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 RESEARCH ARTICLE

Personality disorder in ADHD
Part 1: Assessment of personality disorder in adult ADHD using data from a clinical trial of OROS methylphenidate

Erika D. Williams, MSW

Mood Disorders Clinic, Department of Psychiatry, University of Utah, Salt Lake City, UT, USA

Frederick W. Reimherr, MD

Mood Disorders Clinic, Department of Psychiatry, University of Utah, Salt Lake City, UT, USA

Barrie K. Marchant, MS

Mood Disorders Clinic, Department of Psychiatry, University of Utah, Salt Lake City, UT, USA

Robert E. Strong, DO

Mood Disorders Clinic, Department of Psychiatry, University of Utah, Salt Lake City, UT, USA

Corinne Halls, MS

Mood Disorders Clinic, Department of Psychiatry, University of Utah, Salt Lake City, UT, USA

Poonam Soni, MD

Mood Disorders Clinic, Department of Psychiatry, University of Utah, Salt Lake City, UT, USA

Phillip D. Gale, MD

Mood Disorders Clinic, Department of Psychiatry, University of Utah, Salt Lake City, UT, USA

Reid J. Robison, MD

Mood Disorders Clinic, Department of Psychiatry, University of Utah, Salt Lake City, UT, USA

BACKGROUND: Comorbidity of personality disorder (PD) and attention-deficit/hyperactivity disorder (ADHD) has been suggested in several reports. However, assessment of PD is problematic, and studies have over-relied on baseline evaluations.

METHODS: Forty-seven patients entered a double-blind trial of osmotic release oral system (OROS) methylphenidate (MPH). Patients were assessed at baseline with the Wisconsin Personality Inventory IV (WISPI-IV) and the Structured Clinical Interview for DSM-IV Axis II Personality Disorders (SCID-II). Following the study, all information—including tests, family reports, and extended clinical observations—produced a final PD diagnosis. Three post hoc categories were created: PD-negative (no PD), PD-positive (1 PD), and PD-plus (2 or more PDs).

RESULTS: Twenty-one (45%) patients had a PD on the final assessment vs 62% using SCID-II and 33% using WISPI-IV; final PD diagnosis revealed 9% cluster A, 17% cluster B, and 28% cluster C. Twenty-one percent of patients experienced multiple disorders. Using a weighted kappa, the number of PDs on the final assessment correlated with the WISPI-IV (κ =.53; P > .001) and the SCID-II (κ =.70; P < .001). However the SCID-II overidentified and the WISPI-IV underidentified PD.

CONCLUSION: Almost all PDs were represented in this sample, and past emphasis on cluster B appears unwarranted. Although the SCID-II and WISPI-IV had limited success in identifying specific PDs, they were more successful in identifying the number of PDs present in each patient. The small sample makes these findings preliminary.

KEYWORDS: ADHD, adult, personality disorder, Wisconsin Personality Inventory-IV (WISPI-IV), SCID-II

ANNALS OF CLINICAL PSYCHIATRY 2010;22(2):84-93

  INTRODUCTION

Attention-deficit/hyperactivity disorder (ADHD) is a common childhood illness that continues into adulthood for many patients. Studies have reported that ADHD is associated with a confusingly wide array of other disorders, including oppositional defiant disorder (ODD), conduct disorder (CD), specific learning disabilities (eg, dyslexia), substance abuse,1 various anxiety disorders including obsessive-compulsive disorder (OCD), major depression, dysthymia, bipolar disorder,2,3 and personality disorder (PD).

The PD spectrum most closely associated with ADHD is CD in adolescence and antisocial disorder in adults.4-9 Beyond that, there is a gradually expanding literature connecting ADHD to other PDs within cluster B.10-13 The relationship between cluster C diagnoses and ADHD has been less explored, but several studies have reported a positive relationship. May and Bos14 identified 4 subgroups of ADHD adults, one of which was more often avoidant and dependent in personality style. Burket et al,15 in an assessment of girls with ADHD, found that dependent PDs were significantly more frequent in an ADHD group than a non-ADHD clinical sample. Modestin et al,16 in a study of opioid dependence, found that a history of ADHD was associated with OCD. Güçlü and Erkiran17 also found high levels of OCD in an ADHD sample. Finally, Miller et al18 found that patients with ADHD-combined type met DSM-IV criteria for similar levels of cluster B (21.9%) and cluster C (23.4%) diagnoses. Patients with ADHD-inattentive type also had comparable levels of cluster B (20.3%) and cluster C (20.3%) diagnoses. In contrast, they found that adult patients with ADHD-hyperactive type had higher levels of cluster B (47.4%) than cluster C (15.8%) diagnoses.

Unfortunately, the assessment of PD is fraught with uncertainty. Although informative, none of these reports of PD in adults with ADHD have included a second measure to assess concurrent validity. In PD, the agreement or concurrent validity between alternative measures is often poor. There are reports of poor agreement between physician and research interviewer19; self-report techniques and expert consensus20; physician assessment and a self-report scale21; and self-report techniques and interview approaches.21-24

Currently, the systems for detection of PD considered most accurate use either an extended clinician-administered structured interview or a 2-stage system using a screening questionnaire followed by a clinician interview,25 both of which are time consuming. Unfortunately, even extensive interviews often result in significant disagreement, as demonstrated in several studies comparing interviews of patients and family informants.26-28 Family informants often reveal the presence of a PD in patients not previously identified using other methods. In a review, Perry29 concluded that although various personality assessment methods are reliable, they provide limited cross-method diagnostic validity. It is doubtful that the methodology has improved in the intervening years.

