Table 3.
Best-fitting Models for Twin and Family/Adoption Studies and Impulsivity Subscale Analyses
| Model | χ2 | df | p-value | AIC | A | C | D | E |
|---|---|---|---|---|---|---|---|---|
| Analyses of All Data | ||||||||
| ACDE | 1271.14 | 440 | <.001 | 391.14 | .38 | .00 | .12 | .50 |
| ACE | 1291.59 | 441 | <.001 | 409.59 | .49 | .00 | -- | .51 |
| ADE | 1271.14 | 441 | <.001 | 389.14 | .38 | -- | .12 | .50 |
| AE | 1291.59 | 442 | <.001 | 407.59 | .49 | -- | -- | .51 |
| CE | 2225.55 | 442 | <.001 | 1341.55 | -- | .34 | -- | .66 |
| Analyses of Twin Studies Only | ||||||||
| ACE | 1233.30 | 408 | <.001 | 417.30 | .49 | .00 | -- | .51 |
| ADE | 1212.92 | 408 | <.001 | 396.92 | .34 | -- | .16 | .50 |
| AE | 1233.30 | 409 | <.001 | 415.30 | .49 | -- | -- | .51 |
| CE | 2029.23 | 409 | <.001 | 1211.23 | -- | .36 | -- | .64 |
|
Subscale Analyses Lack of planning |
||||||||
| ACDE | 346.10 | 236 | <.001 | −125.89 | .29 | .00 | .12 | .59 |
| ACE | 357.60 | 237 | <.001 | −116.40 | .40 | .00 | -- | .60 |
| ADE | 346.10 | 237 | <.001 | −127.89 | .29 | -- | .12 | .59 |
| AE | 357.60 | 238 | <.001 | −118.40 | .40 | -- | -- | .60 |
| CE | 589.12 | 238 | <.001 | 113.12 | -- | .24 | -- | .76 |
|
Sensation Seeking ACDE |
356.88 | 119 | <.001 | 118.88 | .29 | .02 | .16 | .53 |
| ACE | 362.78 | 120 | <.001 | 122.78 | .47 | -- | .00 | .53 |
| ADE | 356.926 | 120 | <.001 | 116.926 | .34 | -- | .13 | .53 |
| AE | 362.776 | 121 | <.001 | 120.78 | .47 | -- | -- | .53 |
| CE | 655.875 | 121 | <.001 | 413.875 | -- | .34 | -- | .66 |
| Lack of Perseverance | ||||||||
| ACE | 251.46 | 30 | <.001 | 191.46 | .67 | .00 | -- | .33 |
| ADE | 225.72 | 30 | <.001 | 165.72 | .37 | -- | .32 | .31 |
| AE | 251.46 | 31 | <.001 | 186.46 | .67 | -- | -- | .33 |
| CE | 756.49 | 31 | <.001 | 649.49 | -- | .44 | -- | .56 |
Note. AIC= Akaike Information Criterion; A= additive genetic effects; C= shared environmental effects; E= nonshared environmental effects; D=nonadditive genetic effects. Best fitting model is in bold.