Concurrent Validity and Informant Agreement of the ADHD Module of the Anxiety Disorders Interview Schedule for DSM-IV

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1 J Psychopathol Behav Assess (2007) 29: DOI /s x ORIGINAL PAPER Concurrent Validity and Informant Agreement of the ADHD Module of the Anxiety Disorders Interview Schedule for DSM-IV Matthew A. Jarrett Jennifer C. Wolff Thomas H. Ollendick Published online: 19 October 2006 C Science+Business Media, LLC 2006 Abstract Examined the concurrent validity of the attentiondeficit/hyperactivity disorder (ADHD) module of the Anxiety Disorders Interview Schedule for DSM-IV, Child and Parent versions (ADIS-C/P). One hundred eighty-four clinic-referred children were categorized into three ADISgenerated groups: No diagnosis of ADHD (No ADHD; n = 63), parent-only diagnosis of ADHD (Parent Only; n = 81), and parent plus child diagnosis of ADHD (Parent + Child; n = 40). The groups were compared on demographics, comorbid diagnoses, parent and child-report measures, and a computerized test of attention. Results support the concurrent validity of the ADIS ADHD module and highlight the positive relationship between internalizing symptomatology and parent-child agreement on ADHD diagnoses. The clinical implication of this study is that parent-child agreement on ADHD may serve as a marker of internalizing symptomatology. Future research on child self-perceptions is suggested in developing treatments for this internalizing ADHD group. Keywords ADHD. Internalizing. Agreement Attention-deficit/hyperactivity disorder (ADHD) is one of the most common childhood psychiatric disorders and is estimated to affect 3% 5% of school age children (Buitelaar, 2002; Popper, 1988). Moreover, epidemiological studies of ADHD have found high rates of comorbid internalizing (13% to 51%) and externalizing disorders (43% to 93%), suggesting that pure or single disorders are the exception (Jensen, Martin, & Cantwell, 1997). In addition, M. A. Jarrett J. C. Wolff T. H. Ollendick ( ) Child Study Center, Department of Psychology, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060, USA tho@vt.edu these rates of comorbidity are often found to be even higher in clinic-referred children. Given the high rates of comorbidity in children with ADHD, it is important for diagnostic tools to accurately assess ADHD and other frequently occurring comorbid disorders in both research and clinical settings. Although rating scales and structured diagnostic interviews are frequently used in the diagnosis of ADHD (Biederman, Keenan, & Faraone, 1990; Pelham, Fabiano, & Massetti, 2005), they do not allow for clinical inquiry into the nature and severity of the disorder being evaluated. In response to this concern, semi-structured interviews have been developed that allow for a combination of the informant s report and the clinician s interpretation, which can be particularly helpful in the case of ADHD, since many of the diagnostic criteria of ADHD involve somewhat normative childhood behaviors (e.g., inattention, trouble listening, staying in seat). Semi-structured interviews also allow the clinician to determine the degree of correspondence between the presenting symptoms and the criteria of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV; American Psychiatric Association, 1994; see Doss, 2005, and Hodges, 1993). Recent advances in these semi-structured diagnostic interviews have resulted in the development of interviews tailored to specific childhood disorders. One example of such an interview is the Anxiety Disorders Interview Schedule for DSM-IV, Child and Parent versions (ADIS-C/P; Silverman & Albano, 1996). The ADIS-C/P was designed primarily to assess anxiety and its disorders, but it has also been used to assess a variety of co-occurring childhood disorders, including the mood disorders and the disruptive behavior disorders. Although the ADIS-C/P has exhibited impressive psychometric properties in the assessment of anxiety disorders (see Wood, Piacentini, Bergman, McCracken, & Barrios, 2002), the validity of the ADHD module of the ADIS-C/P has not yet been

2 160 J Psychopathol Behav Assess (2007) 29: determined. This evaluation is particularly important since this instrument is widely used in clinical settings (Silverman & Ollendick, 2005) and often used to assess comorbid disorders. In the case of ADHD, research has found that between 25% and 50% of clinic-referred children exhibit both an anxiety disorder and ADHD (Biederman, Newcorn, & Sprich, 1991). Given this high rate of comorbidity and the use of the ADIS-C/P in many clinics, the validity of the ADHD module of the ADIS-C/P has important clinical and research implications. Thus, the first question addressed in the current study was whether the ADHD module of the ADIS-C/P is concurrently valid. In addition to the validity concerns, the ADIS-C/P ADHD module has not been evaluated in terms of parent-child agreement. Over the past few