Table 3.

Cotwin control analysis models between hippocampus volume and substance use composite, drink index, cannabis index, and cigarettes per day scores in women

	Between-pair effect		Within-pair effect
Model	Beta [95% CI]	s.e.	Beta [95% CI]	s.e.
Substance use composite	−182.50 [−333.34 to −40.28]	72.81	−195.62 [−316.37 to −64.60]	63.85
Drink Index	−200.30 [−326.87 to −76.06]	63.62	−89.77 [−175.14 to −7.54]	42.41
Cannabis Index	−36.93 [−108.02 to 38.91]	36.89	−54.51 [−114.71 to 10.17]	31.75
Cigarettes per day	−124.72 [−232.64 to −18.59]	54.10	−119.30 [−197.40 to −27.58]	43.13

Notes: Significant effects are in bold, determined by the nonparametric bootstrap 95% CI around the unstandardized beta estimate not overlapping with zero. CI = confidence interval; s.e. = standard error.