Table 1.
Demographic characteristics of the study sample.
| Variables | NU | AUI | CUI |
|---|---|---|---|
| Sample size, n | 128 | 207 | 168 |
| Age at imaging collection, mean (SD) | 16.41 (1.74) | 16.36 (1.73) | 16.43 (1.49) |
| Onset age | – | 17.14 (1.71) | 17.17 (1.50) |
| Gender (female), No. (%) | 68 (53) | 101 (49) | 86 (51) |
| Race, No. (%)* | |||
| White | 81 (63) | 169 (82) | 129 (77) |
| Black | 23 (18) | 15 (7) | 17 (10) |
| Other | 24 (19) | 23 (11) | 22 (13) |
| Family income, No. (%)* | |||
| <$35,000 | 22 (17) | 10 (5) | 12 (7) |
| $35,000–$99,999 | 41 (32) | 63 (31) | 44 (27) |
| ≥$100,000 | 64 (50) | 129 (64) | 108 (66) |
| Parental education, No. (%) | |||
| ≤12 years | 13 (10) | 7 (3) | 9 (5) |
| 13–16 years | 49 (38) | 85 (41) | 72 (43) |
| ≥17 years | 66 (52) | 115 (56) | 87 (52) |
| Parental marital status (Yes), No. (%) | 93 (73) | 166 (80) | 130 (77) |
| Number of controllable NLEs, No. (%)* | |||
| 0 | 67 (52) | 73 (35) | 50 (30) |
| 1 | 38 (30) | 63 (31) | 49 (29) |
| ≥2 | 23 (18) | 71 (34) | 69 (41) |
| Number of uncontrollable NLEs, No. (%) | |||
| 0 | 77 (60) | 119 (58) | 94 (56) |
| 1 | 36 (28) | 50 (24) | 47 (28) |
| ≥2 | 15 (12) | 38 (18) | 27 (16) |
AUI: alcohol use initiation; CUI: cannabis use initiation; NLEs: negative life events; NU: non-using; SD: standard deviation.
Onset age: self-reported age at substance use initiation; available only for AUI and CUI.
*
p < 0.05.
Compared to the NU group, the AUI group had more White participants; both AUI and CUI groups had more participants from high income families (≥$100k) and more controllable NLEs than NUs.