decades, researchers have recommended a multi-informant assessment to obtain a complete diagnostic picture of the child (Ollendick & Hersen, 1993). Unfortunately, the inclusion of child information has posed significant problems, as researchers have reported significant disagreement among child, parent, and teacher informants (De Los Reyes & Kazdin, 2005; Grills & Ollendick, 2002; Jensen et al., 1999). In relation to the ADIS-C/P, studies have found poor or variable parent-child agreement across specific disorders, but agreement on the anxiety disorders has been somewhat higher than other disorders (Grills & Ollendick, 2003; Rapee, Barrett, Dadds, & Evans, 1994). Given the discrepancies between parents and children, evaluation of parent-child agreement on the ADHD module of the ADIS-C/P could be valuable in understanding the nature and severity of ADHD and its co-occurring disorders (McGrath, Handwerk, Armstrong, Lucas, & Friman, 2004; Volpe, DuPaul, Loney, & Salisbury, 1999). Although parentchild agreement on the ADHD module of the ADIS-C/P has not been explored, it has been examined on the Diagnostic Interview Schedule for Children (DISC; Costello, Edelbrock, Kalas, Kessler, & Klaric, 1982), another diagnostic interview that is frequently used in clinical settings. Among children rated by parents as having elevated Attention Problems on the Child Behavior Checklist (CBCL), Volpe et al. (1999) found that children who met diagnostic criteria for ADHD on the child DISC (in agreement with their parents) endorsed significantly more anxiety and depression symptoms than children who did not endorse an ADHD diagnosis. In a more recent analysis of parent-child agreement on the DISC ADHD module in adolescents (ages 12 to 17), McGrath et al. (2004) reported a similar trend when comparing a parent plus child ADHD group to a parent only ADHD group. In a similar vein, the second question addressed in the current study was related to differences between parent only and parent plus child ADHD diagnostic groups as determined by the ADIS-C/P. In summary, the present study sought to examine the concurrent validity of ADHD diagnoses generated from the ADIS-C/P by comparing interview results to parent and teacher checklists, child self-report measures, and a computerized test of attentional functioning, the Conners Continuous Performance Test (CPT; Conners, 1994). The following groups were created based on diagnostic information obtained from both parent and child ADIS interviews: No diagnosis of ADHD by either informant (No ADHD), parent-only diagnosis of ADHD (Parent Only), and parent plus child diagnosis of ADHD (Parent + Child). In an attempt to replicate past results, the study utilized measures that have been used in past studies but also included a recently developed child-report measure of anxiety (i.e., Multidimensional Anxiety Scale for Children, see below). It was hypothesized that both the Parent Only and the Parent + Child groups would score higher on ADHD-related measures (i.e., CBCL Attention Problems, CPT indices) in comparison to the No ADHD group, supporting the concurrent validity of the ADIS. Moreover, consistent with findings reported for ADHD children using the DISC (McGrath et al., 2004; Volpe et al., 1999), it was hypothesized that greater parent-child agreement on ADHD would be associated with the presence of co-occurring internalizing symptoms and disorders. Methods Participants Children and their parent(s) presented at an outpatient clinic in southwestern Virginia for a comprehensive psychoeducational assessment. Children were referred by community pediatricians, family practitioners, schools, and mental health professionals. One clinician interviewed the parent(s) and administered the parental measures described below while a second clinician separately and independently completed the child assessment. Children were seen for three assessment sessions, which included intellectual and achievement testing, a clinical interview, and several selfreport and laboratory measures in addition to the ADIS-C/P. Institutional Review Board approval was obtained. Participants included 184 children (mean age = 10.69; SD = 2.53; range = 8 16 years) and their parent(s). 117 of the children were boys (63.6%) and 67 were girls (36.4%). The majority was Caucasian (93.7%) and primarily from lower middle class and middle class backgrounds. The mean income for the sample was $45,961 (SD = $36,667). The vast majority of parents (90.6%) had graduated from high school. Among the 121 children diagnosed with ADHD, 46 (38%) met diagnostic criteria for the inattentive type while 75 (62%) met criteria for the combined type. The Parent Only group included 33 (41%) children diagnosed with the inattentive type and 48 (59%) with the combined type, while the Parent + Child group included 13 (32%) diagnosed

