Table 2.

A comparison of long-term cannabis users and three comparison groups on global brain measures.

									Statistical Tests of Difference Between Long-term Cannabis Users and Comparison Groups
Brain Measure	Long-term Cannabis Users (N=80)		Comparison Group 1: Lifelong Cannabis Non-Users (N=187)		Comparison Group 2: Long-term Tobacco Users (N=68)		Comparison Group 3: Long-term Alcohol Users (N=56)		LT vs 1	LT vs 2	LT vs 3
	M	95% CI	M	95% CI	M	95% CI	M	95% CI	pFDR (punc)	pFDR (punc)	pFDR (punc)
CT	−.180	−.378, .019	.216	.074, .357	−.335	−.585, −.084	−0.197	−.466, .073	.007 (.002)	.621 (.338)	.919 (.919)
SA	−.135	−.324, .053	.027	−.095, .150	−.268	−.459, −.077	0.013	−.179, .205	.209 (.155)	.621 (.337)	.497 (.295)
TBV	−.145	−.321, .032	.073	−.056, .202	−.221	−.405, −.037	−0.009	−.191, .174	.126 (.063)	.621 (.559)	.497 (.309)
FA	−.097	−.334, .139	.079	−.052, .209	−.010	−.222, .202	−0.148	−.418, .122	.209 (.174)	.621 (.596)	.919 (.785)
WMH	.108	−.128, .344	.053	−.080, .187	.194	−.046, .433	−0.077	−.365, .212	.675 (.675)	.621 (.621)	.497 (.331)
BrainAGE	.302	.088, .516	−.207	−.337, −.077	.449	.197, .700	0.116	−.141, .373	<.001 (<.001)	.621 (.383)	.497 (.277)

Note. Means and statistical tests of group comparisons are adjusted for sex and standardized on the full sample (M=0, SD=1). Raw (non-standardized) means are given in Table S1. Group Ns are slightly lower than reported in the methods section and vary slightly due to missing data and varying QC exclusions for brain measures. Bolded values indicate an FDR-adjusted (across 6 measures) statistically significant difference compared with long-term cannabis users. LT=Long-term cannabis users, CT=cortical thickness, SA=surface area, TBV=total brain volume, FA=fractional anisotropy, WMH=white matter hyperintensities, BrainAGE=difference between age estimated from MRI data and actual chronological age, p_FDR=FDR-adjusted p-value, p_unc=uncorrected p-value.