Table 4.

Linear regression between smoking behavior and structural measures

Smoking occasions/dayJoints/occasionJoints/weekSmoking days/week
r2pr2pr2pr2p
GMd
    R accumbens0.0500.1710.0590.1370.0550.1560.0490.174
    R amygdala0.0710.1000.0350.2510.0070.6100.0270.321
    L accumbens0.2550.001*0.2350.002*0.1410.0200.1150.035
    L amygdala0.1910.005*0.0610.1300.0210.3800.0420.212
Volume
    R accumbens0.0150.4500.0970.0510.0270.3070.0030.714
    R amygdala0.0090.5580.0690.1000.0720.0940.0080.565
    L accumbens0.0820.0730.1450.0150.0660.1100.0480.230
    L amygdala0.0000.8670.0000.8850.0010.8310.0010.835
Shape
    R accumbens0.2310.002*0.2650.001*0.2320.0180.2320.002*
    R amygdala0.296< 0.001*0.414< 0.0001*0.1860.001*0.1860.007*
    L accumbens0.1580.012*0.1700.009*0.1200.5360.1200.031
    L amygdala0.0040.6850.0060.6430.0160.4390.0020.785
  • Values of gray matter density (GMd), volume, and shape were entered into linear regressions with the four measures of marijuana use, yielding the reported r2 and p-values. p < 0.05 uncorrected are in bold; an asterisk indicates that these values met correction for multiple comparisons across four regions (e.g., p < 0.0125).