3 J Psychopathol Behav Assess (2007) 29: Table 1 Mean/count and standard deviation/percentage for demographic and diagnostic characteristics Parent + child (N = 40) Parent only (N = 81) No diagnosis (N = 63) Test Boys 25 (63) 51 (63) 41 (65) χ 2 (2) =.10 Age (2.65) (2.37) (2.63) F(2) = 1.59 Full scale IQ (12.00) (12.90) (13.60) F(2) = 1.06 ADHD Medications (stimulants and atomoxetine) 12 (30) a 28 (35) a 5(8) b χ 2 (2) = ADHD Inattentive 13 (33) 33 (41) 0 (0) None ADHD Combined 27 (68) 48 (59) 0 (0) None Anxiety 16 (40) 31(38) 19 (30) χ 2 (2) = 1.39 Mood 2 (5) 8 (10) 8 (13) χ 2 (2) = 1.64 Conduct problems 9 (23) 27(33) 12 (19) χ 2 (2) = 4.09 Learning disorder 10 (25) 28 (35) 19 (30) χ 2 (2) = 1.23 Note. Letters in superscript indicate statistically significant differences between groups (p <.05). with the inattentive type and 27 (68%) with the combined type. ADHD subtypes did not differ between the two ADHD groups. Given the limited number of hyperactive subtype children in the sample (n = 4), these children were excluded from subsequent analyses. Of the 63 children and adolescents in the No ADHD group, 19 (30%) did not meet criteria for any diagnosis (even though they were clinically referred) while 44 (70%) met criteria for at least one diagnosis (but not ADHD). Overall, 79% of the sample was comorbid with two or more disorders. In terms of medication usage, 45 of the 121 children who met criteria for ADHD were receiving ADHD medications (i.e., stimulants or atomoxetine) at the time of referral. 1 Table 1 presents the medications prescribed for each group along with other descriptive variables of interest. Procedure The sample of 184 children was drawn from a larger sample of 307 children who were seen at the clinic. Several inclusion and exclusion criteria were used to arrive at the final sample of 184 children. First, those children between the ages of 8 and 16 who had an ADHD diagnosis (based on the ADIS-C/P; see below for criteria) or did not have an ADHD diagnosis were retained in the study sample. The sample was restricted to this age range to correspond with the age range reported for valid use of the ADIS-C/P and other instruments used in this study. Second, those children having a Full Scale IQ less than 80 (n = 42) as assessed by the WISC-III or WISC-IV were excluded from the sample due to cognitive requirements associated with completing the various self-report measures. Finally, those children having a consensus diagnosis of either childhood schizophrenia (n = 3) or a pervasive developmental disorder (n = 23) were excluded from the study. 1 Parents were asked to discontinue stimulant medications (not including the non-stimulant atomoxetine) for their child (if applicable) on the days of assessment. As noted earlier, participants were categorized into three groups based on diagnoses generated from the ADIS-C/P interview. A diagnosis was considered present if the clinician s severity rating was 4 or higher on a 0 8 rating scale, as recommended by Silverman and Albano (1996). The groups were the following: No ADHD diagnosis reported by either informant (No ADHD; n = 63), ADHD reported by the parent but not the child (Parent Only; n = 81), and ADHD reported by both the parent and the child (Parent + Child; n = 40). A Child Only group was also examined, but due to the small sample size (n = 6), this group was excluded from further analyses. As indicated by these assignments, about two-thirds of the ADHD sample received Parent Only ADHD diagnoses whereas one-third received Parent + Child ADHD diagnoses, indicating that children tended not to agree with their parents on the presence of an ADHD diagnosis. This finding is consistent with past research on parent-child agreement on the ADIS-C/P (Grills & Ollendick, 2003). Measures Anxiety Disorders Interview Schedule for DSM-IV, Child and Parent Versions (ADIS-C/P; Silverman & Albano, 1996). The ADIS-C/P versions are semi-structured interviews designed for the diagnosis of most psychiatric disorders seen in childhood and adolescence. During the interview, the clinician assesses symptoms and obtains frequency, intensity, and interference ratings (0 8 scale). These symptoms and ratings are used by the clinician to identify diagnostic criteria and develop a clinician s severity rating (CSR). A CSR of 4 or above (0-8) indicates a diagnosable condition. It should be noted that the ADIS assesses for Conduct Disorder (CD) and Oppositional-Defiant Disorder (ODD) in the parent interview only (see below). Recent examination of the ADIS-C/P (for DSM-IV) has yielded acceptable to excellent 7 to 14-day test-retest

