Table 3. [¹¹C]-(+)-Dihydrotetrabenazine binding (BP _ND) in Healthy Controls and Users of Cocaine and MAa.

	Control subjects (n=22)	Cocaine users (n=9)	MA users	p-Valueb (Bonferroni-corrected)
				MA vs controls	MA vs cocaine
First scan
LST	1.76±0.29	1.69±0.26	2.19±0.63 (n=28, all)	0.010	0.027
			1.97±0.65 (n=17, ‘abstainer')	0.472	0.384
			2.46±0.55 (n=7, ‘relapser')	<0.0001	<0.0001
AST	2.38±0.34	2.56±0.35	3.13±0.71 (n=28, all)	<0.0001	0.026
			2.90±0.75 (n=17, ‘abstainer')	0.013	0.379
			3.44±0.55 (n=7, ‘relapser')	<0.0001	<0.0001
SMST	2.93±0.40	3.16±0.47	3.68±0.82 (n=28, all)	<0.0001	0.126
			3.43±0.83 (n=17, ‘abstainer')	0.038	0.848
			3.97±0.81 (n=7, ‘relapser')	<0.0001	0.010
Full striatum	2.41±0.34	2.55±0.30	3.09±0.71 (n=28, all)	<0.0001	0.040
			2.85±0.74 (n=17, ‘abstainer')	0.031	0.493
			3.38±0.59 (n=7, ‘relapser')	<0.0001	<0.0001
	(n=9)	(n=8)	(n=17, ‘abstainers')
Second scan
LST	1.72±0.30	1.77±0.21	1.74±0.41	1.0	1.0
AST	2.48±0.36	2.53±0.42	2.57±0.38	1.0	1.0
SMST	3.02±0.41	3.22±0.50	3.08±0.48	1.0	1.0
Full striatum	2.46±0.34	2.58±0.35	2.54±0.39	1.0	1.0

Abbreviations: AST, associative striatum; LST, limbic striatum; MA, methamphetamine; SMST, sensorimotor striatum.

Data in mean±SD. The first scan was performed during very early abstinence at 1–7 (mean 2.6) days after last drug use, whereas the second scan was performed ~1 week (5–9 days) after the first scan, that is, 7–15 (mean 9.8) days after the last drug use. ‘Abstainers' are users who were able to maintain continued abstinence between the two scans; ‘relapsers' are those who were unable to remain abstinent for the length of the study and thus did not receive a second scan. There were also four MA users who did not receive or complete a second scan for other reasons (eg, drop out or excessive head movement).

^aDuring early (first scan) and later (second scan) abstinence.

^bRepeated-measures ANOVA with a within-subject factor (ROI) and a between-subject factor (group) was used, followed by least significant difference t-tests, Bonferroni corrected for planned comparisons.

Bold values indicate significance at p<0.05.