The difficulties in assessing PD may be exacerbated in patients with ADHD, who have poor memory, are easily distracted, and resist extended questioning. When questioned, they may become impatient, defensive, and angry. Often when an adult with ADHD presents for treatment, it is because the symptoms of ADHD have created a “crisis.” The high emotions accompanying the crisis often blur our understanding of how the patient normally interacts with others.30 Additional difficulties are caused by the symptom overlap between ADHD and several PDs. For example, borderline PD and ADHD share the symptoms of temper, impulsivity, affective instability, and boredom. Although the symptoms differ both in intensity and qualitatively between the 2 conditions, these differences may not be addressed by a particular evaluation instrument.

This study used a clinical sample from an osmotic release oral system (OROS) methylphenidate (MPH) clinical trial to compare the results of 2 different baseline assessments of PD with a final consensus assessment that used all available information from the patient’s research experience. These assessments were used to identify the presence or extent of PD as well as to identify specific disorders. The Structured Clinical Interview for DSM-IV Axis II Personality Disorders (SCID-II) was selected because it is the most commonly accepted method of ascertaining PD. The Wisconsin Personality Disorders Inventory IV (WISPI-IV) was selected because it is based on an interpersonal perspective, with questions placed in a social context. The design of this study allowed extended contact with each patient as well as their significant other, resulting in a more clinically informed Axis II diagnosis than is commonly reported in the ADHD literature.

An alternative use for personality assessments would be as a screening device to indicate the presence or extent of disorder rather than providing a specific diagnosis.31 Several studies have found good agreement between interview techniques and self-report scales regarding the presence or absence of PD23,32 or dimensions of personality.33 Used in this manner, a self-report screening system might be worthwhile.31

The questions addressed by this study were:

  1. To what extent were specific PDs and the 3 DSM-IV PD clusters present in this adult ADHD clinical sample?

  2. To what degree did the SCID-II and WISPI-IV agree with the final personality assessment regarding the presence of each specific PD and Axis II cluster?

  3. To what degree did the SCID-II and WISPI-IV agree with the final personality assessment regarding the number of PDs present in each patient?

  METHODS

The University of Utah Institutional Review Board reviewed and approved the study. The study was conducted in accordance with the 1975 Declaration of Helsinki. This was a placebo-controlled trial of OROS MPH containing a screening/baseline phase followed by a double-blind crossover phase with two 4-week arms. Patients completing the crossover phase entered a 6-month open-label treatment phase.

Following an initial screening interview, informed consent was obtained. Evaluation of PDs was conducted as follows. Patients completed the SCID-II screening questionnaire and SCID-II interviews, which were performed by the same clinician (E.D.W.), who is experienced in both initial evaluations and use of programmed interviews. Patients next completed the self-report WISPI-IV. Last, patients were assessed using the Iowa Personality Disorder Screen (IPDS) by one of the study psychiatrists. Assessment using the IPDS was repeated at the end of each double-blind arm plus the open-label period, with the intent of maintaining awareness of the patient’s personality characteristics during the course of the study. Following the conclusion of the patient’s participation in the study, all available information (including the aforementioned tests, family report, reports from other staff, DSM-IV criteria, and clinical observations) was reviewed by the 3 treating psychiatrists (F.W.R., P.S., and R.E.S.) and a consensus decision regarding the patient’s PD was made. The decision to use 3 groups assessing the amount of PD was made in response to the previously identified studies suggesting that PD assessment measures might demonstrate more agreement when used in that manner. The idea of separating PD patients based on the extensiveness of PD symptomatology has been successfully used in other research settings. For example Black et al34 found it efficacious to separate patients into 4 groups based on the number of borderline symptoms. However, cutpoints for the 3 post hoc groups were based on the pragmatic fact that separating patients with 1 vs 2 or more PDs resulted in similar numbers of patients in the 2 groups rather than prior statistical analysis or research.

Study population

Patients were required to meet DSM-IV-TR criteria for current ADHD based on the Conners’ Adult ADHD Diagnostic Interview for DSM-IV with at least moderate ADHD symptoms and the Utah Criteria for ADHD in adults. Patients were between age 18 and 65. The following DSM-IV Axis I diagnoses were exclusionary: current diagnosis of major depressive disorder, panic disorder, current or lifetime bipolar disorder, schizophrenia, and other psychotic disorder. Current substance abuse disorders were also exclusionary. Recruitment occurred through advertising and referrals to our clinic. Several patients were also recruited from our clinic population. A more complete description of the selection process has been previously reported.35

Measures

The IPDS36 is a structured interview that can be completed in less than 5 minutes. It contains questions regarding 11 symptom dimensions. Despite its short length, its sensitivity in detecting the presence of PD was 79% in a group of nonpsychotic patients.