4 162 J Psychopathol Behav Assess (2007) 29: reliability estimates regarding child (ages 7 16; κv =.61.80) and parent (κ = ) diagnoses for those diagnoses assessed on the ADIS (Silverman, Saavedra, & Pina, 2001). Interrater agreement analyses of earlier versions of the ADIS- C/P have shown some variability in video (κ =.45.82; Rapee et al., 1994) and live observer paradigms (κ = ; Silverman & Nelles, 1988), but in general, acceptable interrater agreement has been established, again for all specific diagnoses assessed by the ADIS. Trained graduate-student clinicians who were enrolled in an American Psychological Association-approved doctoral program in clinical psychology conducted the diagnostic interviews. All clinicians were blind to the purposes of the study and all interviews were videotaped. Interrater reliability was calculated from these videotapes for randomly selected child (n = 20) and parent (n = 36) cases. Acceptable levels of interrater agreement were found for both the child (κ =.71) and parent (κ =.77) interviews across the various diagnoses (Grills & Ollendick, 2003). Child Behavior Checklist (CBCL; Achenbach, 2001a). The CBCL is a 113-item paper and pencil questionnaire completed by parents. Parents are asked to indicate how often the behavior described in each item is true of their child using a three-point scale (often/always true, sometimes true, and not true). Achenbach (2001a) reports test-retest reliability over a 1-week interval to be.95 for the problem items. The validity of the CBCL/4 18 has been established through repeated factor analyses and associations with other variables of interest (see Achenbach, 2001a). Only maternal report was used for the current study, given that almost all primary parents were mothers (181 of 184, 98%) in the current sample. Teacher Report Form (TRF; Achenbach, 2001b). The TRF is a questionnaire that includes 113 items to which the teacher is asked to indicate if each behavior/characteristic is often/always true, not true, or sometimes true of the student being assessed. Test-retest reliability over a 15-day period is.90 for the adaptive behavior scales and.95 for the problem behavior scales (see Achenbach, 2001b). Multidimensional Anxiety Scale for Children (MASC; March, Parker, Sullivan, Stallings, & Conners, 1997). The MASC is a 45-item self-report questionnaire designed for children between 8 and 16 years of age. For each item, the child is asked to endorse one of four responses (i.e., never true, rarely true, sometimes true, often true). This is a psychometrically sound instrument with high test-retest reliability, high internal consistency, and acceptable convergent and discriminant validity (March et al., 1997; March & Sullivan, 1999). Main and subfactor scores include (1) Physical Symptoms (Tense/Restless and Somatic/Autonomic), (2) Social Anxiety (Humiliation/Rejection and Public Performance Fears), (3) Harm Avoidance (Perfectionism and Anxious Coping), and (4) Separation Anxiety. A total anxiety score, an anxiety disorders index, and an inconsistency index are also obtained. Revised Children s Manifest Anxiety Scale (RCMAS; Reynolds & Richmond, 1985). The RCMAS is a 37- item, true-false, child-report measure designed to evaluate anxiety in children and adolescents. The RCMAS generates a total anxiety score as well as three subscales: Physiological Anxiety, Worry/Oversensitivity, and Social Concerns/Concentration. The RCMAS also contains a lie scale to assess response bias toward social desirability. Adequate psychometric properties have been established for this instrument (Cole, Peeke, Martin, Truglio, & Seroczynski, 1998). Children s Depression Inventory (CDI; Kovacs, 1985). The CDI is a 27-item child self-report questionnaire assessing symptoms of depression. For each item, the child is asked to choose among three statements representing varying levels of symptomatology. The CDI yields a total score and five subscale scores: Negative Mood, Interpersonal Problems, Ineffectiveness, Anhedonia, and Negative Self-Esteem. Smucker, Craighead, Craighead, & Green (1986) found adequate reliability for the CDI in both boys and girls across several age groups (α =.83to.89). Conners Continuous Performance Test (CPT; Conners, 1994) The CPT is a vigilance task lasting approximately 14 minutes in which respondents are asked to press the space bar when any letter other than X appears on the computer screen. The test has shown to be a reliable task in the assessment of ADHD, using the criteria of at least three independent investigators finding significant between-group (i.e., ADHD vs. control) differences in at least 75% of studies (Rapport, Chung, Shore, Denney, & Isaacs, 2000). The major variables of interest for this study include the overall index, omission errors, commission errors, and hit rate. The overall index score indicates attention problems derived from a weighted regression equation of variables relevant to reaction time, omission errors, and variability of responses. An overall index score greater than 11 is considered the cutoff for attention problems, so children who score higher than 11 are considered to have failed the CPT (Conners, 1994). It should be noted that examiners either stayed in the room or watched the child s performance from the observation room. If a child started to get off task, the examiner redirected the child and if necessary went into the room to facilitate maximal performance. Wechsler Intelligence Scale for Children (WISC; Wechsler, 1991, 2003). The WISC is an individually administered clinical instrument for assessing the intellectual ability of children aged 6 years through 16 years and 11 months. The mean score for the Full Scale IQ (FSIQ) is 100 with a standard deviation of 15. Evidence for adequate

