Table 3. Voxel composition by group.
| Healthy control |
ADHD |
P1-value | P2-value | |||
|---|---|---|---|---|---|---|
| Total | Medicated | Not medicated | ||||
| Basal ganglia | ||||||
| Grey | 0.70 (0.12) | 0.72 (0.083) | 0.71 (0.06) | 0.73 (0.098) | 0.406 | 0.542 |
| White | 0.37 (0.12) | 0.33 (0.08) | 0.34 (0.06) | 0.33 (0.09) | 0.221 | 0.690 |
| CSF | 0.008 (0.01) | 0.007 (0.01) | 0.007 (0.01) | 0.008 (0.01) | 0.886 | 0.906 |
| Dorsolateral prefrontal cortex | ||||||
| Grey | 0.28 (0.10) | 0.25 (0.06) | 0.24 (0.04) | 0.26 (0.07) | 0.156 | 0.453 |
| White | 0.75 (0.10) | 0.78 (0.07) | 0.78 (0.05) | 0.77 (0.08) | 0.297 | 0.660 |
| CSF | 0.017 (0.01) | 0.014 (0.01) | 0.014 (0.01) | 0.014 (0.01) | 0.340 | 0.959 |
| Parietal cortex | ||||||
| Grey | 0.45 (0.05) | 0.47 (0.07) | 0.48 (0.08) | 0.47 (0.06) | 0.184 | 0.690 |
| White | 0.51 (0.08) | 0.5 (0.08) | 0.48 (0.09) | 0.51 (0.06) | 0.591 | 0.373 |
| CSF | 0.09 (0.04) | 0.069 (0.03) | 0.074 (0.03) | 0.066 (0.03) | 0.022* | 0.388 |
Abbreviations: ADHD, attention-deficit hyperactivity disorder; CSF, cerebrospinal fluid. Data are given as mean (s.d.). Values represent estimated mean proportion of voxel (range 0–1). P1, controls vs ADHD (both stimulant naive and medicated) t-test; P2, ADHD naive vs ADHD medicated. These showed no significant differences except in parietal cortex % CSF (P<0.05) that was significantly higher in the healthy controls compared with the ADHD groups, with no differences between the medicated and medication naive ADHD groups. * indicates that the comparison was significant at P<0.05.