Table 4.
Model fit statistics, standardized factor loadings, and factor correlations for models of drug use disorder.
| Statistics, loadings, and correlations | Bifactor | Correlated Factors | One-Factor | |||
|---|---|---|---|---|---|---|
| Statistic | Model fit | Model fit | Model fit | |||
| Chi-square (WLSMV) | 151.024 | 264.586 | 381.109 | |||
| Degrees of freedom | 61 | 76 | 83 | |||
| Comparative fit index | 0.991 | 0.980 | 0.969 | |||
| Tucker-Lewis index | 0.985 | 0.975 | 0.963 | |||
| RMSEA (90% CI) | 0.006 (0.005–0.008) | 0.008 (0.007–0.009) | 0.010 (0.009–0.011) | |||
| Standardized factor loading (SE) | General | Prescription | Illicit | Prescription | Illicit | General |
| Prescription opioids | 0.804 (0.020) | 0.389 (0.032) | – | 0.901 (0.009) | – | 0.827 (0.012) |
| Sedatives | 0.834 (0.023) | 0.361 (0.033) | – | 0.901 (0.009) | – | 0.857 (0.015) |
| Heroin | 0.798 (0.031) | – | −0.076 (0.068) | – | 0.772 (0.029) | 0.760 (0.029) |
| Cannabis | 0.596 (0.026) | – | 0.625 (0.044) | – | 0.762 (0.015) | 0.751 (0.015) |
| Cocaine/crack | 0.793 (0.022) | – | 0.185 (0.066) | – | 0.820 (0.013) | 0.815 (0.013) |
| Stimulants | 0.813 (0.021) | – | 0.142 (0.062) | – | 0.832 (0.015) | 0.820 (0.015) |
| Club drugs | 0.831 (0.034) | – | 0.369 (0.074) | – | 0.919 (0.017) | 0.911 (0.018) |
| Hallucinogens | 0.863 (0.032) | – | 0.375 (0.073) | – | 0.951 (0.014) | 0.943 (0.014) |
| Inhalants | 0.825 (0.042) | – | 0.266 (0.090) | – | 0.882 (0.029) | 0.872 (0.029) |
| Factor correlation (95% CI) | – | .87 (0.84-0.89) | – | |||
Note. Loadings constrained to equality can vary slightly in standardized estimates; bold font indicates significant factor loading/correlation, p<.001; italic font indicates significant factor loading/correlation, p<.05.