5 J Psychopathol Behav Assess (2007) 29: reliability and validity of the WISC has been documented (Wechsler, 1991; Prifitera, Saklofske, & Weiss, 2005). Given the timeframe of the study, which extended over several years, the WISC-III (1991) and WISC-IV (2003) were used to assess intellectual ability. Wechsler Individual Achievement Test (WIAT; The Psychological Corporation, 1992, 2002). The WIAT is a comprehensive, individually administered test for assessing the achievement of children, adolescents, college students, and adults who are between 4 and 85 years of age. It provides an assessment of the individual s level of achievement in four basic content domains: Reading, Mathematics, Written Language, and Oral Language. The psychometric properties of the WIAT have been documented (The Psychological Corporation, 1992). The data used for the present study include the WIAT as well as the WIAT II (The Psychological Corporation, 2002), a revised version of the original test. Data analysis Data were analyzed for all participants who met inclusion criteria. Missing data were handled using listwise deletion by measure. A number of teachers did not return the TRF, so the number of subjects varied for some analyses. 33 of 40 (83%) teachers returned the measure in the Parent + Child group. 62 of 81 (77%) teachers returned the measure in the Parent Only group. Finally, 39 of 63 (62%) teachers returned the measure in the No ADHD group. Return rates did not differ by group. Analyses undertaken included chisquare (χ 2 ) analyses for categorical data and Analysis of Variance (ANOVA) and Multivariate Analysis of Variance (MANOVA) for continuous data. Results As shown in Table 1, no significant differences were found among the three ADIS-C/P groups on basic demographic measures. χ 2 analyses revealed that the groups did not differ significantly on gender. Nor did they differ on income, classified according to four categories ( < $25,000, $25,000 $49,999, $50,000 $74,999, > $75,000). Moreover, one-way ANOVAs failed to show group differences on age or Full Scale IQ. Significant differences, however, were revealed among groups on prescribed ADHD medication, as expected, with bivariate χ 2 analyses showing that those in the No ADHD group had been prescribed significantly less ADHD medications than those in the Parent Only (χ 2 (1) = 14.23, p.01) and Parent + Child groups (χ 2 (1) = 8.64, p.01), who did not differ from one another. As also can be seen in Table 1, significant differences were not revealed in rates of comorbid disorders among the three groups. Comorbid disorders were categorized in the following way: Anxiety (Generalized Anxiety Disorder, Separation Anxiety Disorder, Social Phobia), Mood (Dysthymia, Major Depressive Disorder), Conduct Problems (Conduct Disorder, Oppositional Defiant Disorder), and learning disorders (any type). A learning disorder was defined as a 23-point difference between ability (WISC-III or IV) and achievement (WIAT or WIAT II) test scores, combined with evidence of clinically elevated impairment of functioning. A comorbid disorder was considered present if the child was assigned a clinical diagnosis during a consensus meeting utilizing multiple measures and multiple informants (see Grills & Ollendick, 2003 for details). The consensus meeting was chaired by a clinical child psychologist with 35 years of clinical experience, as well as the child and parent clinicians who conducted the ADIS-C/P interviews. No significant differences were found among the three groups for comorbid Anxiety, Mood, Conduct Problems, and learning disorders. In order to assess the concurrent validity of the ADIS- C/P ADHD module, multivariate and univariate analyses were performed on measures related to ADHD and its correlates. Means, standard deviations, and F values are presented in Table 2. On the CBCL, the Internalizing, Externalizing, and Attention T-Scores were significantly different among groups according to MANOVA (F(6,330) = 9.30, p.01). Post-hoc analyses demonstrated that the two ADHD groups, which did not differ from one another, showed greater Externalizing and Attention Problems than the No ADHD group. In addition, the two ADHD groups did not differ from one another on the Internalizing Problems scale; however, the Parent Only group showed significantly greater Internalizing Problems than the No ADHD group whereas the Parent + Child group did not. Although this latter finding was not significant, visual inspection of the data suggests that both the Parent Only and Parent + Child groups showed greater parent-reported internalizing symptoms than the No ADHD group. On the TRF, a MANOVA conducted on the Internalizing, Externalizing, and