The SCID-II is an interview-based assessment system for PD using a 2-step system. The patient completes a screening questionnaire and then a follow-up interview is conducted checking on areas that the patient has rated over a threshold level based on the number of items endorsed. The SCID Screen questionnaire has been evaluated as an independent measure of PD and, in comparison to the full SCID-II, produced no false negatives but a number of false positives.37 In a comparison to the more time-intensive International Personality Disorder Examination, the SCID-II has shown a similar rate of false negatives.38 Patients were separated into 3 categories: PD-negative (patients not meeting criteria for any PD), PD-positive (patients meeting criteria for no more than 1 PD), and PD-plus (patients meeting criteria for at least 2 PDs).

The WISPI-IV39 is a self-administered scale consisting of 214 items that presents DSM-IV criteria from an interpersonal perspective40 with demonstrated validity.41 Although the WISPI-IV and SCID-II have shown low levels of agreement regarding specific personality diagnosis, they have shown good levels of agreement regarding presence or absence of PD. Patients were categorized as meeting full criteria for a PD if they met the test developer’s criteria for a diagnosis, consisting of: (a) meeting 100% of DSM “necessary items;” and (b) the percentage of “necessary items” exceeded the percentage of “exclusionary items” by at least 50%. As with the SCID-II, patients were segregated into 3 categories: PD-negative (patients not meeting criteria for any PD), PD-positive (patients meeting criteria for only 1 PD), and PD-plus (patients meeting diagnostic criteria for at least 2 PDs). In addition to reporting on necessary and exclusionary items, the WISPI-IV generates z scores based on a comparison of the patient’s responses to a normative sample. Although z scores are not used in the diagnosis of PD, they effectively portray the extensiveness of each disorder.

A final diagnostic consensus PD assessment was completed for each patient at the end of his or her participation. This was done by the treating psychiatrists (P.S., F.W.R., and/or R.E.S.). Each case was reviewed by 2 of the psychiatrists, the treating psychiatrist and one of the 2 other psychiatrists. All information was considered, including IPDS, SCID-II, and WISPI-IV, in reaching a final decision. The final psychiatric assessment was used as our “gold standard” of the patient’s personality status. Using it, patients were separated into 3 post hoc categories: PD-negative (patients without a PD), PD-positive (patients meeting diagnostic criteria for only 1 PD), and PD-plus (patients meeting diagnostic criteria for 2 or more PDs).

Data analysis and statistical procedures

To assess the diagnostic accuracy of the WISPI-IV and the SCID-II, the sensitivity, specificity, positive predictive power, and negative predictive power were calculated. Agreement regarding the more general categories of PD-negative, PD-positive, and PD-plus was further assessed using Wilcoxon signed rank test comparing the SCID-II and WISPI-IV to the psychiatrist’s final assessment. Diagnostic agreement of the WISPI-IV and SCID-II with the final psychiatric assessment regarding the presence of any PD within a cluster was assessed with the McNemar test, using the 2-sided exact binomial test.

A weighted kappa was used to compute agreement between the number of PDs identified by the final assessment with the number identified by both the SCID-II and WISPI-IV.

All analyses were done using the SPSS 13.0 statistical package. All statistics were 2-tailed, with P < .05. Given the exploratory nature of the study, Bonferroni corrections were not applied.

  RESULTS

Forty-seven patients entered the study and were assessed for presence of PD. As seen in TABLE 1, 45% of patients had at least 1 PD. The percentage of patients experiencing a disorder in cluster A was lower (9%) than in cluster B (17%). Both clusters A and B were lower in frequency than C (28%). All 3 methods showed this same relative order of frequency. Twenty-one percent of patients met criteria for 2 or more diagnoses in our final assessment. Due to the small numbers involved, there was not statistical agreement regarding specific clusters as assessed with McNemar test, using the 2-sided exact binomial test (except for the agreement between the final assessment and cluster B on the SCID-II [McNemar exact test, P=.031]). A complete description of the patient population has been previously reported,35 and information regarding the demographic and psychosocial characteristics of our 3 PD groups is presented in the last 2 articles in this series: Personality disorders in ADHD Part 2: The effect of symptoms of personality disorder on response to treatment with OROS methylphenidate in adults with ADHD and Personality disorder in ADHD Part 3: Personality disorder, social adjustment, and their relation to dimensions of adult ADHD.

There was limited agreement between the SCID-II and the final assessment regarding the presence of specific PDs. As seen in TABLE 2, this agreement improved somewhat at the cluster level. Using the final assessment as the standard, the SCID-II overestimated the presence of PDs in the PD-positive and PD-plus groups. This was reflected in the sensitivity and specificity calculations for PD-negative and PD-plus displayed in TABLE 2. The SCID-II identified PD-negative patients with sensitivity=.65 and specificity=.90, and PD-plus patients with sensitivity=.90 and specificity=.84. Sensitivity and negative predictive power were generally higher than specificity or positive predictive power.

As seen in TABLE 3, agreement between the WISPI-IV and the final assessment regarding the presence of specific PDs was also limited. Using the final assessment as the standard, the WISPI-IV underestimated the presence of PD. The WISPI-IV identified PD-negative patients with sensitivity=.92 and specificity=.67, and PD-plus patients with sensitivity=.40 and specificity=1.00. Its scoring procedure resulted in only 15 patients receiving a PD diagnosis. This affected the statistics displayed in TABLE 3 in the opposite direction of the SCID-II such that sensitivity and negative predictive power were generally lower than specificity or positive predictive power.

