Table 2.
Parameter Estimates From Behavioral-Genetic Models
| Parameter | Model 1 (interaction) | Model 2 (interaction: continuous SES) | Model 3 (interaction: dichotomous SES) |
|---|---|---|---|
| Intercept | |||
| Menarche | 12.339 (0.061) | 12.34 (0.062) | 12.343 (0.074) |
| CES-D | 0.118 (0.047) | 0.117 (0.048) | 0.160 (0.058) |
| Covariate | |||
| SES → Menarche (sM) | 0.009 (0.020) | −0.009 (0.02) | −0.020 (0.098) |
| Race → Menarche (rM) | −0.171 (0.102) | −0.169 (0.103) | −0.167 (0.101) |
| SES → CES-D (sD) | −0.051 (0.015) | −0.050 (0.016) | −0.162 (0.076) |
| Race → CES-D (rD) | 0.145 (0.079) | 0.149 (0.079) | 0.169 (0.079) |
| Genetic and environmental influences on menarche | |||
| aM | 1.044 (0.054) | 1.067 (0.054) | 1.067 (0.076) |
| a′M | — | −0.015 (0.022) | −0.034 (0.106) |
| eM | 0.895 (0.046) | 0.870 (0.048) | 0.902 (0.066) |
| e′M | — | 0.020 (0.019) | −0.032 (0.091) |
| Menarche → CES-D | |||
| aMD | −0.108 (0.063) | −0.017 (0.064) | 0.033 (0.085) |
| a′MD | — | −0.038 (0.024) | −0.289 (0.125) |
| eMD | 0.041 (0.056) | −0.008 (0.059) | −0.113 (0.076) |
| e′MD | — | 0.050 (0.022) | 0.326 (0.110) |
| Residual genetic and environmental influences on CES-D | |||
| aD | 0.774 (0.049) | 0.787 (0.049) | 0.812 (0.060) |
| a′D | — | −0.029 (0.020) | −0.080 (0.104) |
| eD | 0.742 (0.040) | 0.725 (0.041) | 0.711 (0.052) |
| e′D | — | 0.003 (0.016) | 0.011 (0.081) |
Note: See Figure 1a and 1b for path diagrams. Standard errors are shown in parentheses; boldface indicates parameters significantly different from 0 (at p < .05). For Models 1 and 2, SES centered at parental education equals 5. For Model 3, SES dichotomized into less than a college degree—parental education equals less than 7 (reference group) versus a college degree or higher. SES = socioeconomic status; CES-D = Center for Epidemiological Studies–Depression Scale.