Table 1.
Demographic and clinical characteristics of the sample population
| Characteristics | Total sample (N = 1887) | With ADHD (n = 1276) | Without ADHD (n = 611) | p* |
|---|---|---|---|---|
| Age M (SD); median | 9.3 (2.5); 9 | 9.1 (2.4); 9 | 9.7 (2.5); 9 | <0.0001 |
| 5–11, n (%) | 1506 (80) | 1038 (81) | 468 (77) | 0.0161 |
| 12–17, n (%) | 381 (20) | 238 (19) | 143 (23) | |
| Male: female | 1597:290 | 1099:177 | 498:113 | 0.0092 |
| Only child, n (%) | 453 (24) | 328 (26) | 125 (20) | 0.0116 |
| Born abroad, n (%) | 99 (5) | 76 (6) | 23 (4) | 0.0453 |
| Adopted, n (%) | 63 (3) | 54 (4) | 9 (1) | 0.0018 |
| School variables, n (%) | ||||
| Grade | ||||
| Primary | 1417 (75) | 980 (77) | 437 (72) | 0.0139 |
| Middle | 465 (25) | 293 (23) | 172 (28) | |
| Repeaters | 99 (5) | 61 (5) | 38 (6) | ns |
| Support teacher | 142 (8) | 123 (10) | 19 (3) | <0.0001 |
| Parent/family variables, n (%) | ||||
| High school graduate | ||||
| Mother | 1070 (64) | 694 (63) | 376 (66) | ns |
| Father | 871 (53) | 562 (52) | 309 (55) | ns |
| Employed | ||||
| Mother | 1235 (72) | 840 (74) | 395 (67) | 0.0028 |
| Father | 1584 (95) | 1046 (95) | 538 (94) | ns |
| Family history of ADHD | 375 (20) | 293 (23) | 82 (13) | <0.0001 |
| Anamnestic data, n (%) | ||||
| Pregnancy | ||||
| Cesarean section | 465 (26) | 333 (28) | 132 (23) | 0.0207 |
| Preterm (<37 weeks) | 168 (9) | 120 (10) | 48 (8) | ns |
| Low weight (<2500 g) | 149 (9) | 107 (9) | 42 (7) | ns |
| Motor delay | 85 (5) | 60 (5) | 25 (4) | ns |
| Language delay | 366 (20) | 266 (22) | 100 (17) | 0.0167 |
| Psychiatric disorders, n (%) | ||||
| One or more | 1189 (63) | 843 (66) | 346 (57) | <0.0001 |
| Other chronic medical conditions, n (%) | ||||
| One or more | 163 (9) | 110 (9) | 53 (9) | ns |
* t test for continuous and χ2 for categorical variables