Table 1.
Demographic and Clinical Characteristics, Genotype Frequencies, and Lead and Cotinine Levels of the Good and Poor Responders to MPH in ADHD Participants
| Good Responder (n=48) | Poor Responder (n=30) | P Value | |
|---|---|---|---|
| Age, mean (SD) years | 9.4 (2.3) | 9.8 (2.8) | 0.48 |
| Female, n (%) | 11 (22.9%) | 5 (16.7%) | 0.51 |
| IQ, mean (SD) | 108 (12) | 105 (15) | 0.41 |
| Handedness (right), n (%) | 42 (87.5%) | 28 (93.3%) | 0.34 |
| CPT, mean (SD) | |||
| Omission errors | 64.5 (20.3) | 68.3 (21.8) | 0.45 |
| Commission errors | 63.1 (17.0) | 66.4 (17.9) | 0.43 |
| Response time variability | 64.3 (17.6) | 63.7 (17.3) | 0.88 |
| SCWT | |||
| Word test | 45.1 (10.3) | 45.4 (12.3) | 0.92 |
| Color test | 44.7 (11.0) | 46.0 (10.5) | 0.60 |
| Color-Word test | 44.6 (9.5) | 49.5 (14.9) | 0.12 |
| Interference | 52.0 (11.0) | 55.8 (11.9) | 0.15 |
| ADHD-RS, mean (SD) | |||
| Inattention | 15.5 (6.2) | 14.3 (5.1) | 0.40 |
| Hyperactivity-impulsivity | 10.7 (5.7) | 11.1 (5.9) | 0.77 |
| Total | 26.2 (10.6) | 25.5 (10.5) | 0.76 |
| ADHD subtypes, n (%) | 0.64 | ||
| Combined | 25 (52.1%) | 15 (50.0%) | |
| Inattentive | 19 (39.6%) | 12 (40.0%) | |
| Hyperactive-impulsive | 0 (0.0%) | 1 (3.3%) | |
| Not otherwise specified | 4 (8.3%) | 2 (6.7%) | |
| Comorbid disorders, n (%) | |||
| Oppositional defiant disorder | 4 (8.3%) | 9 (30.0%) | 0.01 |
| Anxiety disorder | 0 (0.0%) | 1 (3.3%) | 0.20 |
| Genotype | |||
| DAT1, n (%) | 0.63 | ||
| With 10/10 | 39 (81.3%) | 23 (76.7%) | |
| Without 10/10 | 9 (18.7%) | 7 (23.3%) | |
| DRD4, n (%) | 0.64 | ||
| With 4/4 | 25 (52.1%) | 14 (46.7%) | |
| Without 4/4 | 23 (47.9%) | 16 (53.3%) | |
| ADRA2A MspI, n (%) | 0.14 | ||
| G/G | 19 (39.6%) | 17 (56.7%) | |
| G/C+C/C | 29 (60.4%) | 13 (43.3%) | |
| ADRA2A DraI, n (%) | 0.87 | ||
| C/C | 12 (25.0%) | 7 (23.3%) | |
| C/T+T/T | 36 (75.0%) | 23 (76.7%) | |
| SLC6A2 G1287A, n (%) | 0.54 | ||
| G/G | 21 (43.8%) | 11 (36.7%) | |
| G/A+A/A | 27 (56.2%) | 19 (63.3%) | |
| SLC6A2 A-3081T, n (%) | 0.68 | ||
| A/A | 17 (35.4%) | 12 (40.0%) | |
| A/T+T/T | 31 (64.6%) | 18 (60.0%) | |
| Environmental measure | |||
| Lead (µg/dL), mean (SD) | 1.5 (0.4) | 1.4 (0.4) | 0.60 |
| Cotinine (µg/g), mean (SD) | 0.6 (0.9) | 0.8 (1.8) | 0.41 |
ADHD, attention deficit hyperactivity disorder; ADHD-RS, ADHD rating scale; ADRA2A, alpha-2A adrenergic receptor gene; CPT, continuous performance test; DAT1, dopamine transporter gene; DRD4, dopamine D4 receptor gene; MPH, methylphenidate; SCWT, Stroop color word test; SLC6A2, norepinephrine transporter gene.