Table 4.
Fit and comparison tests of univariate twin models for onset of regular cannabis use, insomnia, and insomnia with short sleep on weekdays (<6 h)
| Measure | Model | Model fit | Standardized paths | χ 2 test with full ACE model | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| χ 2 | df | P | RMSEA | CFI | A | C | E | df | χ 2 | P | ||
| Onset of regular cannabis use | ACE | 11.332 | 22 | 0.9697 | 0.000 | 1 | 0.708 | 0.486 | 0.512 | – | – | – |
| AE | 14.557 | 23 | 0.9098 | 0.000 | 1 | 0.872 | – | 0.489 | 1 | 3.747 | 0.0529 | |
| CE | 22.304 | 23 | 0.5019 | 0.000 | 1 | – | 0.814 | 0.580 | 1 | 13.060 | <0.001 | |
| AC | 50.879 | 23 | 0.0007 | 0.080 | 0.937 | 1 | 0 | – | 1 | 47.438 | <0.001 | |
| Insomnia | ACE | 3.553 | 12 | 0.9902 | 0.000 | 1 | 0.664 | 0 | 0.748 | – | – | – |
| AE | 3.554 | 13 | 0.9951 | 0.000 | 1 | 0.664 | – | 0.748 | 1 | 0.00 | 0.9986 | |
| CE | 9.706 | 13 | 0.7178 | 0.000 | 1 | – | 0.583 | 0.813 | 1 | 6.145 | 0.0132 | |
| AC | 31.932 | 13 | 0.0025 | 0.088 | 0.497 | 1 | 0 | – | 1 | 28.351 | <0.001 | |
| Insomnia with short sleep on weekdays (<6 h) | ACE | 17.461 | 32 | 0.9827 | 0.000 | 1 | 0.610 | 0 | 0.793 | – | – | – |
| AE | 17.587 | 33 | 0.9871 | 0.000 | 1 | 0.610 | – | 0.793 | 1 | 0.00 | 1.00 | |
| CE | 22.182 | 33 | 0.9235 | 0.000 | 1 | – | 0.532 | 0.847 | 1 | 5.802 | 0.0160 | |
| AC | 109.127 | 33 | 0.00 | 0.111 | 0 | 1 | 0 | – | 1 | 115.650 | <0.001 |
Models in bold indicate the best fitting model based on χ 2 difference tests.