Table 2.
Childhood characteristics of those with neurodevelopmental (ND) difficulties compared to those without
| ND difficulties (n ≤ 1,697) | No ND difficulties (n ≤ 3,177) | Test statistic | |
|---|---|---|---|
| Gendera (% male (n)) | 63.1% (1,071) | 47.3% (1,503) | χ2 = 110.8, p < .001 |
| Social class based on mother's occupationb (% I/II (n)) | 29.2% (407) | 40.2% (1,153) | χ2 = 49.4, p < .001 |
| Oppositional defiant disorderc (% (n)) | 16.4% (228) | 0.6% (20) | χ2 = 468.8, p < .001 |
| Any anxiety disorderd (% (n)) | 4.8% (68) | 1.1% (36) | χ2 = 60.3, p < .001 |
| Major depressive disordere (% (n)) | 2.2% (30) | 0.4% (11) | χ2 = 35.7, p < .001 |
| Irritable scoref (mean) | 1.25 | 0.33 | t(4,510) = −24.5, p < .001 |
| Special educational needsg (% (n)) | 29.9% (403) | 3.2% (101) | χ2 = 672.5, p < .001 |
Numbers for analysis: a n = 4,874, b n = 4,261, c n = 4,566, d n = 4,582, e n = 4,506, f n = 4,512, g n = 4,488.
Social class based on occupation split into I/II or II/IV/V. DSM‐IV diagnoses of oppositional defiant disorder, any anxiety disorder and major depressive disorder derived using parent‐rated Development and Well‐Being Assessment (DAWBA) at the age of 7. Irritable score calculated using 3 items from parent‐rated DAWBA at the age of 7 (temper outbursts, touchy/easily annoyed, angry/resentful)—possible score = 0–6.