Table 1.
Demographic and clinical characteristics of the participants
| ADHD (N = 58) | Val/Val (N = 29) | Met/Val + Met/Met (N = 29) | P | ||||
|---|---|---|---|---|---|---|---|
| Age (years), mean (SD) | 8.69 | (2.13) | 8.54 | (1.66) | 8.21 | (2.57) | 0.72 |
| Gender (female), N (%) | 13 | (22.4) | 5 | (17.2) | 8 | (27.6) | 0.34 |
| Body weight (kg), mean (SD) | 32.86 | (11.65) | 34.03 | (10.93) | 31.69 | (12.42) | 0.44 |
| Intelligence quotient, mean (SD) | 105.00 | (12.41) | 106.97 | (11.21) | 103.03 | (13.40) | 0.23 |
| Handedness (right), N (%) | 51 | (87.9) | 25 | (86.2) | 26 | (89.7) | 0.99 |
| Continuous performance test, mean (SD) | |||||||
| Omission errors | 66.84 | (20.42) | 64.55 | (20.90) | 71.86 | (20.70) | 0.18 |
| Response time variability | 66.45 | (17.17) | 64.14 | (17.56) | 66.83 | (17.99) | 0.56 |
| Social variables | |||||||
| Paternal education (years), mean (SD) | 14.91 | (1.90) | 14.89 | (2.02) | 14.92 | (1.80) | 0.95 |
| Maternal education (years), mean (SD) | 14.82 | (1.84) | 14.62 | (1.94) | 15.04 | (1.74) | 0.41 |
| Familial socioeconomic status, N (%) | 0.17 | ||||||
| High (very or moderately) | 14 | (25.9) | 6 | (21.5) | 8 | (30.8) | |
| Middle class | 32 | (59.3) | 20 | (71.4) | 12 | (46.2) | |
| Low (very or moderately) | 8 | (14.8) | 2 | (7.1) | 6 | (23.0) | |
| Obstetric variables, mean (SD) | |||||||
| Maternal age at pregnancy (years) | 29.84 | (3.59) | 29.88 | (3.50) | 29.80 | (3.76) | 0.93 |
| Child's birth weight (kg) | 3.26 | (0.47) | 3.32 | (0.47) | 3.20 | (0.47) | 0.38 |
| ADHD types, N (%) | 0.44 | ||||||
| Combined | 33 | (56.9) | 18 | (62.1) | 15 | (51.7) | |
| Inattentive | 19 | (32.8) | 10 | (34.5) | 9 | (31.0) | |
| Hyperactive‐impulsive | 1 | (1.7) | 0 | (0.0) | 1 | (3.4) | |
| Not otherwise specified | 5 | (8.6) | 1 | (3.4) | 4 | (13.8) | |
| Oppositional defiant disorder, N (%) | 11 | (19.0) | 3 | (10.3) | 8 | (27.6) | 0.09 |
| Anxiety disorder, N (%) | 2 | (3.4) | 0 | (0.0) | 2 | (6.9) | 0.49 |
| Final MPH dose (mg), mean (SD) | 30.44 | (11.49) | 31.10 | (11.37) | 29.61 | (11.85) | 0.64 |
| Final MPH dose per weight (mg/kg), mean (SD) | 0.94 | (0.26) | 0.92 | (0.28) | 0.97 | (0.24) | 0.55 |
Different number of total respondents for paternal education (N = 54), maternal education (N = 51), familial socioeconomic status (N = 54), maternal age at pregnancy (N = 52), child's birth weight (N = 51) and final MPH dose (N = 52). ADHD, attention‐deficit/hyperactivity disorder; MPH, methylphenidate; SD, standard deviation.