                                           3 |                                           4 | Sample 2               | Sample 1               |                           |
| Dimension (no. of items)  |                                             |                                             |                                             |                                             |                        |                        |                           |
| Submissiveness (8)        |                                         .80 |                                        -.10 |                                         .06 |                                        -.12 | .87                    | .78                    |                       .79 |
| Cognitive Distortion (6)  |                                         .79 |                                         .06 |                                         .07 |                                         .01 | .84                    | .78                    |                       .82 |
| Identity Problems (6)     |                                         .89 |                                         .00 |                                        -.08 |                                         .05 | .87                    | .80                    |                       .89 |
| Affective Instability (8) |                                         .85 |                                        -.00 |                                         .19 |                                        -.00 | .88                    | .82                    |                       .91 |
| Oppositionality (10)      |                                         .52 |                                         .37 |                                         .23 |                                         .28 | .84                    | .81                    |                       .85 |
| Anxiety (6)               |                                         .87 |                                        -.07 |                                         .06 |                                        -.08 | .90                    | .83                    |                       .84 |
| Social Avoidance (6)      |                                         .84 |                                        -.09 |                                        -.08 |                                        -.11 | .86                    | .79                    |                       .90 |
| Suspiciousness (8)        |                                         .69 |                                         .23 |                                        -.19 |                                        -.12 | .87                    | .76                    |                       .87 |
| Insecure Attachment (6)   |                                         .64 |                                        -.06 |                                         .38 |                                        -.08 | .87                    | .80                    |                       .85 |
| Narcissism (8)            |                                         .21 |                                         .56 |                                         .23 |                                        -.38 | .80                    | .80                    |                       .87 |
| Self-Harm (6)             |                                         .70 |                                         .03 |                                        -.24 |                                         .19 | .93                    | .86                    |                       .91 |
| Stimulus Seeking (8)      |                                         .07 |                                         .68 |                                         .12 |                                         .36 | .85                    | .82                    |                       .88 |
| Callousness (10)          |                                         .01 |                                         .86 |                                        -.06 |                                        -.09 | .85                    | .81                    |                       .83 |
| Rejection (8)             |                                        -.14 |                                         .82 |                                         .07 |                                        -.30 | .82                    | .77                    |                       .75 |
| Conduct Problems (8)      |                                         .05 |                                         .75 |                                        -.16 |                                         .28 | .81                    | .80                    |                       .93 |
| Restricted Expression (8) |                                         .64 |                                         .11 |                                        -.27 |                                        -.04 | .79                    | .79                    |                       .84 |
| Intimacy Problems (8)     |                                        -.08 |                                         .04 |                                         .86 |                                         .04 | .78                    | .66                    |                       .20 |
| Compulsivity (8)          |                                         .22 |                                         .05 |                                        -.02 |                                         .80 | .83                    | .80                    |                       .86 |
| Explained Variance        |                                        40.4 |                                        14.1 |                                         7.9 |                                         5.6 |                        |                        |                           |

All intraclass correlation coefficients are significant at p < .001, except for Intimacy Problems ( p < .05)

TABLE 2. Mean Scores and Standard Deviations on Dimensional Assessment of Personality Pathology - Short Form for Adolescents Dimensions for Non-Referred Adolescents  (Sample  1,  N  =  1596),  Referred  Adolescents  Without  Personality  Disorders  (Subsample  2a,  n  =  96),  and  Referred  Adolescents  With  Personality Disorders (Subsample 2b, n = 70), and Effect Sizes (Partial Eta-Squared) for Gender, Age, and Sample With Contrasts