In contrast to specific PDs, there was substantial agreement regarding PD status (PD-negative, PD-positive, and PD-plus). On the Wilcoxon matched-pairs signed rank test, the SCID-II agreed with the final diagnostic assessment regarding PD group at a significant level (z=2.4; P=.02). A similar relationship was found for the WISPI-IV (z=2.5; P=.01).

As shown in TABLE 4, there was substantial agreement between the 2 baseline assessments and the final assessment regarding the number of Axis II diagnoses in each patient. Agreement between the number of diagnoses identified by the SCID-II and the final PD assessment was significant as assessed using a weighted kappa (κ =.70; P < .001), and Spearman’s rho found significant consistency (r =.74; P < .001) between the 2. Agreement between the WISPI-IV and the final PD assessment was also significant as assessed using a weighted kappa (κ =.53; P < .001), and Spearman’s rho found significant consistency (r =.65; P > .001) between the 2. The average number of SCID-II items endorsed by each patient increased from 34.0±14.9 for PD-negative patients, to 70.9±11.2 for the PD-plus patients. Similarly, the average z score on the WISPI-IV increased from –0.1±0.6 for PD-negative patients to 1.7±1.2 for the PD-plus patients. There was a significant correlation between the number of SCID-II items endorsed by each patient and their WISPI-IV average z score (r=.78; P < .001).

The FIGURE presents a scatter plot of the individual WISPI-IV z scores plotted against the number of SCID-II items endorsed. As noted above, there is a clear correlation between these 2 measures. The 3 PD groups are noted with different symbols. Although the means noted in TABLE 4 are different, there is overlap.


TABLE 1

Specific personality disorders: Number and percentage of patients meeting criteria using the SCID-II and WISPI-IV, and the final personality diagnosis (N = 47)

  Final personality diagnosis SCID-II WISPI-IV
  n % n % n %
CLUSTER A
Paranoid 4 9% 5 11% 3 6%
Schizoid 0 0% 0 0% 0 0%
Schizotypal 0 0% 0 0% 0 0%
Any cluster A diagnosis 4 9% 5 11% 3 6%
CLUSTER B
Antisocial 4 9% 7 15% 0 0%
Borderline 7 15% 11 23% 1 2%
Histrionic 1 2% 1 2% 3 6%
Narcissistic 1 2% 1 2% 3 6%
Any cluster B diagnosis 8 17% 13 28% 5 11%
CLUSTER C
Avoidant 9 19% 12 26% 8 17%
Dependent 3 6% 2 4% 1 2%
Obsessive-compulsive 4 9% 9 19% 4 9%
Any cluster C diagnosis 13 28% 17 36% 11 23%
Passive-aggressive 4 9% 4 9% 3 6%
Depressive 5 11% 10 21% na na
NOS 3 6% na na na na
ANY DIAGNOSIS 21 45% 29 62% 15 33%
PD-negativea 26 55% 19 40% 32 68%
PD-positiveb 11 23% 14 30% 11 23%
PD-plusc 10 21% 15 32% 4 9%
na: not applicable; NOS: Not otherwise specified; PD: personality disorder; SCID-II: Structured Clinical Interview for DSM-IV Axis II Personality Disorders; WISPI-IV: Wisconsin Personality Disorders Inventory IV.
aPD-negative: Patients did not meet criteria for a PD.
bPD-positive: Patients met criteria for 1 PD.
cPD-plus: Patients met criteria for ≥2 PDs.

TABLE 2

The ability of the SCID-II to correctly identify the final personality diagnosis (N = 47)

  Final personality diagnosis SCID-II
  n % n % Sensitivity Specificity Positive predictive power Negative predictive power
CLUSTER A
Paranoid 4 9% 5 11% .80 (28 to 99) .98 (87 to 99) .80 (28 to 99) .98 (87 to 99)
Schizoid 0 0% 0 0% na na na na
Schizotypal 0 0% 0 0% na na na na
Any cluster A diagnosis 4 9% 5 11% .80 (28 to 99) .98 (87 to 99) .80 (28 to 99) .98 (87 to 99)
CLUSTER B
Antisocial 4 9% 7 15% 1.00 (29 to 100) .91 (78 to 97) .43 (9 to 81) 1.00 (91 to 100)
Borderline 7 15% 11 23% 1.00 (59 to 100) .90 (76 to 97) .63 (30 to 89) 1.00 (90 to 100)
Histrionic 1 2% 1 2% na na na na
Narcissistic 1 2% 1 2% na na na na
Any cluster B diagnosis 8 17% 13 28% 1.00 (63 to 100) .85 (69 to 94) .57 (28 to 82) 1.00 (89 to 100)
CLUSTER C
Avoidant 9 19% 12 26% 1.00 (66 to 100) .92 (78 to 98) .75 (42 to 94) 1.00 (90 to 100)
Dependent 3 6% 2 4% .50 (6 to 97) 1.00 (91 to 100) 1.00 (15 to 100) .96 (84 to 99)
Obsessive-compulsive 4 9% 9 19% 1.00 (47 to 100) .90 (77 to 97) .56 (21 to 86) 1.00 (90 to 100)
Any cluster C diagnosis 13 28% 17 36% .93 (66 to 99) .82 (64 to 93) .68 (43 to 87) .96 (81 to 99)
Passive-aggressive 4 9% 4 9% .60 (14 to 94) .98 (87 to 99) .75 (19 to 99) .95 (84 to 99)
Depressive 5 11% 10 21% 1.00 (47 to 100) .88 (74 to 96) .50 (18 to 81) 1.00 (90 to 100)
NOS 3 6% na na na na na na
ANY DIAGNOSIS 21 45% 29 62% .91 (69 to 98) .65 (44 to 82) .68 (47 to 84) .89 (66 to 98)
PD-negativea 26 55% 19 40% .65 (44 to 82) .90 (69 to 98) .89 (66 to 98) .68 (47 to 84)
PD-positiveb 11 23% 14 30% na na na na
PD-plusc 10 21% 15 32% .90 (55 to 99) .84 (67 to 93) .60 (32 to 83) .97 (83 to 99)
na: not applicable; NOS: not otherwise specified; PD: personality disorder; SCID-II: Structured Clinical Interview for DSM-IV Axis II Personality Disorders.
aPD-negative: Patients did not meet criteria for a PD.
bPD-positive: Patients met criteria for 1 PD.
cPD-plus: Patients met criteria for ≥2 PDs.

