Table 2:
Sample Size and Age Descriptives by Measure, Measure Descriptives, and Mean Comparisons
| Measure | Sex | Sample | Mean age at assessment (SD) | Sample Size | Mean Symptom Count (SD) [residualized SD] | Test of between sample differences χ2 (p) | Test of between gender differences χ2 (p) | ||
|---|---|---|---|---|---|---|---|---|---|
| Total | MZ | DZ | |||||||
| ADHD | M | MN | 13.6 (2.7) | 1730 | 1118 | 612 | 1.39 (1.98) [0.67] | 2.3 (.13) | 57.2 (< .001) |
| CO | 14.9 (2.2) | 1167 | 594 | 573 | 1.25 (2.38) [0.71] | 10.7 (.001) | |||
| F | MN | 13.8 (2.8) | 1867 | 1185 | 682 | 0.87 (1.59) [0.58] | 0.5 (.48) | ||
| CO | 15.0 (2.2) | 1310 | 723 | 587 | 0.94 (1.99) [0.63] | ||||
| Alcohol Dependence | M | MN | 17.5 (0.6) | 1628 | 1042 | 586 | 0.65 (1.44) [0.54] | 6.3 (.01) | 42.6 (< .001) |
| CO | 18.0 (1.6) | 1012 | 521 | 491 | 0.83 (1.53) [0.56] | 10.6 (.001) | |||
| F | MN | 17.6 (0.7) | 1771 | 1137 | 634 | 0.31 (1.05) [0.40] | 28.4 (< .001) | ||
| CO | 18.1 (1.7) | 1175 | 649 | 526 | 0.60 (1.30) [0.52] | ||||
| Conduct Disorder | M | MN | 17.5 (0.6) | 1165 | 776 | 389 | 1.12 (1.58) [0.61] | 1.4 (.24) | 180.4 (< .001) |
| CO | 18.1 (1.5) | 1012 | 522 | 490 | 1.21 (1.43) [0.57] | 74.3 (.001) | |||
| F | MN | 17.6 (0.7) | 1308 | 842 | 466 | 0.27 (0.73) [0.36] | 74.7 (< .001) | ||
| CO | 18.3 (1.6) | 1177 | 650 | 527 | 0.63 (0.96) [0.47] | ||||
Note: Descriptives are split by measure and sex, including age, number of individuals, and symptom counts (raw mean and standard deviation and residualized standard deviation). Sample size columns refer to number of individuals. ADHD=Attention Deficit Hyperactivity Disorder; M=Male, F=Female; MZ=Monozygotic; DZ=Dizygotic; MN=Minnesota; CO=Colorado; SD=Standard Deviation. Residualized SD refers to the standard deviation of the residuals which were analyzed in the externalizing psychopathology factor model, symptom counts were regressed on age, age2, age × cohort, cohort, and sex. Test of between state differences refers to testing equivalence of symptom count means in Colorado and Minnesota within each gender. Test of between gender differences refers to testing equivalence of symptom count means in males and females within each state.