|                         | Sample 1   | Sample 1   | Subsample 2a   | Subsample 2a   | Subsample 2b   | Subsample 2b   | Effect Sizes   | Effect Sizes   | Effect Sizes   | Contrasts*    |
|-------------------------|------------|------------|----------------|----------------|----------------|----------------|----------------|----------------|----------------|---------------|
| Dimension               | Mean       | SD         | Mean           | SD             | Mean           | SD             | Gender         | Age            | Sample         | Contrasts*    |
| Emotional Dysregulation | 157.9      | 39.0       | 195.1          | 51.7           | 248.6          | 56.2           | .019 G         | ns             | .166           | 1 < 2a < 2b   |
| Submissiveness          | 15.9       | 5.0        | 19.5           | 6.6            | 22.9           | 8.2            | .025 G         | ns             | .066           | 1 < 2a < 2b   |
| Cognitive Distortion    | 11.0       | 4.3        | 13.1           | 5.2            | 17.5           | 6.2            | .016 G         | ns             | .078           | 1 < 2a < 2b   |
| Identity Problems       | 10.7       | 4.3        | 15.4           | 6.2            | 20.6           | 6.6            | .015 G         | ns             | .176           | 1 < 2a < 2b   |
| Affective Instability   | 18.1       | 6.1        | 23.9           | 7.9            | 30.0           | 7.0            | .071 G         | ns             | .134           | 1 < 2a < 2b   |
| Oppositionality         | 25.1       | 7.1        | 28.0           | 8.4            | 32.6           | 8.1            | ns             | .024           | .034           | (1 = 2a) < 2b |
| Anxiety                 | 12.2       | 4.8        | 17.0           | 6.7            | 21.1           | 6.7            | .040 G         | .006           | .119           | 1 < 2a < 2b   |
| Social Avoidance        | 11.5       | 4.3        | 15.2           | 6.0            | 19.8           | 6.0            | .012 G         | ns             | .123           | 1 < 2a < 2b   |
| Suspiciousness          | 14.7       | 4.5        | 17.1           | 6.0            | 24.4           | 7.6            | ns             | ns             | .146           | 1 < 2a < 2b   |
| Insecure Attachment     | 12.7       | 4.7        | 15.8           | 6.1            | 18.7           | 6.8            | .047 G         | .004           | .066           | 1 < 2a < 2b   |
| Narcissism              | 18.6       | 5.7        | 19.0           | 5.8            | 21.5           | 7.3            | ns             | .011           | .007           | 1 < 2b        |
| Self-Harm               | 7.4        | 3.1        | 11.0           | 6.4            | 19.5           | 8.2            | ns             | ns             | .303           | 1 < 2a < 2b   |
| Dissocial Behavior      | 77.0       | 19.4       | 73.6           | 16.3           | 91.6           | 24.8           | .131 B         | .026           | .028           | (1 = 2a) < 2b |
| Stimulus Seeking        | 21.4       | 6.5        | 20.3           | 6.8            | 26.1           | 8.1            | .048 B         | .004           | .023           | (1 = 2a) < 2b |
| Callousness             | 20.7       | 6.4        | 18.7           | 6.3            | 23.1           | 8.9            | .097 B         | .015           | .013           | 2a < 1 < 2b   |
| Rejection               | 20.9       | 5.7        | 21.6           | 5.8            | 22.9           | 7.8            | .050 B         | .021           | ns             | 1 = 2a = 2b   |
| Conduct Problems        | 14.0       | 5.7        | 13.1           | 5.0            | 19.4           | 7.6            | .158 B         | .029           | .044           | (1 = 2a) < 2b |
| Inhibitedness           | 45.2       | 7.3        | 44.9           | 9.5            | 48.2           | 10.8           | ns             | ns             | ns             | 1 = 2a = 2b   |
| Restricted Expression   | 18.4       | 5.6        | 23.3           | 6.6            | 27.1           | 6.2            | ns             | ns             | .104           | 1 < 2a < 2b   |
| Intimacy Problems       | 26.9       | 4.9        | 21.6           | 6.5            | 21.2           | 7.5            | .011 G         | ns             | .093           | 1 > (2a = 2b) |
| Compulsivity            | 18.4       | 5.7        | 19.7           | 6.3            | 20.5           | 7.0            | .005 G         | ns             | .006           | 1 = 2a = 2b   |

Lower-order Compulsivity was omitted because it is identical to higher-order Compulsivity

All significant age effects, except for Insecure Attachment, reflected higher scores for older adolescents ( p < .01)

