Table 2.

Bivariate correlations between circadian preference, reward-related brain response, and substance involvement

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15c	16c
1 Circadian preference - 20	1.00	0.56**	0.15	−0.02	0.10	−0.03	−0.04	−0.26*	0.06	−0.23*	− 0.22†	−0.26*	−0.16	−0.22*	−0.21†	−0.35**
2 Circadian preference - 22		1.00	0.06	−0.14	0.02	−0.09	−0.05	−0.12	0.00	−0.15	−0.05	−0.17	0.05	−0.25*	−0.11	−0.25*
3 Anticipation - mPFC - 20			1.00	−0.14	0.52**	−0.05	0.08	−0.05	0.09	0.03	−0.04	−0.08	−0.07	0.15	−0.00	−0.01
4 Anticipation - mPFC - 22				1.00	−0.10	0.65**	0.19†	0.52**	0.07	0.23*	0.05	0.07	0.13	−0.00	−0.02	0.02
5 Anticipation - VS - 20					1.00	−0.05	0.09	0.12	−0.01	0.13	−0.04	0.03	−0.10	−0.03	0.02	−0.06
6 Anticipation - VS - 22						1.00	0.24*	0.29**	0.05	0.54**	0.04	0.03	0.07	0.12	0.02	0.03
7 Win - mPFC - 20							1.00	0.26*	0.47**	0.05	0.00	−0.02	−0.06	−0.06	0.03	−0.01
8 Win - mPFC - 22								1.00	−0.01	0.40**	0.25*	0.34**	0.17	0.26*	0.21*	0.19†
9 Win - VS - 20									1.00	−0.09	0.01	−0.03	−0.11	−0.12	−0.04	−0.18†
10 Win - VS - 22										1.00	0.15	0.21†	0.04	0.16	−0.07	−0.01
11 Alcohol dependence - 20 a											1.00	0.54***	0.39***	0.43***	0.26*	0.35**
12 Alcohol dependence - 22												1.00	0.38***	0.44***	0.30**	0.33**
13Alcohol use – 20b													1.00	0.61***	0.33**	0.35***
14Alcohol use – 22b														1.00	0.27*	0.37***
15 Cannabis use – 20c															1.00	0.86***
16 Cannabis use – 22c																1.00

NOTES: Circadian preference is based on the Composite Scale of Morningness, with higher scores indicating greater morningness.

^aAlcohol dependence (Alcohol Dependence Scale) was available for n=70 at age 20.

^bAlcohol use data was square-root transformed prior to analyses.

^cGiven the ordinal nature of the cannabis use variable (0=no use, 1–19 days per month, 2=20+ days per month), Spearman’s correlations are reported for all analyses involving the cannabis use variable.

^†p>0.05,

^*p<0.05,

^**p<0.01,

^***p<0.001