Attention T-scores showed significant differences among groups (F(2,258) = 2.92, p =.01). Posthoc analyses demonstrated that the two ADHD groups evidenced more Attention Problems than the No ADHD group. Significant differences were also found among groups for Externalizing Problems, but post-hoc analyses failed to reveal significant differences between particular groups. Visual inspection of the data suggested that the Parent + Child group had higher externalizing symptomatology than the other groups. No differences among groups were found for the Internalizing scale. On the CPT, univariate analyses on the overall index score indicated that scores were significantly different among groups with post-hoc analyses showing that the two ADHD groups evidenced significantly more attentional problems

6 164 J Psychopathol Behav Assess (2007) 29: Table 2 Means, standard deviations, and tests comparing parent + child, parent only, and no ADHD diagnosis groups on parent report, teacher report, and the computerized test Parent + Child (N = 38) Parent Only (N = 77) No ADHD (N = 55) CBCL F Sig Effect size (η 2 ) Internalizing (9.96) a,b (10.68) a (13.96) b Externalizing (10.03) a (9.94) a (13.84) b Attention (8.32) a (8.13) a (9.08) b < TRF Parent + Child (N = 33) Parent Only (N = 62) No ADHD (N = 39) F Sig Effect size (η 2 ) Internalizing (10.85) (11.58) (8.93) Externalizing (8.49) (11.18) (10.65) Attention (10.41) a (8.50) a (6.46) b 6.31 < CPT Parent + child (N = 40) Parent only (N = 79) No ADHD (N = 60) F Sig Effect size (η 2 ) Hits (23.02) (52.62) (38.79) Omissions (23.02) (52.62) (38.79) Commissions (5.92) (8.13) (8.17) Overall Index (8.47) a (7.30) a 8.00 (6.84) b Note. CBCL: Child Behavior Checklist; TRF: Teacher Report Form; CPT: Conners Continuous Performance Test. Letters in superscript indicate statistically significant differences between groups (p <.05). Cohen (1988) recommends the following interpretation of η 2 : small:.01 to.05, medium:.06 to.13, large:.15 or greater. than the No ADHD group. A MANOVA was also conducted on omissions, commissions, and hits; however, no significant differences were found among the three groups on these more discrete measures (F(2,350) = 1.27, p =.28). In order to examine the relationship between parentchild agreement and depressive and anxious symptoms, MANOVAs were performed on the subscales of the childreport measures. Means, standard deviations, and F values are presented in Table 3. The multivariate analysis of the CDI subscales (F(10,340) = 2.90, p.01) revealed significantly higher self-reported depression in the Parent + Child group compared to the No ADHD and Parent Only groups. Post-hoc analyses showed that the Parent + Child group reported greater Negative Mood, Ineffectiveness, Anhedonia, and Negative Self-Esteem problems than the other two groups. On the RCMAS, a multivariate analysis conducted on the subscales of this measure showed differences among groups (F(6,330) = 2.68, p =.02), as the Parent + Child group reported significantly higher rates of anxiety in comparison to the Parent Only and No ADHD groups. Post-hoc analyses found that the Parent + Child group reported greater Physiological Anxiety, Worry/Oversensitivity, and Concentration than the other two groups. Finally, an ANOVA was conducted on the Lie Scale of the RCMAS, but no significant differences were found among groups. On the MASC, a multivariate analysis of the subscales showed significant differences among groups (F(6,328) = 4.80, p.01), as the Parent + Child group reported significantly greater anxiety than the other two groups. In addition, post-hoc analyses on the subscales indicated that the Parent + Child group reported greater Physical Symptoms and Social Anxiety than the other two groups. Finally, an ANOVA conducted on the Inconsistency Index revealed that the groups did not differ on this dimension. 2 Discussion The current study sought to examine the concurrent validity of the ADIS using a parent-child agreement framework. It was hypothesized that both the Parent Only and the Parent + Child groups would score higher on ADHD-related measures (i.e., CBCL Attention Problems, CPT indices) in comparison to a No ADHD group, supporting the convergent validity of the ADIS. Moreover, it was hypothesized that the presence of co-occurring internalizing disorders and symptomatology would be associated with greater parent-child agreement. Such effects would be consistent with findings reported for ADHD children using the DISC (McGrath et al., 2004; Volpe et al., 1999). 2 Since medication status and age were thought to affect agreement, all analyses were rerun controlling for these variables. Analyses were also rerun on all measures removing children with the inattentive subtype of ADHD. Significance findings were not altered for these analyses. An analysis on the inattentive type alone was not conducted due to insufficient sample size. These findings are available from the authors upon request.