TABLE  3 . Area  Under  the  Receiver  Operating  Characteristic  Curve  for  Dimensional  Assessment  of Personality Pathology - Short Form for Adolescents Dimensions for Non-referred Adolescents (Sample 1, N = 1596),  Referred  Adolescents  (Sample  2,  N  =  166),  Referred  Adolescents  Without  Personality  Disorders (Subsample 2a, n = 96), and Referred Adolescents With Personality Disorders (Subsample 2b, n = 70)

|                         | Sample 1 vs. Sample 2   | Sample 1 vs. Sample 2   | Sample 1 vs. Subsample 2b   | Sample 1 vs. Subsample 2b   | Subsample 2a vs. Subsample 2b   | Subsample 2a vs. Subsample 2b   |
|-------------------------|-------------------------|-------------------------|-----------------------------|-----------------------------|---------------------------------|---------------------------------|
| Dimension               | AUC                     | 95% CI                  | AUC                         | 95% CI                      | AUC                             | 95% CI                          |
| Emotional Dysregulation | .79*                    | .74-.83                 | .89*                        | .84-.94                     | .77*                            | .69-.84                         |
| Submissiveness          | .70*                    | .66-.76                 | .76*                        | .69-.83                     | .62*                            | .53-.71                         |
| Cognitive Distortion    | .69*                    | .65-.74                 | .79*                        | .73-.86                     | .71*                            | .62-.79                         |
| Identity Problems       | .79*                    | .75-.83                 | .88*                        | .82-.93                     | .72*                            | .64-.80                         |
| Affective Instability   | .79*                    | .75-.83                 | .89*                        | .85-.93                     | .72*                            | .64-.79                         |
| Oppositionality         | .67*                    | .62-.72                 | .77*                        | .70-.83                     | .66*                            | .58-.75                         |
| Anxiety                 | .77*                    | .72-.81                 | .85*                        | .79-.90                     | .67*                            | .59-.76                         |
| Social Avoidance        | .76*                    | .71-.80                 | .86*                        | .81-.91                     | .70*                            | .62-.78                         |
| Suspiciousness          | .72*                    | .67.-76                 | .85*                        | .80-.91                     | .77*                            | .70-.84                         |
| Insecure Attachment     | .69*                    | .64-.74                 | .76*                        | .69-.82                     | .63*                            | .54-.71                         |
| Narcissism              | .56*                    | .52-.61                 | .62*                        | .55-.69                     | .59                             | .51-.68                         |
| Self-Harm               | .76*                    | .71-.81                 | .88*                        | .82-.93                     | .78*                            | .70-.85                         |
| Dissocial Behavior      | .55                     | .50-.59                 | .68*                        | .61-.75                     | .73*                            | ..64-.81                        |
| Stimulus Seeking        | .54                     | .49-.59                 | .67*                        | .60-.74                     | .71*                            | .63-.79                         |
| Callousness             | .47                     | .43-.52                 | .57                         | .50-.65                     | .66*                            | .57-.74                         |
| Rejection               | .55                     | .50-.60                 | .58                         | .49-.66                     | .55                             | .46-.64                         |
| Conduct Problems        | .57*                    | .52-.61                 | .72*                        | .66-.78                     | .76*                            | .69-.84                         |
| Inhibitedness           | .54                     | .49-.59                 | .58                         | .50-.67                     | .58                             | .49-.67                         |
| Restricted Expression   | .78*                    | .74-.82                 | .85*                        | .80-.90                     | .67*                            | .58-.75                         |
| Intimacy Problems       | .27                     | .22-.31                 | .25                         | .18-.33                     | .47                             | .38-.56                         |
| Compulsivity            | .58*                    | .53-.62                 | .59                         | .52-.66                     | .52                             | .43-.61                         |

AUC, Area under the curve; CI, confidence interval

* p < .01

Lower-order Compulsivity was omitted because it is identical to higher-order Compulsivity

negligible in terms of Cohen's criteria. Gender and age  effects  were  very  similar  to  those  reported  for the DAPP-BQ-A. Significant overall sample effects were  found  for  all  but  one  lower-order  dimension and  all  but  one  higher-order  dimension.  The  final column  in  Table  2,  which  is  labeled  'Contrasts', shows the results of post-hoc analyses with Bonferroni  corrections  when  controlling  for  age. For the majority of dimensions, referred adolescents with  a  PD  (Subsample  2b)  received  the  highest scores,  and  non-referred  adolescents  (Sample  1) received  the  lowest  scores  ( p <  .01).  In  terms  of Cohen's  criteria,  large  effects  (>  .138)  were  found for  Emotional  Dysregulation,  Identity  Problems, Self-Harm, and Suspiciousness.

