Table 4.

Neurocognitive Scores Stratified by Dopamine D₂ Occupancy

D2 Occupancy Level	D2 Occupancy Range (%)	z Score (Mean ± SD)
		Verbal Memory	Vigilance	Processing Speed	Reasoning	Working Memory	Summary Score
Low (n = 102)	15.5–62.7	0.084 ± 1.077	0.174 ± 0.964	0.159 ± 0.958	0.311 ± 0.866a	0.293 ± 0.787	0.275 ± 0.920
Slightly low (n = 102)	62.7–71.8	0.188 ± 1.015	0.306 ± 0.992b	0.223 ± 0.889	0.259 ± 0.899	0.229 ± 0.880	0.323 ± 0.937
Slightly high (n = 103)	71.9–77.2	0.180 ± 0.865	0.385 ± 0.951c	0.167 ± 0.913	0.285 ± 0.853	0.309 ± 0.736	0.354 ± 0.839d
High (n = 103)	77.2–85.8	0.025 ± 0.990	−0.110 ± 0.934	−0.085 ± 0.903	−0.013 ± 0.949	0.095 ± 1.017	−0.008 ± 0.951

Note: Significant differences were found in vigilance score, reasoning score, and summary score (F _{3, 406} = 5.21, P = .002; F _{3, 406} = 2.90, P = .04; F _{3, 406} = 3.36, P = .02, respectively) by the one-way ANOVA.

^a P =.049 by the Turkey-Kramer HSD (honestly significant difference), vs high D₂ group.

^b P = .012 by the Turkey-Kramer HSD, vs high D₂ group.

^c P = .002 by the Turkey-Kramer HSD, vs high D₂ group.

^d P = .025 by the Turkey-Kramer HSD, vs high D₂ group.