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. Author manuscript; available in PMC: 2016 Oct 1.
Published in final edited form as: JAMA Psychiatry. 2015 Oct 1;72(10):994–1001. doi: 10.1001/jamapsychiatry.2015.1054

Table 2.

Regression Results for the Association Between Cannabis-Related Measures and Brain Volumesa

Cannabis Exposed vs Unexposed
(n = 483)
 Lifetime Amount of Use Among Exposed Individuals
(n = 262)
Regression Coefficients
 Regression Coefficients
Volume Unstandardized (b) Standardized (β) P Value Bootstrapped
95%CI		 Unstandardized (b) Standardized (β) P Value Bootstrapped
95%CI
Whole brain −6684.22 −0.06 .38 −21717.0 to
8106.0		 −6568.31 −0.06 .06 −13893.0 to
501.0
Amygdala
 Left −34.68b,c −0.18b,c .007b,c −60.65 to
−11.01b,c 		−4.72 −0.03 .43 −14.97 to
5.20
 Right −20.64 −0.10 .13 −45.94 to
6.65		 −10.50 −0.05 .09 −23.11 to
0.75
Hippocampus
 Left −29.51 −0.06 .30 −91.44 to
33.27		 −31.83c −0.07c .05c −61.96 to
−3.03c
 Right 14.90 0.03 .61 −43.83 to
73.13		 −15.58 −0.04 .26 −43.46 to
11.25
Ventral striatum
 Left −0.59 −0.01 .94 −15.12 to
13.15		 0.26 0.00 .94 −6.09 to
7.1
 Right −20.87b,c −0.22b,c .005b,c −35.69 to
−6.44b,c 		−2.83 −0.03 .43 −10.01 to
4.03
Orbitofrontal
cortex
 Left −88.72 −0.06 .24 −232.34 to
50.1		 −26.00 −0.02 .48 −87.24 to
42.66
 Right −21.51 −0.02 .76 −156.19 to
112.22		 −39.73 −0.03 .24 −106.98 to
23.96
a

Unstandardized (b) and standardized (β) regression coefficients and their associated P values are presented for the effects of cannabis exposure and lifetime quantity of use (among cannabis-exposed individuals) from separate linear regression models predicting whole-brain or regional volume. Bootstrapped confidence intervals are also presented for each estimate (5000 bootstrap iterations; bias-corrected accelerated percentile intervals). Regressions controlled for sex, age (years), race/ethnicity (white vs not; African American vs not), zygosity (monozygotic vs not; dizygotic vs not), total household income, picture vocabulary, and whole-brain volume (when predicting regional volumes). Negative regression coefficients indicate smaller volumes for exposed vs unexposed individuals or greater lifetime quantity of use.

b

Effects passing false-discovery rate (q < 0.05) correction.

c

Effects significant at P < .05.