Table 2.
Sample Characteristics and Heritabilities
| Total(%) (N=1122) | Female (N=720) | Male (N=402) | Heritability^ | P-Value | Age* | Sex* | Age × Sex* | Age2* | Age2 × Sex* | Household | |
|---|---|---|---|---|---|---|---|---|---|---|---|
| MDD# | 387 (35) | 286 | 101 | 0.393 | 3.7 × 10−6 | 0.719 | 9.3 × 10−5 | 0.317 | 0.063 | 0.484 | 0.000 |
| Recurrent MDD | 215 (19) | 157 | 58 | 0.463 | 4.0 × 10−6 | 0.541 | 0.010 | 0.790 | 0.225 | 0.525 | 0.023 |
| Early-Onset MDD | 135 (12) | 93 | 42 | 0.485 | 8.5 × 10−5 | 0.029 | 0.053 | 0.413 | 0.352 | 0.078 | 0.018 |
| Early-Recurrent MDD | 105 (9) | 62 | 28 | 0.516 | 4.8 × 10−5 | 0.259 | 0.037 | 0.577 | 0.473 | 0.081 | 0.000 |
| Alcohol Disorders (AD) | 378 (34) | 138 | 240 | 0.301 | 2.6 × 10−4 | 0.652 | 4.7 × 10−27 | 0.007 | 0.008 | 0.126 | 0.001 |
| Drug Disorders (DD) | 85 (8) | 28 | 57 | 0.603 | 3.3 × 10−3 | 5.4 × 10−7 | 1.1 × 10−9 | 0.503 | 1.1 × 10−4 | 0.340 | 0.000 |
^
heritability estimate (h2) for full sample;
*
p-value for covariate in heritability analysis;
#
all estimates are for lifetime diagnoses of major depressive disorder (MDD), multi-episode MDD (recurrent MDD), early-onset MDD (i.e., initial depressive episode before age 25), alcohol abuse and dependence (AD), and drug abuse and dependence (DD)