## Classification Accuracy

Table 3 shows the area under the receiver operating characteristic curve with accompanying 95% confidence intervals. Similar to the results obtained for  the  DAPP-BQ-A,  Dissocial  Behavior  and  its constituent  lower-order  dimensions  did  not  show significant  accuracy  for  the  discrimination  between non-referred  adolescents  (Sample  1)  and  referred adolescents  (Sample  2).  Unlike  the  results  of  the DAPP-BQ-A, Inhibitedness and Intimacy Problems also  did  not  demonstrate  significant  accuracy.  All other  dimensions  showed  significant  accuracy  ( p < .01) for discrimination between Samples 1 and 2. Eight of the lower-order dimensions showed fair to good  accuracy  (≥.70),  with  Identity  Problems  and Affective Instability performing particularly well

(both  were  .79).  For  distinguishing  between  nonreferred adolescents (Sample 1) and referred adolescents  with  PD  (Subsample  2b),  all  but  four lower-order dimensions (Callousness, Rejection, Intimacy Problems, and Compulsivity) demonstrated significant  accuracy.  For  the  DAPPBQ-A, non-significant accuracy was only found for Compulsivity. Several dimensions performed particularly well (≥.80); these included higher-order Emotional  Dysregulation  as  well  as  lower-order Anxiety, Social Avoidance, Suspiciousness, SelfHarm,  Restricted  Expression,  and,  again,  Identity Problems  and  Affective  Instability.  Finally,  all  but four lower-order dimensions (Narcissism, Rejection, Intimacy Problems, and Compulsivity) showed significant  accuracy  with  regard  to  distinguishing between referred adolescents without PD (Subsample  2a)  and  referred  adolescents  with  PD (Subsample 2b). Although none of the dimensions had  an  area  under  the  curve  of  greater  than  .80, several dimensions demonstrated fair accuracy (e.g., Emotional Dysregulation, Suspiciousness, SelfHarm, and Conduct Problems).

## Discussion

The  aim  of  the  present  study  was  to  examine  the psychometric qualities of a comprehensive  and concise  instrument-the  DAPP-SF-A-to  assess dimensions of personality pathology in adolescents. The results seem to indicate that the DAPP-SF-A is as  reliable  and  valid  as  its  longer  counterpart,  the DAPP-BQ-A. The results of  the  present  study,  in combination  with  the  advantages  of  the  smaller number of items, are promising with regard to the usefulness  of  the  DAPP-SF-A  in  both  clinical  and research settings.

The  four-factor  solutions  of  the  DAPP-SF-A resemble  previously  reported  factor  structures  of the  full-length  versions,  both  the  adult  DAPP-BQ (13,16,17,19,32,39-41)  and  the  adolescent  DAPPBQ-A (24). Parallel  analysis  demonstrated  that  the eigenvalue of Compulsivity did not exceed the 95th percentile random data eigenvalue. Previous studies suggested  that  Compulsivity  stands  apart  from  the other higher-order dimensions. Individuals with high levels of Compulsivity as assessed with the use of  the  DAPP-BQ-A seem to be less dysfunctional than those with high levels of Emotional Dysregulation, Dissocial Behavior, or Inhibitedness. Compulsivity thus seems to tap into adaptive rather than maladaptive compulsive behaviors (42,43). Although  the  assessment  of  compulsive  behaviors seems necessary for a comprehensive representation of  the  full  array  of  personality  pathology  (4),  the present wording of items that tap into the Compulsivity  factor  in  the  DAPP-SF-A  requires further investigation.

