Table 5.

Mediation of the effect of parental FH of substance misuse on personal substance use through DD

Mediation Relationship X→M→Y	Direct and Total Effects		Adjusted R2	Indirect Effect	Bootstrapping
					Lower BC 95%CI	Upper BC 95% CI
Model 1:	b(YX)	1.31***
FH of Smoking → PCAk → Smoking	b(MX)	.40***	.09***	.10	.04	.18
	b(YM.X)	.26***
	b(YX.M)	1.21***
Model 2:	b(YX)	1.82*
FH of Alcohol → PCAk → AUDIT	b(MX)	.38*	.02**	.15	.02	.43
	b(YM.X)	.40*
	b(YX.M)	1.67*
Model 3:	b(YX)	2.15***
Overall FH of Substance Misuse → PCAk → Smoking	b(MX)	.71***	.08***	.19	.08	.35
	b(YM.X)	.26***
	b(YX.M)	1.96***
Model 4:	b(YX)	2.87***
Overall FH of Substance Misuse → PCAk → Drug Experimentation	b(MX)	.71***	.08***	.10	.02	.22
	b(YM.X)	.14*
	b(YX.M)	2.78***
Model 5:	b(YX)	.63**
Overall FH of Substance Misuse → PCAk → Marijuana Usea	b(MX)	.72***	.03***	.05	.01	.13
	b(YM.X)	.08*
	b(YX.M)	.57**

Notes. Number of bootstrapped resamples = 5,000; FH = family history; DD = delay discounting; AUDIT = Alcohol Use Disorders Identification Test; Drug Experimentation = number of illicit substances ever used for those participants who endorsed ever using any illicit drug; PCAk = delay discounting factor score from principal components analysis; DV = dependent variable; BC = bias corrected; Y = dependent variable; M = mediator; b(YX) = direct effect of X on Y; b(MX) = direct effect of X on M; b(YM.X) = direct effect of M on Y, controlling for X; b(YX.M) = direct effect of X on Y, controlling for M. The indirect effect of X on Y through M is calculated by subtracting the direct effect of X on Y, controlling for M (i.e., b[YX.M]) from the total effect of X on Y (i.e., b[YX]).

^an = 730.

^***p < 0.001;

^**p < 0.01;

^*p < 0.05.