Table 3 Direct and specific indirect effects of youth demographics, psychological constructs of sensation-seeking, internalizing, and externalizing, and age at first use on lifetime tobacco and cannabis use status

→ Age at first use

− 1.54 (0.09)*

− 1.71, − 1.37

0.21

0.18, 0.25

→ Internalizing

0.18 (0.03)*

0.12, 0.24

1.20

1.12, 1.27

→ Externalizing

0.30 (0.05)*

0.20, 0.40

1.35

1.22, 1.50

→ Sensation seeking

0.15 (0.01)*

0.13, 0.17

1.16

1.14, 1.19

→ Grade

0.66 (0.02)*

0.62, 0.71

1.94

1.85, 2.03

→ Sex

− 0.17 (0.06)*

− 0.29, − 0.06

0.84

0.75, 0.94

→ Hispanic

− 0.27 (0.07)*

− 0.40, − 0.13

0.77

0.67, 0.88

→ Race

− 0.04 (0.04)

− 0.11, 0.03

0.96

0.89, 1.03

→ Internalizing

− 0.11 (0.04)*

− 0.20, − 0.03

0.89

0.82, 0.97

→ Externalizing

− 0.21 (0.05)*

− 0.31, − 0.11

0.81

0.73, 0.90

→ Sensation seeking

− 0.07 (0.02)*

− 0.10, − 0.03

0.94

0.91, 0.97

→ Grade

0.58 (0.03)*

0.52, 0.64

1.78

1.68, 1.89

→ Sex

0.32 (0.07)*

0.18, 0.45

1.37

1.20, 1.57

→ Hispanic

0.13 (0.08)

− 0.03, 0.28

1.14

0.97, 1.32

→ Race

− 0.10 (0.04)*

− 0.18, − 0.02

0.91

0.84, 0.98

Through age at first use

Indirect effect B (SE)

95% CI

→ Internalizing

0.17 (0.07)*

0.05, 0.30

–

–

→ Externalizing

0.33 (0.08)*

0.16, 0.49

–

–

→ Sensation seeking

0.10 (0.03)*

0.05, 0.15

–

–