Despite  overall  high  concordance  of  the  factor structure  reported  in  the  present  study  with  those found in previous studies, two findings merit further  attention.  First,  the  pattern  of  loadings  of the DAPP-SF-A seems less diffuse than that of the DAPP-BQ-A. For example, the construct of narcissism  as  measured  by  the  DAPP-SF-A  loads more clearly on one factor (i.e., Dissocial Behavior) than it does as measured by the DAPP-BQ-A. This may contradict a previously expressed concern that the construct is not yet clearly defined in adolescents  (24).  Instead,  the  diffuse  pattern  of loadings  reported  in  the  previous  study  may  have resulted  from  its  conceptualization  in  the  DAPPBQ-A. Several previous studies in adult populations involving  the  use  of  either  the  DAPP-BQ  or  the DAPP-SF  have  reported  high  (or  even  highest) loadings  of  Narcissism  on  Dissocial  Behavior  (1517,30). This may be caused by the genetic factor of grandiosity, which underlies the dimension of Narcissism and  which  loaded  on  the Dissocial Behavior factor (44).

A  second  finding  involving  the  factor  structure that merits attention is that, for the factor Inhibitedness,  a  high  loading  was  found  only  with Intimacy Problems. Previous studies involving both adults  and  adolescents  found  high  loadings  for Restricted  Expression  as  well  (24,30),  which  is  in line  with  expectations  based  on  Livesley's  studies (15,45). In the present study, Restricted Expression loaded most strongly on the Emotion Dysregulation factor.  A  previous  study  of  adolescents  using  the DAPP-BQ-A (24) reported a high cross-loading of Restricted Expression on the Emotion Dysregulation  factor.  Perhaps  in  adolescents  the avoidance  of  expression  of  emotions  and  personal information  is  more  closely  related  to  traits  like suspiciousness, identity problems, and social avoidance.

Several  other  findings  reported  in  the  present study indicate that the psychometric qualities of the full-length  DAPP-BQ-A (24)  can  be  replicated  for the DAPP-SF-A.  Internal  consistency  and  testretest  reliability  coefficients  were  good,  except  for the  test-retest  reliability  of  lower-order  Intimacy Problems.  The  dimensions  of  the  DAPP-SF-A showed  adequate discriminative validity. Several dimensions demonstrated large effects in the distinction  between  samples  defined  by  varying severity of psychopathology. Given the fact that the DAPP-SF-A  includes  only  half of the original number of items in the DAPP-BQ-A, these results are especially promising.

Gender and age effects on personality pathology were  in  line  with  results  reported  for  the  DAPPBQ-A  (24). In general, girls score higher on internalizing  forms  of  personality  pathology  (e.g., dimensions within Emotional Dysregulation), whereas  boys  score  higher  on  externalizing  forms (e.g., dimensions within Dissocial Behavior). Therefore,  gender  effects  must  be  accounted  for when  norms  are  developed  for  the  DAPP-SF-A. Longitudinal  studies  have  shown  that  personality pathology peaks during early adolescence and declines thereafter (46). The age effects found in the present  study  represented  higher  scores  for  older adolescents. However, effects were small in term of Cohen's  criteria. In  addition, the  cross-sectional nature of the present data prevents a reliable comparison being made with previous studies that have reported longitudinal data.

With  regard  to  classification  accuracy,  although the vast majority of DAPP-SF-A dimensions showed  significant  accuracy,  they  showed  good accuracy  (≥.80)  only  for  the  distinction  between non-referred  adolescents  and  referred  adolescents with a PD. However, similar results were found for the full-length DAPP-BQ-A. Therefore, it is unlikely that this should be attributed to the shortening  of  the  questionnaire.  In  addition,  as argued previously elsewhere (24), distinguishing among  subsamples  within  a  referred  sample  (e.g., among referred adolescents with or without PDs) is particularly  difficult  as  a  result  of  the  overlap  in psychopathology. In the present study, many referred adolescents without PDs  demonstrated several  individual  PD  symptoms  without  meeting the  diagnostic  threshold  to  qualify  for  a  full  PD

diagnosis. Alternatively, 100% of referred adolescents  with  PDs  also  qualified  for  Axis  I diagnoses. This constitutes an intrinsically diagnostic  problem  that  is  seemingly  inevitable  in psychopathology research that involves referred samples.

