Table 2.
Effects of MPH on Cognition, Academic Motivation, and Perceived Academic Competence.
| ADHD |
TD | PLA vs. MPH | PLA vs. TD | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| PLA |
MPH |
|||||||||
| M | SD | M | SD | M | SD | t | d | T | d | |
| Cognition | ||||||||||
| Verbal working memory | ||||||||||
| Number correct × Achieved level (DS) | 13.98 | 9.81 | 16.22 | 12.89 | 15.58 | 9.02 | 486(W) | 1779.5(U) | ||
| Visuospatial working memory | ||||||||||
| Number correct × Achieved level (Grid) | 54.95 | 33.86 | 57.66 | 37.27 | 76.30 | 35.21 | 0.47 | 3.52** | 0.63 | |
| RT speed | ||||||||||
| IE (Flanker, neutral condition) | 628.86 | 133.41 | 625.51 | 135.18 | 610.92 | 136.76 | 4284(W) | −0.75 | ||
| Lapses of attention | ||||||||||
| Tau (Flanker, neutral condition) | 150.33 | 74.72 | 135.57 | 88.06 | 100.52 | 75.14 | −1.77† | 0.32 | −3.74** | 0.67 |
| Interference control | ||||||||||
| IE (Flanker, incongruent–congruent) | 100.18 | 63.94 | 104.77 | 135.11 | 85.54 | 63.72 | 0.62a | 2339(U) | ||
| Motivation and competence | ||||||||||
| Intrinsic motivation General (CAIMI) | 60.05 | 8.47 | 60.13 | 9.91 | 62.48 | 8.24 | 0.17 | 1.65 | ||
| Intrinsic motivation Math (CAIMI) | 76.34 | 20.70 | 77.37 | 20.39 | 84.39 | 13.87 | 0.90 | 2.61* | 0.46 | |
| Intrinsic motivation Reading (CAIMI) | 80.08 | 19.99 | 81.33 | 19.85 | 83.75 | 17.21 | 1.04 | 1.12 | ||
| Reward responsivity (SPSRQ-C) | 22.32 | 4.99 | 21.77 | 5.22 | 19.26 | 4.24 | −0.98 | −3.73** | 0.67 | |
| Sensitivity to punishment (SPSRQ-C) | 38.23 | 9.32 | 37.69 | 10.12 | 35.35 | 7.72 | −0.94 | −1.90‡ | 0.34 | |
| Self-perceived competence (SPPC-S) | 15.05 | 3.17 | 15.41 | 3032 | 17.03 | 2.52 | 1.30 | 3.96** | 0.70 | |
| Parent-rated self-perceived competence (SPPC-S) | 14.40 | 2.82 | 15.44 | 3.37 | 17.97 | 2.78 | 2.93** | 0.53 | 7.18** | 1.28 |
| Teacher-rated self-perceived competence (SPPC-S) | 14.19 | 2.99 | 14.32 | 3.25 | 17.38 | 3.20 | 0.87 | 5.80** | 1.03 | |
Note. MPH = methylphenidate; TD = typically developing controls; PLA = placebo; W = Wilcoxon signed-rank test statistic; U = Mann-Whitney U test statistic; DS = Digit Span backward; RT = reaction time; IE = inverse efficiency calculated as mean RT/proportion correct; CAIMI = Children’s Academic Intrinsic Motivation Inventory; SPSRQ-C = Sensitivity to Punishment and Sensitivity to Reward Questionnaire for Children; SPPC-S = Self Perception Profile for Children–School Scale; Accuracy = Items correct / Items completed × 100%; Productivity = Items completed / Items available × 100%.
Treatment (MPH versus placebo) by condition (congruent versus incongruent) interaction.
p = .08. ‡p = .06. *p < .05. **p < .01.