Table 2.
Demographics: Alcohol and Cannabis Use Initiators
| Total Sample | A Alcohol-only Users |
B Cannabis Users (Total) |
C Infrequent Cannabis Users |
D Moderately frequent Cannabis Users |
A vs. B | C vs. D | A vs. C vs. D | |
|---|---|---|---|---|---|---|---|---|
| N= | 86 | 39 | 47 | 29 | 18 | -- | -- | -- |
| Age (Pre-initiation) | 16.38 (2.57) | 16.36 (2.4) | 16.40 (2.7) | 16.8 (2.4) | 15.8 (27) | F=.007; p=.933 | F=1.40, p=.244 | F=.764, p=.469 |
| Age Range (Pre-initiation) | 10.72–24.05 | 11.74–20.96 | 10.72–24.05 | 11.88–24.05 | 10.72–20.51 | -- | -- | -- |
| Age (Post-Initiation) | 19.23 (2.44) | 19.03 (2.2) | 19.40 (2.6) | 19.4 (2.8) | 19.4 (2.4) | F= .492; p=.485 | F=0.006, p=.940 | F=.246, p=.782 |
| Age Range (Post-Initiation) | 14.01–26.09 | 14.01–22.59 | 14.17–26.09 | 14.24–26.09 | 14.17–23.42 | -- | -- | -- |
| Gender (#M; #F; #Other) | 47:39:0 | 19:20:0 | 28:19:0 | 18:11:0 | 10:8:0 | X2=1.01, p=.314 | X2= .196, p=.763 | X2= 1.20, p=.548 |
| WASI-estimated IQa (Pre-initiation) | 115.0 (11.5) | 116.6 (9.8) | 113.7 (12.5) | 113.2 (12.8) | 114.5 (12.3) | F=1.40, p=.240 | F=.123, p=.727 | F=.768, p=.467 |
| White:Non-White Ethnicity | 78:8 | 38:1 | 40:7 | 24:5 | 16:2 | X2=4.35, p=.227 | X2=2.14, p=.543 | X2=7.37, p=.288 |
| Parental Education (averaged; years) | 15.96 (1.99) | 16.4 (2.1) | 15.6 (1.9) | 16.1 (1.9)` | 14.8 (1.4) | F=3.21, p=.077 | F=5.64, p=.022 | F=4.09, p=.020 |
| Family Income US Dollars (study baseline) | 95537.5 (66279.6) | 111944.4 (89381.0) | 82113.6 (34035.7) | 79038.5 (30855.1) | 86555.6 (38661.8) | F=4.17, p=.044 | F=.513, p=.478 | F=2.13, p=.125 |
| Past six months daily nicotine use frequency Pre-initiationb | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | -- | -- | -- |
| Past six months daily nicotine use frequency Post-initiationb | 0.28 (1.61) | 0.03 (0.16) | 0.57 (2.32) | 0.00 (0.00) | 1.50 (3.62) | F=2.17, p=.144 | F=5.05, p=.030 | F=5.83, p=.004 |
| Alcohol Use Frequency Past 12 months, Pre-Initiationc | 0.28 (0.66) | 0.00 (0.00) | 0.75 (0.92) | 0.90 (0.97) | 0.50 (0.80) | F=17.38, p=.000 | F=1.45, p=.238 | F=10.28, p=.000 |
| Alcohol Use Frequency Past 12 months Post-Initiationc | 1.94 (1.14) | 1.41 (0.97) | 2.38 (1.10) | 2.34 (1.17) | 2.44 (0.98) | F=18.71, p=.000 | F=.090, p=.765 | F=9.31, p=.000 |
| Cannabis Use Frequency Past 12 months Post-initiationc | 0.81 (1.82) | 0.00 (0.00) | 1.49 (0.95) | 0.86 (0.35) | 2.5 (0.71) | F=95.14, p=.000 | F=112.2, p=.000 | F=267.71, p=.000 |
| Study visits before initiation | 1.99 (0.91) | 1.87 (0.83) | 2.09 (0.97) | 2.10 (0.94) | 2.10 (1.06) | F=1.16, p=.284 | F=.026, p=.872 | F=.590, p=.567 |
Unless otherwise indicated, values represent means and, in parentheses, one standard deviation.
a
WASI-estimated IQs are based on four subtests: Vocabulary, Matrix Reasoning, Similarities and Block Design
b
Nicotine use = the number of reported uses per day in the past six months assessed by the Achenbach self report inventories.
c
Alcohol and cannabis use frequencies for the twelve months prior to each assessment were assessed with the Personal Experiences Inventory (PEI): 0=0 use; 1=1–5 times; 2= 6–20 times; 3= 21–49 times; 4=50–99 times.