## Clinical Implications

Considering the growing evidence for the existence of personality pathology before the age of 18 years as  well  as  the  introduction  of  a  hybrid  categoricaldimensional perspective on personality pathology in the  DSM-5,  the  DAPP-SF-A  may  prove  to  be  a relevant  instrument  in  clinical  settings.  It  can  be implemented as a standard diagnostic and evaluation tool in youth mental health services. The early  detection  of  possible  personality  pathology followed  by  timely  intervention  may  avert  later dysfunction (21).

## Limitations

The  analyses  reported  in  the  present  study  were partly  conducted  with  the  use  of  the  same  sample that was used to examine the psychometric qualities of  the  DAPP-BQ-A.  The  use  of  the  same  dataset has an advantage in that possible differences in the results  cannot  be  attributed  to  sample  differences. However, it can be argued that the use of the same data set may have led to a spurious overlap between the  factor  structures  of  the  DAPP-BQ-A  and  the DAPP-SF-A.  The  DAPP-SF-A  is  currently  being examined  in  an  independent  sample.  When  this sample reaches an adequate size, the factor structure will be examined, and Tucker coefficients of congruence  will  be  computed  to  investigate  any factor similarities between the original samples and the independent sample.

Apart  from  several  adaptations  to  increase  the age-appropriateness  of  the  items  (24),  the  DAPPSF-A investigated in the present study was comprised of the same items  as the DAPP-SF for adults  (30).  From  a  developmental  perspective,  it may  have  been  appropriate  to  use  a  bottom-up procedure  to  create  a  short  form  specifically  for adolescents  by  applying  a  similar  selection  process for  adolescents  as  was  done  for  adults.  However, longitudinal research into the development of personality  pathology  may  profit  from  the  use  of identical instruments for different age groups. Similarly, if researchers from other countries wish to develop a short form of the DAPP-BQ-A, they may prefer  to  include  the  same  items  as  the  version under  investigation  in  the  present  study.  This  may facilitate the cross-cultural comparison of data regarding personality pathology in adolescents.

## Conclusion

The  current  findings  support  the  reliability  and validity  of  an  abbreviated  instrument-the  DAPPSF-A-to  assess  personality  pathology  dimensions in  adolescents.  This  instrument  allows  for  both comprehensive  and concise assessment, thereby increasing  the  feasibility  of  the  widespread  use  of the DAPP-SF-A  in  both research and clinical settings.

## References

1. Mullins-Sweatt  SN,  Bernstein  DP,  Widiger  TA.  Retention  or deletion  of  personality  disorder  diagnoses  for  DSM-5:  An  expert consensus approach. J Pers Disord 2012;26:689-703.
2. Shedler J,  Beck  A,  Fonagy  P,  Gabbard  GO,  Gunderson  J, Kernberg O, et al. Personality disorders in  DSM-5.  Am  J Psychiatry 2010;167:1026-8.
3. Widiger TA. What would Jerry do? Rejoinder for 'A postmortem and future look at the personality disorders in DSM-5'. Personality Disorders: Theory, Research, and Treatment 2013;4:392.
4. American Psychiatric Association. Diagnostic and statistical manual of mental disorders (5 th  ed). Washington, DC: 2013.
5. Clark  LA.  Assessment  and  diagnosis  of personality disorder: Perennial  issues  and  an  emerging  reconceptualization.  Annu  Rev Psychol 2007;58:227-57.
6. Trull  TJ,  Durrett  CA.  Categorical  and  dimensional  models  of personality disorder. Annu Rev Clin Psychol 2005;1:355-80.
7. Widiger TA, Samuel DB. Diagnostic categories or dimensions? A question  for  the  Diagnostic  and  Statistical  Manual  of  Mental Disorders - Fifth Edition. J Abnorm Psychol 2005;114:494-504.
8. Widiger  TA,  Livesley  WJ,  Clark  LA.  An  integrative  dimensional classification  of  personality disorder. Psychol  Assess  2009;21:24355.
9. Widiger  TA,  Simonsen  E.  Alternative  dimensional  models  of personality  disorders:  Finding  a  common  ground.  J  Pers  Disord 2005;19:110-30.
10. Livesley WJ, Jackson DN. Dimensional Assessment of Personality Pathology  -  Basic  Questionnaire:  Technical  manual.  Port  Huron, MI: Sigma Press; 2009.
11. Krueger  RF,  Derringer  J,  Markon  KE,  Watson  D,  Skodol  AE. Initial  construction  of  a  maladaptive  personality  trait  model  and inventory for DSM-5. Psychol Med 2012;42:1879-90.
12. Van den Broeck J, Bastiaansen L, Rossi G, Dierckx E, De Clercq B,  Hofmans  J.  Hierarchical  structure  of  maladaptive  personality traits  in  older  adults:  Joint  factor  analysis  of  the  PID-5  and  the DAPP-BQ. J Pers Disord 2014;28:198-211.
13. Bagge CL, Trull TJ. DAPP-BQ: Factor structure and relations to personality  disorder  symptoms  in  a  non-clinical  sample.  J  Pers Disord 2003;17:19-32.
14. Brezo  J,  Paris  J,  Tremblay  R,  Vitaro  F,  Turecki  G.  DAPP-BQ: Factor structure in French Canadians. J Pers Disord 2008;22:53845.
15. Livesley WJ, Jang  KL,  Vernon  PA.  Phenotypic  and  genetic structure of traits delineating  personality  disorder.  Arch  Gen Psychiatry 1998;55:941-8.
16. Maruta  T,  Yamate  T,  Iimori  M,  Kato  M,  Livesley  WJ.  Factor structure of the Dimensional Assessment of Personality Pathology-

