Table I.
Twin correlations, univariate ACE, ADE and sub-model estimates for stress variables & Common EF
| Twin Correlations | Standardized Paths | Model Fit | Diff test p | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Stress Variable | MZ | DZ | A | C/D | E | χ2 | df | p | CFI | RMSEA | ||
| 1. Age 23 Dependent | ACE | .42 [.08] | .16 [.09] | .63 [.13] | .00 [20] | .77 [.05] | 8.47 | 10 | .58 | 1.0 | .00 | - |
| ADE | - | - | .46 [.27] | .45 [.28] | .77 [.05] | 8.25 | 10 | .60 | 1.0 | .00 | - | |
| 2. Age 23 Dependent LT | ACE | .42 [.13] | .18 [.18] | .58 [.22] | .00 [.25] | .76 [.08] | 7.16 | 6 | .31 | .94 | .03 | - |
| ADE | - | - | .32 [.29] | .56 [.30] | .74 [.08] | 6.98 | 6 | .32 | .95 | .03 | - | |
| AE | - | - | .63 [.11] | - | .76 [.08] | 7.14 | 7 | .41 | .99 | .01 | .99 | |
| E | - | - | - | - | .98 [.01] | 18.41 | 8 | .02 | .59 | .13 | .00 | |
| 3. Age 29 Dependent | ACE | .23 [.10] | .08 [.11] | .46 [.18] | .00 [.20] | .89 [.05] | 6.81 | 10 | .74 | 1.0 | .00 | - |
| AE | - | - | .46 [.11] | - | .89 [.05] | 6.84 | 11 | .81 | 1.0 | .00 | .85 | |
| E | - | - | - | - | 1.0 [.00] | 5.61 | 12 | .43 | .89 | .10 | .02 | |
| 4. Age 29 Dependent LT | ACE | .33 [.12] | .17 [.14] | .58 [.24] | .02 [.30] | .81 [.07] | 6.35 | 6 | .39 | .96 | .02 | - |
| AE | - | - | .58 [.11] | - | .81 [.07] | 6.32 | 7 | .50 | 1.0 | .00 | .99 | |
| E | - | - | - | 1.0 [.00] | 15.52 | 8 | .05 | .23 | .07 | .00 | ||
| 5. Age 23 Independent | ACE | −.03 [.15] | −.04 [.16] | 0 [.15] | .00 [.12] | 1.0 [.03] | 3.57 | 6 | .74 | 1.0 | .00 | - |
| 6. Age 23 Independent LT | ACE | .62 [.08] | .25 [.12] | .78 [.11] | .00 [.21] | .63 [.06] | 5.30 | 6 | .51 | 1.0 | .00 | - |
| ADE | - | - | .61 [.30] | .50 [.32] | .62 [.07] | 5.02 | 6 | .54 | 1.0 | .00 | - | |
| AE | - | - | .78 [.05] | - | .63 [.06] | 5.26 | 7 | .63 | 1.0 | .00 | .62 | |
| 7. Age 29 Independent | ACE | .27 [.15] | .05 [.15] | .48 [.33] | .00 [.21] | .88 [.07] | 9.25 | 6 | .16 | .00 | .06 | - |
| AE | - | - | .48 [.16] | - | .87 [.08] | 9.26 | 7 | .23 | .00 | .04 | .99 | |
| E | - | - | - | - | 1.0 [.01] | 12.37 | 8 | .14 | .00 | .06 | .08 | |
| 8. Age 29 Independent LT | ACE | .46 [.11] | .29 [.13] | .53 [.26] | .37 [.25] | .75 [.07] | 4.43 | 6 | .62 | 1.0 | .00 | - |
| AE | - | - | .66 [.08] | - | .73 [.07] | 4.65 | 7 | .70 | 1.0 | .00 | .62 | |
| CE | - | - | - | .59 [.07] | .79 [.05] | 5.15 | 7 | .64 | 1.0 | .00 | .40 | |
| E | - | - | - | - | .99 [.01] | 24.41 | 8 | .00 | .40 | .11 | .00 | |
| 9. Age 23 Total Events | ACE | .30 [.11] | −.09 [.16] | .67 [.07] | .00 [.07] | .73 [.05] | 11.93 | 10 | .29 | .96 | .03 | - |
| ADE | - | .00 [.29] | .70 [.21] | .71 [.05] | 9.69 | 10 | .46 | 1.0 | .00 | - | ||
| 10. Age 29 Total Events | ACE | .46 [.08] | .17 [.11] | .67 [.12] | .00 [.17] | .74 [.05] | 7.92 | 10 | .64 | 1.0 | .00 | - |
| 11. Age 23 Common EF | ACE | .85 [.04] | .46 [.09] | .90 [.08] | .20 [.25] | .39 [.07] | 420.26 | 320 | .00 | .95 | .04 | - |
| 12. Age 29 Common EF | ACE | .93 [.04] | .27 [.12] | .96 [.02] | .00 [.05] | .29 [.08] | 222.68 | 142 | .00 | .92 | .06 | - |
| ADE | - | - | .41 [.34] | .87 [.25] | .28 [.08] | 219.13 | 142 | .00 | .92 | .06 | - | |
Standard errors in brackets, bootstrapped for the ACE and ADE paths. Twin correlations do not include sex as a covariate, but sex was included as a covariate in the twin models; ACE and ADE paths may not sum to 1 to the extent that sex accounted for variance (estimates not shown). Significance of twin correlation determined with z-tests (Wald tests); significance of ACE and ADE influences determined with 1 df chi-square difference tests (diff test p) shown in rows with sub-models below full ACE model. All difference tests were compared to the full ACE model, so are based on a chi-square with 1 df for AE or CE models, and with 2 df for E models. C was not estimated for Common EF age 29 model. See Supplemental Figures S2 and S3 and Supplemental SVI for full results of the age 29 EF model, and Friedman et al (2016) for the age 23 EF model. EF = executive function; MZ = monozygotic twins, DZ = dizygotic twins; A = additive genetic; C = shared environmental; D = dominant genetic; E = nonshared environmental variance (including measurement error); LT = lifetime; 23 and 29 indicate mean ages of assessment. Boldface type indicates p< .05. Dashes indicate the parameter was not estimated.