Table 5 Rates of screening positive for behavioral and socioemotional symptomatology within a twin pair by birth order.
Characteristics, % (numerator/denominator) | First-born twin [n = 349] | Second-born twin [n = 349] | p | Risk ratio (95% confidence interval) | Total sample [N = 349 twin pairs] |
|---|---|---|---|---|---|
ADHD | |||||
Combined | 7.80 (27/346) | 10.98 (38/346) | 0.10 | 1.41 (0.88–2.25) | 9.39 (65/692) |
Hyperactivity/impulsivity | 12.43 (43/346) | 18.79 (65/346) | 0.004 | 1.51 (1.06–2.16) | 15.61 (108/692) |
Inattention | 14.74 (51/346) | 19.65 (68/346) | 0.05 | 1.33 (0.96–1.86) | 17.20 (119/692) |
ASD | |||||
Overall | 9.58 (32/334) | 22.75 (76/334) | <0.001 | 2.38 (1.62–3.49) | 16.17 (108/668) |
Social awareness | 12.20 (41/336) | 32.74 (110/336) | <0.001 | 2.68 (1.94–3.71) | 22.47 (151/672) |
Social cognition | 8.63 (29/336) | 38.39 (129/336) | <0.001 | 4.45 (3.06–6.46) | 23.51 (158/672) |
Social communication | 8.38 (28/334) | 19.76 (66/334) | <0.001 | 2.36 (1.56–3.57) | 14.07 (94/668) |
Social motivation | 12.20 (41/336) | 13.69 (46/336) | 0.58 | 1.12 (0.76–1.66) | 12.95 (87/672) |
Restricted/repetitive behavior | 10.12 (34/336) | 19.35 (65/336) | <0.001 | 1.91 (1.30–2.81) | 14.73 (99/672) |
Anxiety | |||||
Overall | 30.95 (108/349) | 41.55 (145/349) | <0.001 | 1.34 (1.10–1.64) | 36.25 (253/698) |
Generalized anxiety | 34.96 (122/349) | 46.70 (163/349) | <0.001 | 1.34 (1.11–1.60) | 40.83 (285/698) |
Social anxiety | 27.79 (97/349) | 36.68 (128/349) | 0.002 | 1.32 (1.06–1.64) | 32.23 (225/698) |
Separation anxiety | 34.96 (122/349) | 40.40 (141/349) | 0.06 | 1.16 (0.95–1.40) | 37.68 (263/698) |