- Basic  Questionnaire  and  its  relationship  with  the  Revised  NEO Personality  Inventory  in  a  Japanese  sample.  Compr  Psychiatry 2006;47:528-33.
17. Pukrop R, Gentil I, Steinbring I, Steinmeyer E. Factorial structure of the German  version of the Dimensional Assessment of Personality Pathology-Basic Questionnaire in clinical and nonclinical samples. J Pers Disord 2001;15:450-6.
18. Pukrop R, Steinbring I, Gentil I, Schulte C, Larstone R, Livesley WJ. Clinical validity of the 'Dimensional Assessment of Personality  Pathology  (DAPP)'  for  psychiatric  patients  with  and without a personality disorder diagnosis. J Pers Disord 2009;23:572-86.
19. Van  Kampen  D.  The  DAPP-BQ  in  The  Netherlands:  Factor structure and relationship with basic personality dimensions. J Pers Disord 2002;16:235-54.
20. Wang  W,  Du  W,  Wang  Y,  Livesley  WJ,  &  Jang  KL.  The relationship between the Zuckerman-Kuhlman Personality Questionnaire  and  traits  delineating  personality  pathology.  Pers Indiv Differ 2004;36:155-62.
21. Johnson  JG,  Bromley  E,  Bornstein  RF,  Sneed  JR.  Adolescent personality disorders. In: Wolfe DA, Mash EJ, eds, Behavioral and emotional disorders in children and adolescents: nature, assessment, & treatment. New York: Guilford Press; 2006. p. 46384.
22. Mervielde I, De  Clercq B, De  Fruyt F,  Van  Leeuwen  K. Temperament, personality, and developmental psychopathology as childhood  antecedents  of  personality  disorders.  J  Pers  Disord 2005;19:171-201.
23. World Health Organization. International  Statistical  Classification of  Diseases  and  Related  Health  Problems  (10 th   rev).  Geneva: WHO; 2010.
24. Tromp  NB,  Koot  HM.  Dimensions  of  personality  pathology  in adolescents:  Psychometric  properties  of  the  DAPP-BQ-A.  J  Pers Disord 2008;22:623-38.
25. Tromp  NB,  Koot  HM.  Dimensions  of  personality  pathology  in adolescents: Relations to DSM-IV personality disorder symptoms. J Pers Disord 2009;23:514-27.
26. Tromp  NB,  Koot  HM.  Dimensions  of  normal  and  abnormal personality: Elucidating DSM-IV personality disorder symptoms in adolescents. J Pers 2010;78:839-64.
27. De Clercq B, De Fruyt F, De Bolle M, Van Hiel A, Markon KE, Krueger RF. The hierarchical structure and construct validity of the PID-5 trait measure in adolescence. J Pers 2014;82:158-169.
28. De  Beurs  E,  Rinne  Th,  Van  Kampen  D,  Verheul  R,  Andrea  H. Reliability  and  validity  of  the  Dutch  Dimensional  Assessment  of Personality Pathology-Short Form (DAPP-SF), a shortened version of the DAPP-Basic Questionnaire. J Pers Disord 2009;23:308-26.
29. De  Beurs  E,  Rinne  Th,  Van  Kampen  D,  Verheul  R,  Andrea  H. Criterion-related  validity  of  the  DAPP-SF  and  its  utility  as  a screener for personality disorders in outpatient care. Personal Ment Health 2010;4:271-83.