TABLE 3

The ability of the WISPI-IV to correctly identify the final personality diagnosis

  Final personality diagnosis WISPI-IV
  n % n % Sensitivity Specificity Positive predictive power Negative predictive power
CLUSTER A
Paranoid 4 9% 3 6% .40 (5 to 85) .98 (87 to 99) .67 (9 to 99) .93 (81 to 98)
Schizoid 0 0% 0 0% na na na na
Schizotypal 0 0% 0 0% na na na na
Any cluster A diagnosis 4 9% 3 6% .40 (5 to 85) .98 (87 to 99) .67 (9 to 99) .93 (81 to 98)
CLUSTER B
Antisocial 4 9% 0 0% .00 (0 to 70) 1.00 (91 to 100) na .94 (82 to 98)
Borderline 7 15% 1 2% .14 (0 to 57) 1.00 (91 to 100) 1.00 (2 to 100) .87 (73 to 95)
Histrionic 1 2% 3 6% na na na na
Narcissistic 1 2% 3 6% na na na na
Any cluster B diagnosis 8 17% 5 11% .63 (4 to 91) 1.00 (90 to 100) 1.00 (47 to 100) .93 (80 to 98)
CLUSTER C
Avoidant 9 19% 8 17% .56 (21 to 86) .90 (75 to 97) .56 (21 to 86) .90 (75 to 97)
Dependent 3 6% 1 2% .00 (0 to 60) .98 (87 to 99) .00 (0 to 97) .91 (79 to 97)
Obsessive-compulsive 4 9% 4 9% .60 (14 to 94) .98 (87 to 99) .75 (19 to 99) .95 (84 to 99)
Any cluster C diagnosis 13 28% 11 23% .50 (23 to 76) .85 (68 to 94) .58 (27 to 84) .80 (63 to 91)
Passive-aggressive 4 9% 3 6% .40 (5 to 85) .98 (87 to 99) .67 (9 to 99) .93 (81 to 98)
Depressive 5 11% na na na na na na
NOS 3 6% na na na na na na
ANY DIAGNOSIS 21 45% 15 33% .62 (38 to 81) .92 (74 to 99) .87 (59 to 98) .75 (56 to 88)
PD-negativea 26 55% 32 68% .92 (74 to 99) .67 (36 to 80) .75 (56 to 88) .86 (57 to 98)
PD-positiveb 11 23% 11 23% na na na na
PD-plusc 10 21% 4 9% .40 (12 to 73) 1.00 (90 to 100) 1.00 (39 to 100) .86 (72 to 94)
na: not applicable; NOS: not otherwise specified; PD: personality disorder; WISPI-IV: Wisconsin Personality Disorders Inventory IV.
aPD-negative: Patients did not meet criteria for a PD.
bPD-positive: Patients met criteria for 1 PD.
cPD-plus: Patients met criteria for ≥2 PDs.

TABLE 4

Relationships between the SCID-II, WISPI-IV, and the 3 PD categories

  PD-negativea (n=26) PD-positiveb (n=11) PD-plusc (n=10)
SCID-II
No. of diagnoses met by patients (mean ± SD) 0.4 ± 0.6 1.6 ± 1.0 3.4 ± 1.8
No. of endorsed items (mean ± SD)d 34.0 ± 14.9 48.0 ± 11.7 70.9 ± 11.2
WISPI-IV
No. of diagnoses met by patients (mean ± SD) 0.1 ± 0.3 0.5 ± 0.5 2.0 ± 1.9
Average z scores (mean ± SD) –0.1 ± 0.6 0.5 ± 0.8 1.7 ± 1.2
PD: personality disorder; SCID-II: Structured Clinical Interview for DSM-IV Axis II Personality Disorders; WISPI-IV: Wisconsin Personality Disorders Inventory IV.
aPD-negative: Patients did not meet criteria for a PD.
bPD-positive: Patients met criteria for 1 PD.
cPD-plus: Patients met criteria for ≥2 PDs.
dThe total number of items identified as a problem by the patient on the SCID-II.