7 J Psychopathol Behav Assess (2007) 29: Table 3 Means, standard deviations, and tests comparing parent + child, parent only, and no ADHD diagnosis groups on child report measures CDI Parent + child Parent Only No ADHD F Sig Effect size (η 2 ) (N = 39) (N = 78) (N = 60) Neg. Mood (14.03) a (9.49) b (9.00) b < Interpersonal (12.14) (11.05) (9.64) Ineffectiveness (11.26) a (11.34) b (9.88) b 8.61 < Anhedonia (11.60) a (10.67) b (9.04) b 8.41 < Self-Esteem (13.15) a (8.18) b (7.85) b 4.57 < RCMAS Parent + Child (N = 36) Parent Only (N = 74) No ADHD (N = 60) F Sig Effect Size (η 2 ) Phys. Anxiety (12.14) a 9.58 (3.48) b 8.85 (2.80) b 7.96 < Worry (13.55) a 8.77 (3.86) b 8.10 (3.22) b 5.84 < Concentration (13.66) a 9.46 (3.02) b 8.50 (2.77) b 6.45 < Lie Scale 9.36 (3.90) 9.39 (3.00) 9.92 (2.79) MASC Parent + Child (N = 39) Parent Only (N = 71) No ADHD (N = 59) F Sig Effect Size (η 2 ) Physical (12.23) a (12.67) b (9.30) b < Harm Avoid (11.37) (11.94) (13.42) Social Anx (11.74) a (12.61) b 45.75(10.11) b < Inconsistency 6.21 (3.39) 6.06 (3.20) 5.05 (2.39) Note. CDI: Children s Depression Inventory; RCMAS: Revised Children s Manifest Anxiety Scale; MASC: Multidimensional Anxiety Scale for Children; Letters in superscript indicate statistically significant differences between groups (p <.05). Cohen (1988) recommends the following interpretation of η 2 : small:.01 to.05, medium:.06 to.13, large =.15 or greater. Overall, results support the validity of the ADHD module of the ADIS-C/P. Parents who endorsed ADIS-C/P criteria for ADHD in both ADHD groups reported significant problems in ADHD-relevant functioning on the CBCL (i.e., Attention Problems) as did the teachers of these children on the TRF. Moreover, although the groups did not differ on a subset of CPT variables, children in both ADHD groups showed greater impairment on the CPT overall index score. The lack of significant differences on the subset of CPT variables was unexpected, as children with ADHD have been found to exhibit higher scores on hits, commissions, and omissions than healthy control children (Frazier, Demaree, & Youngstrom, 2004). It should be noted, though, that the current study utilized a clinical control group rather than a healthy group for comparison, and differences between ADHD and clinical control groups have not always been found (Matier-Sharma, Perachio, Newcorn, Sharma, & Halperin, 1995). Finally, the Parent + Child group did not differ from the Parent Only group on the severity of Attention Problems on the CBCL or TRF, nor on the CPT. Thus, findings from this study do not support the notion that informant agreement may be a marker of ADHD severity. In relation to co-occurring symptomatology, no significant differences were found among groups for Anxiety, Mood, Conduct Problems, and learning disorders. This nonsignificant finding was unexpected, since it was hypothesized that children in the Parent + Child group would exhibit more internalizing disorders. Although differences were not found at the diagnostic level, differences were found at the symptom level, as children in the Parent + Child group reported more internalizing symptoms on self-report measures relative to the other two groups. This finding was obtained for two child anxiety measures (MASC, RCMAS) and a measure of childhood depression (CDI). One exception to this symptom-level pattern of findings for the Parent + Child group on internalizing symptoms was the significant difference between the Parent Only, but not the Parent + Child group, and the No ADHD group on parent-reported internalizing symptoms on the CBCL. This finding was unexpected, and it is not clear why this group had a higher level of parent-reported internalizing problems. Still, visual inspection of the data suggests that both the Parent Only and Parent + Child groups showed greater parent-reported internalizing symptoms than the No ADHD group, which may suggest that parents see their ADHD child as having problems related to ADHD (e.g., internalizing symptomatology) regardless of agreement status. Possible explanations for elevated child-reported internalizing symptoms in the Parent + Child group include a general tendency for these children to overendorse psychopathology, social desirability in their responding, or accumulated internalizing symptoms resulting from the effects

8 166 J Psychopathol Behav Assess (2007) 29: of ADHD over time (e.g., peer rejection and academic failure). The first hypothesis is not supported by the current findings, as children did not overendorse symptomatology across all subscales. For example, although children in the Parent + Child group reported more symptoms on a number of domains of depression on the CDI, they did not endorse Interpersonal Problems more often than the Parent Only group. Similarly, children in the Parent + Child group did not report heightened anxiety in all domains on the MASC. In relation to social desirability as a second possible explanation for these findings, the two ADHD groups did not differ on the RCMAS Lie Scale or the MASC Inconsistency Index, suggesting that social desirability did not affect the results. In relation to the third hypothesis, children in the Parent + Child group displayed more Negative Self-Esteem and Ineffectiveness on the CDI, suggesting that the selfconcepts of children in this group may have been affected more adversely by the presence of ADHD. Interestingly, the two ADHD groups did not differ on age; thus, the development of internalizing symptoms in ADHD children appears not to be simply a function of age or the duration of the disorder. In relation to past studies, the findings from Volpe et al. (1999) with the DISC are largely consistent with the current study. In the Volpe et al. (1999) study, the children showed elevations on all three of the RCMAS factors, as they did in the current study. On the CDI, however, their child participants only showed elevations on Negative Mood, Ineffectiveness, and the CDI Total Score. The current results replicate their findings, and extend them by reporting elevations on the Anhedonia and Negative Self-Esteem subscales as well. It should be noted that children in the Volpe et al. (1999) study were considerably younger (ages 6 to 10) than