Table 3.

Methodological quality of studies of effect of acute THC challenge on salience processing

Study	Defined Study Population	Random-isation	Blinding	Inter-vention	Adequate control	Outcome measurement	Statistical analysis	Drop-out rate specified	Excluded/adjust-ment for tobacco con-founding	Funding or Sponsor-ship
Metrik et al. (2015)	✓ Healthy regular cannabis users	✕ Not specified	✓ Double	✓ Marijuana cigarettes	✓ Placebo cigarette	✓ Emotional processing task	✓ GEE analyses	✓ 26/115 (22.6%)	✕ Tobacco in cigarettes, tobacco smokers allowed smoke after CO test	✓ Declared
Ballard et al. (2012)	✓ Healthy occasional cannabis users	✕ Not specified	✓ Double	✓ THC capsule	✓ Placebo	✓ Emotional processing task	✓ Two-way repeated measures ANOVA	✕ Not specified	✕ Normal amounts of caffeine and nicotine consumed	✓ Declared
Bhattacharyya et al. (2012)	✓ Healthy volunteers, minimal cannabis use	✕ Not specified	✓ Double	✓ THC capsule	✓ Placebo	✓ -Visual oddball task performance - Regional brain activity	✓ Pairwise comp-arisons; repeated measures ANOVA	✕ Not specified	✕ Not specified	✓ Declared
Phan et al. (2008)	✓ Healthy occasional cannabis users	✓	✓ Double	✓ THC capsule	✓ Placebo	✓ - Emotional processing task - Regional brain activity	✓ ANOVA	✓ 2/16 (12.5)	✕ Not specified, asked to abstain from all drugs 24h before, and 23h after session	✓ Declared
Hooker et al. (1987)	✓ Healthy volunteers, occasional cannabis use	✕ Not specified	✓ Double	✓ THC cigarette	✓ Placebo	✓ Stroop, memory and attention task performance	✓ Repeated measures ANOVA	✕ Not specified	✕ Not specified	✕ Not specified

Occasional use refers to exposure more the 10 x in their lives, but not using daily. Regular use refers to use at least 2 days a week in the past month, at least weekly the previous 6 months. Minimal use <15 times/lifetime. THC – tetrahydrocannabinol; ANOVA – Analysis of variance