FIGURE WISPI-IV z-scores plotted against the number of SCID-II items endorsed in the 3 PD categories*

PD: personality disorder; SCID-II: Structured Clinical Interview for DSM-IV Axis II Personality Disorders; WISPI-IV: Wisconsin Personality Disorders Inventory IV.

*PD-negative: patients did not meet criteria for a PD; PD-positive: patients met criteria for 1 PD; PD-plus: patients met criteria for ≥2 PDs

  DISCUSSION

At baseline, both measures—the SCID-II and the WISPI-IV—indicated that a large percentage of ADHD patients in this study had a PD. This was confirmed by our final diagnostic assessment of these patients, in which 11 (23%) were considered to have 1 PD and another 10 (21%) had 2 or more PDs. These data provide powerful support for prior publications that noted an association between adult ADHD and PD. We differ from those findings by our emphasis on the presence of numerous ADHD patients, each of whom meet the criteria for several PDs. Although reports in ADHD have not addressed the presence of patients with several PDs, reports on PD in other populations have noted their presence. For instance, in the normative study done with the WISPI, the patient population averaged 2.19 diagnoses per patient on the SCID.

The 3 measures of PD demonstrated limited agreement for specific Axis II diagnoses. However, all 3 assessment procedures concluded that a large percentage of patients have a broad range of PDs, with cluster C being the most common. This contrasts with the fact that much research has focused on the PDs in cluster B in adults with ADHD. Although many authors focus on the overlap between ADHD and cluster B (inability to control or regulate behavior, affect, and cognition), the high levels of cluster C diagnoses in both this study and that of Miller et al18 indicated a need for a broader research focus. The most frequent diagnoses were avoidant (19%), borderline (15%), and depressive (11%) disorders; however, these patients met criteria for many different PDs, with only 2 Axis II disorders unrepresented in this sample—schizoid and schizotypal.

The SCID-II led to the largest number of diagnoses, and although it successfully identified almost all patients who were subsequently given a PD, it miscategorized a number of PD-negative patients (high sensitivity for PD). In contrast, use of the WISPI-IV led to fewer diagnoses, but all those meeting WISPI-IV criteria for PD-plus remained in that category at the final assessment (high specificity for PD). It is possible that the lower diagnostic rate of the WISPI-IV is due to its theoretical foundation. The questions on the WISPI-IV are constructed to reflect not just the symptoms, but also the patient’s view of each symptom within a social framework. The high rate of diagnosis by the SCID-II and the low rate by the WISPI-IV contrasts with other studies. For example, Guthrie and Mobley30 found that the Millon Clinical Multiaxial Inventory–II, the Minnesota Multiphasic Personality Inventory scales, and the Personality Diagnostic Questionnaire–Revised all had higher diagnostic rates than the SCID-II. Also, Smith et al41 did not report this lower diagnostic rate, although their study used the SCID-II to validate the WISPI-IV.

There was better agreement regarding the extent of PD. This agreement was evidenced in several ways. The 3 assessment measures were significantly correlated regarding the number of diagnoses each patient was given. There was significant agreement regarding the PD categories. Finally, 2 underlying measures of PD—WISPI-IV z scores and the number of SCID-II items endorsed—were significantly correlated. These findings are similar to previous reports,23,32 which also found good interassessment agreement regarding the presence of PD.

The fact that there were diagnostic disagreements is not surprising. As noted in the introduction, Perry29 concluded that although various personality assessment methods are reliable, they provide limited cross-method validity of the diagnosis. This research setting included the additional limitation of an ADHD diagnosis, complicating the Axis II diagnosis. However, both baseline assessments successfully identified the extent of PD. In a different analysis of these data,42 the PD-plus group proved unresponsive to treatment. If that observation is replicated, the ability to identify the extent of PD may prove more useful than the identification of a specific Axis II diagnosis.

Finally, are there ways to improve the accuracy of these instruments in an ADHD population? In the past, in ADHD studies we have attempted to include a significant other in all clinic visits. In our later evaluations, we reviewed each patient’s complete history. In many cases, we found that patients had overemphasized their symptoms, and we rejected the initial SCID-II diagnoses. Consequently, for best accuracy, the SCID-II should be supplemented with additional information and/or observations in adults with ADHD. For critical evaluations, such as genetic studies, this would be important. In contrast, we feel that the system proposed by the developers of the WISPI-IV might be too strict. A number of patients ultimately given a PD diagnosis, who did not meet the WISPI-IV diagnostic criteria, had high relative z scores. Using the z scores as measure of global or dimensional personality maladjustment might be more useful. The WISPI-IV mean z score and the number of items endorsed on the SCID-II are highly correlated, and either can provide a dimensional measure of PD severity.

Limitations

This study was designed as a trial of OROS-MPH in adult ADHD with an exploratory assessment of PD planned with multiple measures to assess concurrent validity. Funding limited the number of patients to levels appropriate for the primary clinical trial. The low cell numbers made our calculations of sensitivity, specificity, positive predictive power, and negative predictive power tentative, especially for the specific PDs. The exclusion of most Axis I diagnoses make this sample unrepresentative of the general ADHD population. Most patients in this study were Caucasian and, given the exploratory nature of the study, we did not control for multiple comparisons. As noted in this article, assessment of PD in ADHD is problematic at best. Finally, a control sample matched for similar levels of emotional distress would be particularly helpful in attempting to understand these results.