children in the current study (average age of nearly 11). It may be that children in the current sample had additional time to experience the academic and social failure that is common for children with ADHD as they progress into middle childhood and adolescence. Such additional failure experiences may have led to lower levels of self-esteem and less enjoyment of activities. It should be noted that neither study found significant differences for Interpersonal Problems. It may be that this area becomes more prominent in adolescence, as ADHD deficits come to interfere with the development of more sophisticated peer relationships, a crucial developmental task during this age period. Alternatively, the lack of a difference may be related to the inability of ADHD children to recognize the effect of their behavior on their social relationships (Hoza, Pelham, Dubbs, Owens, & Pillow, 2002). Limitations of the current study include a local and clinical sample that included only a small percentage of minority families and girls. In addition, although a large sample was enlisted, the relatively small number of children with the inattentive subtype of ADHD, and an even smaller number of children with the hyperactivity subtype, precluded the opportunity to explore these groups in more detail. This type of analysis would have been valuable, especially for the inattentive subtype, since research has indicated that this subtype shows greater comorbidity with internalizing disorders (Barkley, DuPaul, & McMurray, 1990). Another limitation might be associated with the manner in which the ADIS-C/P interviews were administered in the current study. Silverman & Albano (1996) suggest that the same clinician should interview both the child and parent(s) with the child interview usually conducted first. The current study utilized two different clinicians when administering the interviews, such that each was blind to the other interview. It seems possible that the method advocated by Alabano and Silverman would lead to biases in conducting the second interview. For example, it seems likely that the clinician might unintentionally influence the process of the parent interview through direct (e.g., additional probing) or indirect (e.g., tonal change in voice, facial expressions) means. Although the current method of administering the interviews may have affected the findings, it seems that the current method would lead to less bias in true parentchild agreement. In addition, this method has been adopted by other research groups using the ADIS-C/P (Comer & Kendall, 2004; Rapee et al., 1994). Additional limitations were noted with some of the measures used in the study. Although the CBCL Attention Problems scale and CPT served as measures of convergent validity, other measures such as rating scales that involve DSM-IV criteria for ADHD would have been ideal. Unfortunately, such measures were not collected in the current study. Another limitation in relation to the current scales is the fact that the behavior of some children was rated while they were on medication and hence their behavior might have been under better control. This issue is problematic in most studies of ADHD children or other children who are medicated for other problems. To control for this effect, future studies might ask informants to rate their child at times when they are off medications (e.g., weekends, summers). Still, even this strategy might result in biased or distorted recollections. The clinical implication of these findings is that the ADIS is a concurrently valid instrument not only for the anxiety disorders but also for ADHD. In addition, when a parent and a child agree on the presence of ADHD, the findings suggest that the child may also possess internalizing problems. Although the groups in this study did not differ on comorbid internalizing disorders, the groups did differ on child-reported internalizing symptoms. Given that the children in the current sample were in middle childhood (mean age = years), it may be that children who agree with their parents on the presence of ADHD are starting to become cognizant of the effects that their attentional problems are having on their lives. Based on the current findings, clinicians might further

9 J Psychopathol Behav Assess (2007) 29: probe for internalizing problems when a parent and child agree on the presence of ADHD. In relation to treatment, the current frontline treatment for children with ADHD is stimulant medication, as behavioral interventions alone have proven to be less effective (MTA Cooperative Group, 1999a). At the same time, the large-scale, NIMH-funded Multimodal Treatment Study of ADHD (MTA Study) found that children with comorbid anxiety benefited more from behavioral treatment than non-comorbid children (MTA Cooperative Group, 1999b). Although speculative, it may be that ADHD children with a comorbid internalizing disorder or internalizing symptomatology would benefit more from behavioral interventions due to the awareness they have of their deficits or their enhanced ability to self-monitor their behavior. In relation to future treatments for this internalized ADHD group, an examination of self-perceptions may also be valuable to consider. Children with ADHD have been found to have a positive illusory bias, resulting in an overestimation of their abilities or a diminished perception of their deficits (Hoza et al., 2002). This bias may serve as a buffer to the development of internalizing problems, as such children may fail to recognize the effects of the disorder on their academic achievement and social relationships. The results from the current study suggest that children with comorbid internalizing symptoms are more aware of their ADHD-related deficits. Although speculative, it may be that the presence of internalizing symptoms attenuates the positive illusory bias in ADHD children which may help them understand the effect that their behavior has on their performance. The salience of this impairment may help to motivate ADHD children with internalizing problems to regulate their behavior more effectively, which in turn, could potentially make behavioral and cognitive interventions more effective. 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