Article Figures & Data
Figures
- Figure 1.
A, Depiction of subcortical structures evaluated for group differences between daily marijuana users and nonusers. B, Effect size of marijuana use on structure volumes from the current study and recent literature, presented as bilateral structures where available (circle/triangle) or as the entire structure (square). Average values are presented for right and left structures only. NAccFS, Freesurfer; VBM, voxel-based morphometry; L, left; R, right; NAcc, nucleus accumbens; Hpc, hippocampus; Amyg, amygdala.
Tables
- Table 1.
Subject characteristics for marijuana nonusers and daily users in adult and adolescent samples based on the past 60 and 90 d, respectively
Adults Adolescents Nonusers (N = 29) Daily users (N = 29) Significance Nonusers (N = 50) Daily users (N = 50) Significance Sex Males 16 16 36 41 Females 13 13 14 9 0.235 Age (years) 27.5 (6.8) 27.4 (7.1) 0.985 16.77 (0.95) 16.65 (1.09) 0.538 Age range (years) 18–53 19–53 14–18 14–18 Educationa 13.5 (1.8) 13.5 (1.7) 0.966 9.08 (0.98) 9.16 (1.33) 0.739 AUDIT score 11.9 (7.5) 11.9 (6.1) 0.986 7.38 (7.00) 8.10 (5.79) 0.577 AUDIT consumption score 6.7 (3.0) 7.1 (3.0) 0.691 4.06 (3.40) 4.52 (2.87) 0.466 Substance useb Alcohol (n) Drinking days 12.31 (21.47) 12.97 (18.26) 0.869 Heavy drinking days 12.2 (10.8) 16.8 (15.0) 0.185 Drinks per drinking day 4.6 (2.5) 5.7 (3.6) 0.216 5.19 (5.46) 5.42 (5.26) 0.831 Cigarettes (n) Smoking days 35.2 (28.8) 46.1 (25.2) 0.127 Cigarettes per smoking day 7.7 (8.3) 10.9 (8.2) 0.371 3.09 (4.66) 3.60 (3.70) 0.546 Marijuana (n) Smoking days 0b 60 <0.001 0b 90 <0.001 Ethnicity (n) Caucasian 13 14 10 5 Latino 6 5 30 34 Native American 3 3 1 3 African American 4 3 Asian/Pacific Islander 1 1 Mixed 4 1 3 4 Unknown 3 6 1 Depressionc 9.06 (7.79) 9.00 (6.20) 0.983 2.78 (2.81) 3.58 (3.53) 0.213 Anxietyd 8.17 (11.14) 12.63 (10.35) 0.158 IMPSS IMP 3.32 (2.47) 2.85 (2.03) 0.445 3.84 (2.22) 4.08 (2.10) 0.579 SS 7.36 (2.70) 6.67 (2.71) 0.444 7.82 (2.44) 7.56 (2.38) 0.591 Data are mean (SD), unless otherwise indicated. IMP, Impulsivity subscale; SS, sensation-seeking subscale.
↵aHighest grade completed for adults and current grade at study screening for adolescents.
↵bTimeLine Follow Back for past 60 d for adults and variables adapted from White and Labouvie (1989) for the past 90 d for adolescents.
↵cBeck Depression Inventory for adults and Children's Depression Inventory for adolescents.
↵dBeck Anxiety Inventory for adults; no measure available for adolescents.
- Table 2.
Statistics for GLMs for VBM and FreeSurfer analyses evaluating effect of marijuana between non-users and daily users
Analysis method Structure Nonusers Daily users Variance accounted for by ICV Effect size (partial η2) Variance accounted for by group Effect size (partial η2) Estimated marginal mean SE Estimated marginal mean SE F p F p VBM Adults Intracranial volume 1,922,899.00 31,018.92 1,913,330.59 31,018.92 0.048 0.828 0.001 Total brain 1,513,201.81 4119.80 1,515,438.64 4119.80 1971.974 0.000 0.973 0.147 0.703 0.003 Total gray matter 827,994.23 4163.58 829,365.60 4163.58 484.884 0.000 0.898 0.054 0.817 0.001 Total white matter 685,207.58 3898.48 686,073.04 3898.48 548.049 0.000 0.909 0.025 0.876 0.000 R accumbens 311.84 9.04 304.24 9.04 3.296 0.075 0.057 0.353 0.555 0.006 R amygdala 1453.71 30.34 1463.16 30.34 0.786 0.379 0.014 0.048 0.827 0.001 R hippocampus 3002.16 38.79 3073.21 38.79 4.396 0.041 0.074 1.677 0.201 0.030 L accumbens 311.72 9.92 320.46 9.92 4.335 0.042 0.073 0.387 0.536 0.007 L amygdala 1171.16 26.32 1159.46 26.32 0.881 0.352 0.016 0.099 0.755 0.002 L hippocampus 3065.53 43.39 3120.25 43.39 2.682 0.107 0.046 0.795 0.377 0.014 Cerebellum 7835.77 152.16 7834.36 152.16 5.694 0.020 0.094 0.000 0.995 0.000 Adolescents Intracranial volume 1,920,158.44 24,590.65 1,954,935.94 