Adolescent disruptive behaviors
Both at T1 and T2, disruptive behavioral problems were assessed by the Child Behavior Checklist (CBCL), one of the most commonly used questionnaires in current child and adolescent psychiatric research [
52]. The CBCL contains a list of 120 behavioral and emotional problems, which parents can rate as 0 = not true, 1 = somewhat or sometimes true, or 2 = very or often true in the past six months. In most cases (96%), the informant was the child’s mother. In addition to the CBCL, we administered the self-report version of this questionnaire, the Youth Self-Report (YSR [
53]). In addition to the original CBCL/YSR scales, Achenbach and colleagues [
54] developed DSM-IV scales that corresponded more closely to clinical diagnostic categories. The scale for ODD comprises five items (Cronbach’s
α CBCL = 0.77, YSR = 0.62). The mean item score at T1 was 0.58 (
SD = 0.42, range 0–2) for the CBCL-scale and 0.44 (
SD = 0.35, range 0–1.8) for the YSR-scale. At T2 the mean item score was 0.42 (
SD = 0.39, range 0–2) for the CBCL-scale and 0.45 (
SD = 0.35, range 0–2) for the YSR scale. With a few exceptions, the percentages of (pre)adolescents endorsing each of the ODD symptoms ranged between 30% and 60%.
The DSM-IV scale for CD comprises 17 (CBCL) or 15 (YSR) items [
54]. From these, we selected 6 items (present in both questionnaires) as specifically reflecting ACD symptoms, that is, behaviors that violate the basic rights of others. These items were being cruel/mean to others, bullying, destroying things belonging to others, fighting a lot, physically attacking people, stealing outside the home, and threatening people. To ensure that these symptoms represented a different dimension than the ODD symptoms, factor analyses (two factors, promax rotation) were performed on the five ODD symptoms and the six ACD symptoms for each informant (parent, child) and measurement (T1, T2). Although the CBCL and YSR scores at T1 and T2 showed some relatively minor differences, the factor loadings generally reflected the assumed distinction between ODD and ACD. Table
1 shows the factor loadings based on the mean item scores across informants and measurements. The item ‘being cruel/mean to others’ had relatively high loadings on both factors. This is probably due to the fact that it had a relatively high prevalence, because of which part of its variance could not be explained by the other, more severe, ACD symptoms. The item was maintained in the selection of ACD symptoms because conceptually it is an evident example of behaviors that are harmful to others. The variance explained by the two factors was 51.2%. The mean item score at T1 was 0.09 (
SD = 0.18, range 0–1.7) for the CBCL-ACD scale and 0.14 (
SD = 0.22, range 0–1.5) for the YSR-ACD scale. At T2 the mean item score was 0.05 (
SD = 0.13, range 0–1.5) for the CBCL-ACD scale and 0.13 (
SD = 0.19, range 0–1.8) for the YSR-ACD scale. As indicated by the relatively low mean item scores, the prevalence of the ACD symptoms was considerably lower than that of the ODD symptoms, and the percentage of (pre)adolescents endorsing each of the ACD symptoms ranged between 37% to less than 2%. The reliabilities (Cronbach’s α) were 0.66 (T1 CBCL), 0.64 (T1 YSR), 0.64 (T2 CBCL), and 0.60 (T2 YSR).
Table 1
Two factor pattern matrix for oppositional defiant disorder (ODD) and aggressive conduct disorder (ACD) symptoms
ODD Argues a lot | .66 | |
Disobedient at home | .77 | |
Disobedient at school | .44 | |
Stubborn/irritable | .77 | |
Temper tantrums/hot temper | .48 | |
ACD Cruel/mean to others, bullying | .33 | .39 |
Destroys others’ belongings | | .51 |
Fights a lot | | .66 |
Physically attacks people | | .74 |
Steals outside the home | | .46 |
Threatens people | | .64 |
The agreement between parent-reported (CBCL) and adolescent-reported disruptive behavior (YSR) problems was moderate (T1: ODD r = .30, ACD r = .30; T2: ODD r = .35, ACD r = .33). The mean standardized parent and adolescent scores were used as a measure of ODD and ACD in this study. These measures correlated highly (≥.94) with the composite scores based on the highest (standardized) score of both informants. When CBCL/YSR data of one informant were missing or unreliable (missing YSRs: T1: n = 30, T2: n = 32; missing CBCLs: T1: n = 2, T2: n = 144), the composite score was based on only one informant.
Preschool behaviors
Preschool behaviors were assessed retrospectively by parents at T1, using the questionnaire ‘How was your child as a preschooler? (age 4–5)’. The questionnaire contains a list of 17 behavioral, emotional and motor items, which parents can rate on a five-point scale in relation to their child’s peers; 1 = a lot less than average, 2 = less than average, 3 = average, 4 = more than average, 5 = a lot more than average. Four items were selected as representing difficult preschool behaviors: hot temper, disobedience, bullying, and bossiness. Factor analysis (promax rotation) had revealed that these four behaviors made up a separate factor. We also constructed an overall preschool difficult behavior scale by averaging the items scores (Cronbach’s α = 0.70). The item ‘Was your child able to sense social situations well’ was used as a measure of the preschoolers social understanding. The term ‘social understanding’ is used in this paper to reflect a person’s ability to accurately perceive, interpret and grasp the nature of social interactions.