30. Van  Kampen  D,  De  Beurs  E,  Andrea  H.  A  short  form  of  the Dimensional Assessment of Personality Pathology-Basic Questionnaire (DAPP-BQ): The DAPP-SF. Psychiatry Res 2008;160:115-28.
31. Smith GT, McCarthy DM, Anderson, KG. On the sins of shortform development. Psychol Assess 2000;12:102-11.
32. Van  Kampen  D.  The  Dutch  DAPP-BQ:  Improvements,  lowerand  higher-order  dimensions,  and  relationship  with  the  5DPT.  J Pers Disord 2006;20:81-101.
33. Varni  JW,  Seid  M,  Rode  CA.  The  PedsQL:  Measurement  model for the Pediatric Quality of Life Inventory. Med Care 1999;37:12639.
34. Weertman A, Arntz A, Dreessen L, van Velzen C, Vertommen S. Short-interval test-retest  interrater  reliability  of  the  Dutch  version of the Structured  Clinical  Interview  for  DSM-IV  Personality Disorders SCID-II. J Pers Disord 2003;17:562-7.
35. First  MB,  Spitzer  RL,  Gibbon  M,  Williams  JBW.  Structured Clinical  Interview  for  DSM-IV  Personality  Disorders  (SCID-II). Washington, DC: American Psychiatric Press; 1997.
36. Horn JL. A rationale and test for the number of factors in factor analysis. Psychometrika 1965;30:179-85.
37. Stevens  JP.  Applied  multivariate  statistics  for  the  social  sciences (5 th  ed). New York: Routledge; 2009.
38. Cohen J. Statistical power analysis for the behavioral sciences (2 nd ed). Hillsdale, NJ: Erlbaum; 1988.
39. Livesley  WJ,  Jackson  DN,  Schroeder  ML.  Factorial  structure  of traits delineating personality disorders in clinical and general population samples. J Abnorm Psychol 1992;101:432-40.
40. Schroeder  ML,  Wormworth  JA,  Livesley  WJ.  Dimensions  of personality disorder and their relationships to the Big Five dimensions of personality. Psychol Assess 1992;4:47-53.
41. Zheng  W,  Wang  W,  Huang  Z,  Sun  C,  Zhu  J,  Livesley  WJ.  The structure  of  traits  delineating  personality  disorder  in  a  Chinese sample. J Pers Disord 2002;16:477-86.
42. Tromp  NB,  Koot  HM.  Self-  and  parent  report  of  adolescent personality pathology: Informant agreement and relations to dysfunction. J Pers Disord 2010;24:151-70.
43. Tromp NB, Koot HM. Adolescent personality pathology: Associated personal and ecological factors. Manuscript in preparation .
44. Livesley  WJ.  Behavioral  and  molecular  genetic  contributions  to a dimensional  classification  of  personality  disorders.  J  Pers  Disord 2005;19:131-55.
45. Livesley WJ, Jackson DN. Dimensional Assessment of Personality Pathology -  Basic  Questionnaire:  Technical  manual.  Port  Huron, MI: Sigma Press; 2009.
46. Cohen P, Crawford TN, Johnson JG, Kasen S. The children in the community study of development course of personality disorder. J Pers Disord 2005;19:466-86.