24,590.65 1.000 0.320 0.010 Total brain 1,545,844.43 3136.89 1,551,499.77 3136.89 3895.177 <0.001 0.976 1.617 0.207 0.016 Total gray matter 866,299.03 2737.60 869,082.33 2737.60 1386.205 <0.001 0.935 0.514 0.475 0.005 Total white matter 679,545.40 2345.95 682,417.44 2345.95 1600.461 <0.001 0.943 0.746 0.390 0.008 R accumbens 297.45 6.42 300.14 6.42 1.282 0.260 0.013 0.087 0.769 0.001 R amygdala 1408.51 23.32 1404.80 23.32 0.274 0.602 0.003 0.013 0.911 0.000 R hippocampus 3055.38 30.73 3018.74 30.73 3.750 0.056 0.037 0.708 0.402 0.007 L accumbens 302.09 7.74 308.29 7.74 2.268 0.135 0.023 0.320 0.573 0.003 L amygdala 1124.23 17.72 1141.06 17.72 3.947 0.050 0.039 0.448 0.505 0.005 L hippocampus 2978.78 30.05 2990.58 30.05 2.048 0.156 0.021 0.077 0.782 0.001 Cerebellum 7571.77 116.42 7729.65 116.42 3.357 0.070 0.033 0.915 0.341 0.009 FreeSurfer Adults Intracranial volume 1,546,121.38 39,078.81 1,536,555.86 39,078.81 0.030 0.863 0.001 Total brain 1,229,307.07 13,039.49 1,234,999.71 13,039.49 100.313 <0.001 0.654 0.095 0.759 0.002 Total gray matter 613,116.05 8389.40 615,901.38 8389.40 29.021 <0.001 0.354 0.055 0.815 0.001 Total white matter 519,152.95 6951.24 522,287.80 6951.24 104.247 <0.001 0.663 0.102 0.751 0.002 R accumbens 677.13 16.32 672.94 16.32 6.794 0.012 0.110 0.033 0.856 0.001 R amygdala 1656.83 32.96 1686.17 32.96 15.155 <0.001 0.216 0.396 0.532 0.007 R hippocampus 4279.82 55.10 4337.39 55.10 44.457 <0.001 0.447 0.546 0.463 0.010 R cerebellum 53,360.00 827.30 54,256.69 827.30 55.924 <0.001 0.504 0.587 0.447 0.011 L accumbens 498.65 15.94 521.04 15.94 12.782 0.001 0.189 0.985 0.325 0.018 L amygdala 1624.13 28.94 1679.18 28.94 15.604 <0.001 0.221 1.809 0.184 0.032 L hippocampus 4240.54 55.10 4342.42 55.10 40.003 <0.001 0.421 1.709 0.197 0.030 L cerebellum 52,465.04 777.66 53,511.52 777.66 66.129 <0.001 0.546 0.905 0.346 0.016 Adolescents Intracranial volume 1,552,515.32 25,781.08 1,616,127.20 25,781.08 — — — 3.044 0.084 0.030 Total brain 1,276,109.88 8077.09 1,272,935.92 8077.09 370.806 <0.001 0.793 0.076 0.783 0.001 Total gray matter 668,428.50 5354.95 663,327.32 5354.95 158.859 <0.001 0.621 0.447 0.505 0.005 Total white matter 510,897.02 4981.67 513,508.50 4981.67 228.614 <0.001 0.702 0.135 0.714 0.001 R accumbens 719.98 14.04 697.28 14.04 15.984 <0.001 0.141 1.288 0.259 0.013 R amygdala 1713.02 24.17 1703.76 24.17 25.791 <0.001 0.210 0.072 0.789 0.001 R hippocampus 4355.17 46.01 4360.01 46.01 110.710 <0.001 0.533 0.005 0.941 0.000 R cerebellum 57,858.92 674.44 56,291.74 674.44 69.453 <0.001 0.417 2.659 0.106 0.027 L accumbens 573.76 12.40 544.47 12.40 14.288 <0.001 0.128 2.749 0.101 0.028 L amygdala 1681.57 20.26 1667.17 20.26 39.425 <0.001 0.289 0.249 0.619 0.003 L hippocampus 4372.76 48.48 4370.36 48.48 106.960 <0.001 0.524 0.001 0.972 0.000 L cerebellum 57,757.95 685.38 55,647.39 685.38 74.646 <0.001 0.435 4.670 0.033 0.046 R, Right; L, left.
- Table 3.
Statistics for FIRST shape analysis evaluating effect of marijuana between nonusers and daily users
Structure Nonusers Daily users Variance accounted for by group Effect size (r) Mean scalar SD Mean scalar SD F P Adults R accumbens 0.023 0.323 −0.023 0.418 2.081 0.791 0.061 R amygdala −0.040 0.579 0.040 0.541 0.357 1.000 −0.071 R hippocampus −0.048 0.259 0.048 0.374 0.837 0.988 −0.147 L accumbens −0.033 0.325 0.033 0.333 1.903 0.780 −0.100 L amygdala −0.089 0.367 0.089 0.410 0.653 0.976 −0.223 L hippocampus −0.043 0.234 0.043 0.467 0.901 0.993 −0.116 Adolescents R accumbens <0.001 0.325 <0.001 0.352 1.516 0.966 0.000 R amygdala 0.053 0.582 −0.053 0.573 1.777 0.932 −0.181 R hippocampus −0.006 0.421 0.006 0.349 4.687 0.352 0.030 L accumbens 0.037 0.278 −0.037 0.309 1.523 0.988 −0.267 L amygdala −0.049 0.383 0.049 0.437 1.174 0.991 0.256 L hippocampus 0.018 0.295 −0.018 0.323 1.669 0.906 −0.120 R, Right; L, left.
