Table 1.
Descriptive information for study variables.
| N | % | M | SD | |
|---|---|---|---|---|
| Person-level variables (n=773) | ||||
| Female | 434 | 56 | ||
| Race/ethnicity | ||||
| Non-Hispanic White | 425 | 55 | ||
| Non-Hispanic Asian | 137 | 18 | ||
| Non-Hispanic Other | 142 | 18 | ||
| Hispanic | 69 | 9 | ||
| Age at enrollment | 21.11 | 1.70 | ||
| Proportion of months of alcohol use | .78 | .29 | ||
| Proportion of months of marijuana use | .36 | .37 | ||
| Person average quantity/frequency of alcohol use across alcohol-use months (person mean of monthly measures)a | 0.02 | 0.82 | ||
| Person average marijuana use occasions across marijuana-use months (person mean of monthly measures) | 1.18 | 1.76 | ||
| Proportions of months for patterns of use | ||||
| Alcohol-only | 0.46 | 0.34 | ||
| Marijuana-only | 0.04 | 0.12 | ||
| CAM | 0.10 | 0.16 | ||
| SAM | 0.21 | 0.30 | ||
| Time-varying (months) (n=15,448) | ||||
| Negative alcohol consequence (n=11,882) | 2.63 | 3.76 | ||
| Depressive symptoms | 1.41 | 1.49 | ||
| Poor health | 1.56 | 1.02 | ||
| Quantity/frequency of alcohol usea | 0.00 | 1.00 | ||
| Marijuana use occasions | 1.07 | 1.89 | ||
| Substance use pattern in a given month | ||||
| Neither alcohol nor marijuana | 2,873 | 19 | ||
| Alcohol-only | 7,409 | 48 | ||
| Marijuana-only | 569 | 4 | ||
| CAM | 1,597 | 10 | ||
| SAM | 3,000 | 19 |
Note. SAM=simultaneous alcohol and marijuana; CAM=concurrent alcohol and marijuana but not simultaneous use.
a
Sum of z-scores for frequency of any alcohol use and heavy episodic drinking and number of drinks consumed in a typical week.