Table 2.

	Author		Journal	Study aim	POPULATION C / Usertype		SPECIFICATION OF STUDIE DESIGN Parallel, crossover, placebo / abstinence time		Tests/ measurements of Impulsivity and Motor Control
acute effects	Borgwardt et al. 2008		Biological Psychiatry	fMRI, acute effects of THC on motor inhibition in healthy volunteers	-	15 healthy male volunteers (<15 times use in lifetime)	double-blind, pseudo-random., placebo-contr. rep. meas. within-sub.	1 month	Go/No-Go-task
	Weinstein et al. 2007		Psychopharmacology	18FDG-PET, acute 17mg THC on motor control in regular marijuana users	-	12 regular users (1 joint per day at least 5 years)	Double-blind, placebo-controlled, cross-over	Requested only, the night before	Psycho-motor(virtual maze) task; WCST, IGT, estimates of time and distance of a car
	O'Leary et al. 2003		NeuroReport	H215O-PET, acute effects of THC, perfusion and internal timing in heavy compared to moderate use	-	12 heavy(daily 1.8 joints since 5.4y) / 12 moderate (once a week since 3.9y)	Double-blind placebo-controlled counterbalanced design	-	Self-paced counting task Self-paced finger-tapping task
non-acute effects	functional	Gruber et al. 2012	Neuroscience Letters	fMRI, inhibiting impulsive behaviors in early (<16y) vs. late onset MJs	16 <15x	23heavy (2500+joint)MJ (n=9 <16y/ n=15 +16y) / 16 non-smoking HC	Cross-sectional	12h	MSIT
		Hestor et al. 2009	Neuropsychopharmacology	fMRI, inhibitory control and error awareness in chronic MJ	16	16 chronic users (500+ joints, 5-7x/week for 2y)	Cross-sectional	-	Go/No-Go-task; EAT
		Tapert et al.  2007	Psychopharmacology	fMRI, go/no-go task in adolescent marijuana users after 28 days of abstinence.	17	16 recreational (+60 lifetime)	Cross-sectional	28 days	Go/No-Go-task
		Bolla et al. 2005	NeuroImage	H215O-PET, 25-day abstinent MJ users dose-related alterations in the Iowa Gambling (IGT)	11	11 heavy chronic users (4/w for 2y) (8-35j/w vs. 53-84j/w)	Cross-sectional	28 days	IGT, resting state, sensorimotor Control-task
		Gruber et al.  2005	Cognitive brain research	fMRI, DTI, frontal dysfunctions & structural changes in heavy cannabis use in modified Stroop task	9	9 chronic users (4000+ joints)	Cross-sectional	Urine+/- for THC, but not others	STROOP-task
		Eldreth et al. 2004	NeuroImage	PET 15O, modified Stroop task, 25-day abstinent, heavy MJ users, executive cognitive functioning	11	11 chronic users (4/w for 2y)	Cross-sectional	23d MJ 3d Controls Urine sample time range	Rest-R (eyes fixated on a target); Active Task-A (Conflict condition STROOP);Control Task-C (sensorimotor No Conflict condition)
	structural	Gruber et al.  2011	Experimental and Clinical Psychopharmacollogy	DTI, impulsivity measures in chronic heavy MJ smokers, white matter microstructure	15	15 chronic users	Cross-sectional	-	BIS-11
		Siveri et al.  2011	Psychiatry Research	MRSI in MJ-dependence	11	15 chronic users MJ 1.use=15.7±2.2y for 5.5±2.6y; 5.6±1.7/week	Cross-sectional	Non Urine+/-	BIS-11, +3 affect/mood scales
		Churchwell et al.  2010	Frontiers in Psychology	MRI, functional integrity of moPFC, reward perception, substance abuse, and dependence.	18	18 recreational users	Cross-sectional	Continued use until study visit	BIS-11
		Hermann et al. 2007	Biological Psychiatry	1H-MRS, Cannabinoids neurotoxic and neuroprotective properties inconsistent alterations neuropsychological deficits, neuropsychological testing	13	14 chronic recreational users	Cross-sectional	Non Urine+/-	WCST, TMT, D2
		Gruber et al. 2005	Cognitive brain research	DTI, heavy cannabis smokers performing a modification of the classic Stroop task.	9	9 chronic users (4000+ joints)	Cross-sectional	Urine+/- for THC, but not others	STROOP

BIS-11: Barratt Impulsivity Scale-11; C: Controls; DTI: Diffusion tensor imaging technique; EAT: Error Awareness Task; IGT: Iowa Gambling task; MJ: Marijuana user; MRSI: proton magnetic resonance spectroscopic imaging; MSIT: Multi-Source Interference Task; PET: positron emission tomographic imaging; STROOP: Stroop Colour Word Test; WCST: Wisconsin card sorting test, (Heaton, 1999);