Table 4 Direct and specific indirect effects of youth demographics, psychological constructs of sensation-seeking, internalizing, and externalizing, and age at first use on 30-day tobacco and cannabis use status

→ Age at first use

− 0.49 (0.15)*

− 1.78, − 0.20

0.62

0.46, 0.82

→ Internalizing

0.01 (0.08)

− 0.14, 0.16

1.01

0.87, 1.18

→ Externalizing

0.11 (0.12)

− 0.12, 0.33

1.11

0.89, 1.40

→ Sensation seeking

0.06 (0.03)*

0.01, 0.12

1.06

1.01, 1.13

→ Grade

0.15 (0.07)*

0.01, 0.29

1.16

1.01, 1.34

→ Sex

0.23 (0.16)

− 0.08, 0.53

1.25

0.92, 1.71

→ Hispanic

− 0.11 (0.17)

− 0.44, 0.22

0.90

0.65, 1.25

→ Race

− 0.14 (0.09)

− 0.32, 0.05

0.87

0.73, 1.05

→ Internalizing

− 0.09 (0.05)

− 0.19, 0.00

0.91

0.83, 1.00

→ Externalizing

− 0.11 (0.06)

− 0.23, 0.01

0.90

0.80, 1.01

→ Sensation seeking

− 0.02 (0.02)

− 0.05, 0.01

0.99

0.96, 1.01

→ Grade

0.67 (0.03)*

0.62, 0.73

1.96

1.86, 2.07

→ Sex

0.30 (0.08)*

0.15, 0.46

1.35

1.16, 1.58

→ Hispanic

0.03 (0.09)

− 0.14, 0.20

1.03

0.87, 1.22

→ Race

− 0.13 (0.05)*

− 0.22, − 0.03

0.88

0.80, 0.97

Through age at first use

Indirect effect B (SE)

95% CI

→ Internalizing

0.04 (0.03)

− 0.01, 0.10

–

–

→ Externalizing

0.05 (0.03)

− 0.01, 0.12

–

–

→ Sensation seeking

0.01 (0.01)

− 0.01, 0.02

–

–