Table 3.

Measures of DA D2/D3 receptor availability (Bmax/Kd) in ADHD participants and controls in the NAcc and midbrain regions and correlations with the scores on the Achievement Scale (surrogate trait measure of motivation) for analysis done with all subjects (ALL) and for analysis done with only ADHD participants (ADHD). The correlations with controls were not significant. Measures correspond to mean and standard deviation.

D2/D3 receptors	Controls (n=41)	ADHD (n=45)	Correlations with Achievement Scale
NAcc region*	2.65 ±0.27	2.53 ±0.22	ALL r=0.27, p<0.01; ADHD: r=0.39, p<0.008
Midbrain**	0.28 ±0.12	0.20 ±0.17	ALL r=0.36, p<0.0007; ADHD r=0.41, p<0.005
DAT
NAcc region*	0.60 ±0.14	0.55 ±0.10	ALL r=0.20, p<0.07; ADHD r=0.35, p<0.02
Midbrain	0.14 ±0.09	0.10 ±0.09	ALL r=0.18, NS; ADHD R=0.17, NS

Comparisons between groups correspond to independent samples t tests (two tail)

^*p < 0.05;

^**p < 0.01