Participant demographic and clinical characteristics
| Characteristic | All participants n = 92 | Methylphenidate response n = 67 | ||||
|---|---|---|---|---|---|---|
| ADHD n = 67 | Control n = 25 | p value | Responders n = 44 | Nonresponders n = 23 | p value | |
| Age, yr | 9.76 ± 2.51 | 10.00 ± 2.50 | 0.69 | 9.45 ± 2.37 | 10.35 ± 2.72 | 0.17 |
| Female, n (%) | 13 (19.4) | 14 (56) | 0.002 | 9 (20.5) | 4 (17.4) | 0.76 |
| IQ | 107.79 ± 13.22 | 116.92 ± 10.80 | 0.003 | 107.52 ± 12.33 | 108.30 ± 15.07 | 0.82 |
| ADHD rating scale (pretreatment) | ||||||
| Inattentive | 15.03 ± 5.61 | 3.04 ± 3.97 | < 0.001 | 15.68 ± 5.94 | 13.78 ± 4.80 | 0.19 |
| Hyperactive–impulsive | 10.87 ± 5.42 | 1.36 ± 1.63 | < 0.001 | 11.20 ± 5.69 | 10.22 ± 4.93 | 0.48 |
| Continuous Performance Test (pretreatment) | ||||||
| Omission error | 65.21 ± 20.79 | 50.80 ± 6.89 | 0.001 | 64.57 ± 20.25 | 66.43 ± 22.21 | 0.73 |
| Commission error | 63.85 ± 17.32 | 57.56 ± 14.64 | 0.11 | 64.00 ± 17.52 | 63.57 ± 17.32 | 0.92 |
| Final methylphenidate dose, mg | 32.45 ± 11.97 | — | — | 32.61 ± 11.24 | 32.13 ± 13.54 | 0.88 |
| Final methylphenidate dose, mg/kg | 0.92 ± 0.25 | — | — | 0.98 ± 0.25 | 0.81 ± 0.22 | 0.01 |
ADHD = attention-deficit/hyperactivity disorder.
Values are mean ± standard deviation unless otherwise specified.