Table 1.
Descriptive statistics for population-based sibling study
| Characteristic | Without ADHD (N = 2,003,112) |
With ADHD (N = 79,006) |
|---|---|---|
| Person-years | 21,436,933 | 912,035 |
| Sex | ||
| Females | 985,912 (49.22%) | 25,505 (32.28%) |
| Males | 1,017,200 (50.78%) | 53,501 (67.72%) |
| Parental education | ||
| High | 464,991 (23.68%) | 10,555 (13.74%) |
| Low | 290,567 (14.79%) | 16,632 (21.66%) |
| Medium | 1,208,479 (61.53%) | 49,605 (64.60%) |
| No information | 39,075 | 2,214 |
| Disposable income (SEK) parental | 2,119 (1,669, 2,634) | 1,924 (1,441, 2,396) |
| No information | 39,075 | 2,214 |
| Traumatic events | ||
| Sexual abuse | 4,508 (0.23%) | 889 (1.13%) |
| Fire or explosion | 20,409 (1.02%) | 1,336 (1.69%) |
| Transportation accident | 153,933 (7.68%) | 10,271 (13.00%) |
| Exposure to toxic substance | 181,797 (9.08%) | 15,082 (19.09%) |
| Traumatic brain injury | 107,552 (5.37%) | 7,260 (9.19%) |
| Physical assault | 13,043 (0.65%) | 1,734 (2.19%) |
| Assault with a weapon | 2,403 (0.12%) | 391 (0.49%) |
| Death of a family member < 18 | 45,758 (2.28%) | 3,312 (4.19%) |
| Risk-taking behaviors | ||
| Criminal conviction | 114,875 (5.73%) | 15,053 (19.05%) |
| Pregnancy before age 18 | 2,201 (0.11%) | 332 (0.42%) |
| Divorce before age 20 | 201 (0.01%) | 22 (0.03%) |
| Marriage before age 18 | 612 (0.03%) | 27 (0.03%) |
| PTSD | ||
| Without PTSD | 1,999,875 (99.84%) | 77,819 (98.50%) |
| With PTSD | 3,237 (0.16%) | 1,187 (1.50%) |