  CONCLUSION

Numerous patients (45%) in this clinical sample were found to have 1 or more PDs. Almost all PDs and clusters were represented in this adult ADHD sample, suggesting that past emphasis on cluster B is unwarranted. Although the 3 personality assessments had limited agreement on specific diagnoses, there was substantial agreement on the presence and extent of PD. This higher degree of agreement suggests that baseline assessments are better used for identifying the presence of PD than giving a specific diagnosis. However, the SCID-II overdiagnosed and the WISPI-IV underdiagnosed PD in this sample. Both the WISPI-IV mean z score and items endorsed on the SCID-II can provide a dimensional measure of PD severity, and their usefulness should be explored in future studies of ADHD and PD. Because it is self-administered, the WISPI-IV may be more practical in assessing the presence and extent of PD than the SCID-II. In this clinical trial, the WISPI-IV demonstrated very high specificity for patients with 2 or more PDs. Given the small sample, these findings should be considered preliminary.

ACKNOWLEDGEMENTS: The authors would like to acknowledge Donald W. Black, MD, Professor of Psychiatry, Department of Psychiatry, University of Iowa, for his careful review of an earlier version of this article.

DISCLOSURES: Mr. Marchant receives grant/research support from Ortho-McNeil Pharmaceuticals. Ms. Williams, Drs. Reimherr, Strong, Soni, Gale, and Robison, and Ms. Halls report no financial relationship with any company whose products are mentioned in this article, or with manufacturers of competing products

