Table 1.
Demographic and clinical characteristics of ADHD children with different DRD4 48-bp VNTR polymorphism genotypes.
| Characteristic | DRD4-4R/4R (n = 30) | DRD4-2R (n = 19) | Statistics |
|---|---|---|---|
| Age (years) | 10.50 ± 1.87 | 9.50 ± 1.76 | t = 1.846, P = 0.071 |
| Male | 27 (90%) | 16 (84%) | χ2 = 0.024, P = 0.877 |
| Female | 3 (10%) | 3 (16%) | χ2 = 0.024, P = 0.877 |
| Right-handed | 30 (100%) | 19 (100%) | |
| IQ | 116.50 ± 18.89 | 115.60 ± 13.74 | t = 0.173, P = 0.863 |
| ADHD subtype | |||
| Inattentive | 14 (47%) | 6 (31%) | χ2 = 1.097, P = 0.578 |
| Hyperactive-Impulsive | 5 (16%) | 4 (21%) | χ2 = 1.097, P = 0.578 |
| Combined | 11 (37%) | 9 (47%) | χ2 = 1.097, P = 0.578 |
| Conners’ Parent Rating Scale | |||
| Mean Impulsivity-Hyperactivity | 1.59 ± 0.67 | 1.70 ± 0.70 | t = − 0.531, P = 0.598 |
| Mean Conners Index of Hyperactivity | 1.56 ± 0.56 | 1.61 ± 0.62 | t = − 0.282, P = 0.779 |
| Stroop Color Word Test | |||
| Stroop reaction time (s) | 2.77 ± 1.12 | 2.83 ± 1.09 | t = − 0.185, P = 0.854 |