| Non-responders (N = 343) | Study participants (N = 679) | Test-statistic (Missing analyses) | Boys (N = 326, 48.01%) | Girls (N = 353, 51.98%) | Test-statistic (Boys vs. girls) |
---|---|---|---|---|---|---|
Age M, (SD) year | 15.50 (0.93) | 14.77 (0.81) | Z = − 11.64** | 14.78 (0.78) | 14.75 (0.85) | Z = − 0.65 |
Educational level (N, %) |  |  | χ2 = 26.43** |  |  | χ2 = 5.50 |
 Special needs/prevocational | 164 (47.8) | 303 (44.6) |  | 136 (41.8) | 167 (47.3) |  |
 Higher general | 62 (18.0) | 157 (23.1) |  | 73 (22.4) | 84 (23.8) |  |
 Pre-university | 31 (9.0) | 155 (22.8) |  | 81 (24.8) | 74 (21.0) |  |
 Combined | 29 (8.4) | 59 (8.7) |  | 34 (10.4) | 25 (7.1) |  |
Monthly Household income (N, %) |  |  | χ2 = 44.49** |  |  | χ2 = 11.42 |
 € < 1600 | 52 (15.1) | 56 (8.2) |  | 25 (7.6) | 31 (8.8) |  |
 €1600–2400 | 39 (11.3) | 99 (14.5) |  | 40 (12.3) | 59 (16.7) |  |
 €2400–4399 | 101 (29.4) | 333 (49.0) |  | 160 (49.1) | 173 (48.9) |  |
 € > 4400 | 44 (12.8) | 149 (21.9) |  | 79 (24.2) | 69 (19.5) |  |
Ethnic Origin (N, %) |  |  | χ2 = 49.76** |  |  | χ2 = 6.73 |
 Dutch N, (%) | 169 (49.2) | 540 (79.5) |  | 257 (78.8) | 283 (80.2) |  |
 Other western | 14 (4.0) | 41 (6.0) |  | 19 (5.8) | 22 (6.2) |  |
 Non-western | 73 (21.3) | 78 (11.4) |  | 38 (11.5) | 59 (11) |  |
Callous Unemotional traits M (SD) | - | 15.59 (7.82) |  | 17.71 (7.99) | 13.66 (7.15) | Z = − 6.51** |
Self-report Anxiety problems M (SD) | 4.83 (4.42) | 5.14 (4.25) | Z = − 0.01 | 3.62 (3.54) | 5.74 (4.59) | Z = − 6.81** |
Self-report Rule Breaking behavior, score/problems M (SD) | 5.14 (3.19) | 4.11 (2.87) | Z = − 4.88** | 4.38 (2.74) | 3.87 (2.96) | Z = − 3.01* |
Self-report Aggressive behavior M (SD) | 5.86 (4.24) | 5.15 (3.93) | Z = − 2.37* | 5.12 (3.72) | 5.18 (4.12) | Z = − 0.16 |
Parent-report Rule Breaking behavior, score/problems M (SD) | 2.73 (3.05) | 2.04 (2.32) | Z = − 3.02* | 2.22 (2.44) | 1.87 (2.19) | Z = − 1.85 |
Parent-report Aggressive behavior M (SD) | 4.77 (4.84) | 4.22 (4.30) | Z = − 1.04 | 4.01 (3.86) | 4.42 (4.67) | Z = − 0.51 |
Non-verbal IQ-score ! M (SD) | 93.95 (12.73) | 99.12 (13.57) | Z = − 5.29** | 99.61 (13.85) | 98.68 (13.34) | Z = − 0.80 |