    REFERENCES

  1. Milberger S, Biederman J, Faraone SV, et al. Associations between ADHD and psychoactive substance use disorders: Findings from a longitudinal study of high-risk siblings of ADHD children. Am J Addict. 1997;6:318–329.
  2. Biederman J, Mick E, Faraone SV, et al. Influence of gender on attention deficit hyperactivity disorder in children referred to a psychiatric clinic. Am J Psychiatry. 2002;159:36–42.
  3. Biederman J, Faraone SV, Monuteaux MC, et al. Gender effects on attention-deficit/hyperactivity disorder in adults, revisited. Biol Psychiatry. 2004;55:692–700.
  4. Myers WC, Burket RC, Otto TA. Conduct disorder and personality disorders in hospitalized adolescents. J Clin Psychiatry. 1993;54:21–26.
  5. Burket RC, Myers WC. Axis I and personality comorbidity in adolescents with conduct disorder. Bull Am Acad Psychiatry Law. 1995;23:73–82.
  6. Johansson P, Kerr M, Andershed H. Linking adult psychopathy with childhood hyperactivity-impulsivity-attention problems and conduct problems through retrospective self-reports. J Pers Disord. 2005;19:94–101.
  7. Secnik K, Swensen A, Lage MJ. Comorbidities and costs of adult patients diagnosed with attention-deficit hyperactivity disorder. Pharmacoeconomics. 2005;23:93–102.
  8. Wilens TE, Kwon A, Tanguay S, et al. Characteristics of adults with attention deficit hyperactivity disorder plus substance use disorder: the role of psychiatric comorbidity. Am J Addict. 2005;14:319–327.
  9. Cukrowicz KC, Taylor J, Schatschneider C, et al. Personality differences in children and adolescents with attention-deficit/hyperactivity disorder, conduct disorder, and controls. J Child Psychol Psychiatry. 2006;47:151–159.
  10. Anckarsäter H, Stahlberg O, Larson T, et al. The impact of ADHD and autism spectrum disorders on temperament, character, and personality development. Am J Psychiatry. 2006;163:1239–1244.
  11. Fossati A, Novella L, Donati D, et al. History of childhood attention deficit/hyperactivity disorder symptoms and borderline personality disorder: a controlled study. Compr Psychiatry. 2002;43:369–377.
  12. Helgeland MI, Kjelsberg E, Torgersen S. Continuities between emotional and disruptive behavior disorders in adolescence and personality disorders in adulthood. Am J Psychiatry. 2005;162:1941–1947.
  13. Miller CJ, Miller SR, Newcom JH, et al. Personality characteristics associated with persistent ADHD in late adolescence. J Abnorm Child Psychol. 2008;36:165–173.
  14. May B, Bos J. Personality characteristics of ADHD adults assessed with the Millon Clinical Multiaxial Inventory-II: evidence of four distinct subtypes. J Pers Assess. 2000;75:237–248.
  15. Burket RC, Sajid MW, Wasiak M, et al. Personality comorbidity in adolescent females with ADHD. J Psychiatr Pract. 2005;11:131–136.
  16. Modestin J, Matutat B, Würmle O. Antecedents of opioid dependence and personality disorder: attention-deficit/hyperactivity disorder and conduct disorder. Eur Arch Psychiatry Clin Neurosci. 2001;251:42–47.
  17. Güçlü O, Erkiran M. Personality disorders in parents of children with attention deficit hyperactivity disorder. Klinik Psikiyatri Dergisi. 2005;8:18–23.
  18. Miller TW, Nigg JT, Faraone SV. Axis I and II comorbidity in adults with ADHD. J Abnorm Psychol. 2007;116:519–528.
  19. Moran P, Rendu A, Jenkins R, et al. The impact of personality disorder in UK primary care: a 1-year follow-up of attenders. Psychol Med. 2001;31:1447–1454.
  20. Wilberg T, Dammen T, Friis S. Comparing Personality Diagnostic questionnaire-4+ with Longitudinal, Expert, All Data (LEAD) standard diagnoses in a sample with a high prevalence of axis I and axis II disorders. Compr Psychiatry. 2000;41:295–302.
  21. Hyler SE, Rieder RO, Williams JB, et al. A comparison of clinical and self-report diagnoses of DSM-III personality disorders in 552 patients. Compr Psychiatry. 1989;30:170–178.
  22. Bronisch T, Mombour W. Comparison of a diagnostic checklist with a structured interview for the assessment of DSM-III-R and ICD-10 personality disorders. Psychopathology. 1994;27:312–320.
  23. Marlowe DB, Husband SD, Bonieskie LM, et al. Structured interview versus self-report test vantages for the assessment of personality pathology in cocaine dependence. J Pers Disord. 1997;11:177–190.
  24. Tenney NH, Schotte CK, Denys DA, et al. Assessment of DSM-IV personality disorders in obsessive-compulsive disorder: comparison of clinical diagnosis, self-report questionnaire, and semi-structured interview. J Pers Disord. 2003;17:550–561.
  25. Lenzenweger MF, Loranger AW, Korfine L, et al. Detecting personality disorders in a nonclinical population. Application of a 2-stage procedure for case identification. Arch Gen Psychiatry. 1997;54:345–351.
  26. Zimmerman M, Pfohl B, Stangl D, et al. Assessment of DSM-III personality disorders: the importance of interviewing an informant. J Clin Psychiatry. 1986;47:261–263.
  27. Zimmerman M, Pfohl B, Coryell W, et al. Diagnosing personality disorder in depressed patients. A comparison of patient and informant interviews. Arch Gen Psychiatry. 1988;45:733–737.
  28. Bernstein DP, Kasapis C, Bergman A, et al. Assessing axis II disorders by informant interview. J Pers Disord. 1997;11:158–167.
  29. Perry JC. Problems and considerations in the valid assessment of personality disorders. Am J Psychiatry. 1992;149:1645–1653.
  30. Williams E, Marchant BK, Reimherr FW. The challenges in diagnosing ADHD in adults. CME LLC/Psychiatric Times; 2007:(suppl 3);15-18.
  31. Davison S, Leese M, Taylor PJ. Examination of the screening properties of the personality diagnostic questionnaire 4+ (PDQ-4+) in a prison population. J Pers Disord. 2001;15:180–194.
  32. Guthrie PC, Mobley BD. A comparison of the differential diagnostic efficiency of three personality disorder inventories. J Clin Psychol. 1994;50:656–665.
  33. Huprich SK. Evaluating NEO Personality Inventory-Revised profiles in veterans with personality disorders. J Pers Disord. 2003;17:33–44.
  34. Black DW, Blum N, Letuchy E, et al. Borderline personality disorder and traits in veterans: psychiatric comorbidity, healthcare utilization, and quality of life along a continuum of severity. CNS Spectr. 2006;11:680–689.
  35. Reimherr FW, Williams ED, Strong RE, et al. A double-blind, placebo-controlled, crossover study of osmotic release oral system methylphenidate in adults with ADHD with assessment of oppositional and emotional dimensions of the disorder. J Clin Psychiatry. 2007;68:93–101.
  36. Langbehn DR, Pfohl BM, Reynolds S, et al. The Iowa Personality Disorder Screen: Development and preliminary validation of a brief screening interview. J Pers Disord. 1999;13:75–89.
  37. Ekselius L, Lindström E, von Knorring L, et al. SCID II interviews and the SCID Screen questionnaire as diagnostic tools for personality disorders in DSM-III-R. Acta Psychiatr Scand. 1994;90:120–123.
  38. Jacobsberg L, Perry S, Frances A. Diagnostic agreement between the SCID-II screening questionnaire and the Personality Disorder Examination. J Pers Assess. 1995;65:428–433.
  39. Klein MH, Benjamin LS, Rosenfeld R, et al. The Wisconsin Personality Disorders Inventory: I: Development, reliability, and validity. J Pers Disord. 1993;7:285–303.
  40. Benjamin LS. Interpersonal diagnosis and treatment of personality disorders, 2nd ed. New York, NY: The Guilford Press; 2002.
  41. Smith TL, Klein MH, Benjamin LS. Validation of the Wisconsin Personality Disorders Inventory-IV with the SCID-II. J Pers Disord. 2003;17:173–187.
  42. Robison RJ, Reimherr FW, Gale PD, et al. Personality disorders in ADHD part 2: the effect of symptoms of personality disorder on response to treatment with OROS methylphenidate in adults with ADHD. Ann Clin Psychiatry. 2010;22:94–102.

CORRESPONDENCE: Fred W. Reimherr, MD Mood Disorders Clinic, Department of Psychiatry, University of Utah Health Sciences Center, 30 N 1900 E Rm 5R218 Salt Lake City, UT 84132, USA E-MAIL: fred.reimherr@hsc.utah.edu