Participants
Among the 2606 participants in the survey, 2442 (93.70%) were included in the analyses after the missing data were excluded. Among these parents, 1343 were mothers/females and 1099 were males/fathers, and the mean age was 44.46 years (SD = 5.95). In addition, among these children and adolescents, 1168 were girls and 1274 were boys and the mean age was 11.20 years (SD = 2.54). Then, for the longitudinal survey used to examine the test-retest reliability of the J-DBDRS, 1566 participants were included in the analysis after the missing data were excluded.
Confirmatory factor analysis and reliability
Confirmatory factor analysis using WLSMV estimation were conducted to examine the four models of the J-DBDRS. The results showed the four-factor model was well fitted: χ2 = 2854.232, df = 733, GFI = 0.963, AGFI = 0.959, CFI = 0.967, NFI = 0.955, and RMSEA = 0.033 (90% CI: 0.032 to 0.035). Subsequently, for the factor loadings of each factor, sufficient values were found: 0.67 to 0.73 for 18 items for ADHD-IA, 0.53 to 0.71 for ADHD-HA, 0.61 to 0.76 for eight items for ODD, and 0.37 to 0.74 for CD. Strong positive correlations were found between ADHD-IA and ADHD-HA (r = .83), strong positive correlations between ADHD-IA and ADHD-HA, and ODD (r = .76 and r = .74, respectively), and moderate to strong positive correlations between CD and ADHD-IA, ADHD-HI, and ODD (r = .52, r = .64, and r = .67, respectively). The factor loadings and correlations between the factors are presented in Table 1. Internal consistency was then examined, and results showed high reliability for all subscales (ADHD-IA was α = .90, ADHD-HI was α = .85, ODD was α = .88, and CD was α = .88). The test-retest reliability of each subscale was examined and showed high reliability for ADHD-IA (r = .71, ICC (1, 2) = .83), ADHD-HI (r = .68, ICC (1, 2) = .81), and ODD (r = .69, ICC (1, 2) = .81). However, moderate reliability was observed for CD (r = .48, ICC (1, 2) = .64). In summary, the structural validity, internal consistency, and test-retest reliability of the J-DBDRS were confirmed.
Descriptive statistics of the DBDRS
To examine the differences according to gender and developmental stage, a two-factor analysis of variance was conducted. The results showed a significant main effect of gender on ADHD-IA and ADHD-HI scores (F (1, 2438) = 21.17, p < .001 and F (1, 2438) = 28.43, p < .001, respectively) and the symptoms of boys were higher than those of girls. Then, a significant main effect of stage on ADHD-IA, ADHD-HI, and ODD scores (F (1, 2438) = 33.44, p < .001; F (1, 2438) = 121.56, p < .001; and F (1, 2438) = 31.49, p < .001, respectively) and the symptoms of children were higher than those of adolescents. Besides, A significant interaction was found for AHHD-IA (F (1, 2438) = 4.00, p < .05), ADHD-HI (F (1, 2438) = 13.30, p < .01), and ODD (F (1, 2438) = 5.87, p < .05). The results of the post-hoc analyses indicated the symptoms were higher in children than in adolescents for boys and girls, and furthermore the symptoms were higher in boys than in girls among children (p < .05). The scores for each subscale and the results of the analysis of variance are presented in Table 2.
Estimated prevalence of ADHD, ODD, and CD
Then, the estimated prevalence of ADHD, ODD, and CD based on the DBDRS were calculated for six categories: ADHD-IA (inattention type), ADHD-HI (hyperactivity/impulsivity type), ADHD-COM (combined type), ADHD-ANY (any type), ODD, and CD. The results indicated that 2.70% for ADHD-IA, 0.37% for ADHD-HI, 1.06% for ADHD-COM, 4.14% for ADHD-ANY, 4.67% for ODD, and 1.68% for CD were shown, respectively. For ADHD-COM and ADHD-ANY, the estimated prevalence was higher in boys than in girls (p < .05; p < .01, respectively). For ODD, boys had a higher prevalence than girls (p < .01), and children had a higher prevalence than adolescents (p < .05). For CD, no significant differences in the estimated prevalence were observed between the genders and developmental stages. The prevalence of each diagnostic criterion and results of the χ2 test are shown in Table 3.
Correlation coefficient for each variable
To examine the construct validity of the DBDRS, correlation coefficients were calculated using the subscale and total SDQ-P scores. The results showed that ADHD-IA and ADHD-HI showed moderate-to-high positive correlations with hyperactivity/inattention on the SDQ (r = .66 and r = .56). Additionally, ODD and CD showed moderate-to-high positive correlations with the SDQ conduct problems (r = .70 and r = .60). Furthermore, general difficulties showed moderate-to-high positive correlations with ADHD-IA, ADHD-HI, ODD, and CD (r = .66, r = .60, r = .60, and r = .54, respectively). Thus, the convergent validity of the J-DBDRS was confirmed.
Association between disruptive behavior symptoms, anxiety, depression, and irritability
Hierarchical multiple regression analyses were conducted to identify the association between its symptoms, anxiety, depression, and irritability after controlling for gender, stage, and each symptom. The results indicated that ADHD-HI was moderately and positively related to ADHD-IA (β = 0.50), and ODD was weakly and positively related to ADHD-IA (β = 0.37). The results for ADHD-HI indicated that ADHD-IA was moderately and positively related to ADHD-HI (β = 0.47), and CD was weakly and positively related to ADHD-HI (β = 0.24). The results indicated that ADHD-IA was weakly and positively related to ODD (β = 0.27), and irritability was moderately and positively related to ODD (β = 0.53). The CD results indicated that the ADHD-HI was weakly and positively related to CD (β = 0.35). In summary, ADHD-IA and ODD were related, while ADHD-HI and CD were related. Additionally, irritability was related with ODD, but anxiety and depression were not related to any symptom of DBD after controlling for gender, stage, or other symptoms. The results of the hierarchical multiple regression analyses are presented in Table 4.