Table 1.
Demographic Characteristics of Attention Deficit Hyperactivity Disorder (ADHD) and Comparison Probands and Their First-Degree Relatives
| ADHD Probands |
Comparison Probands |
Analysis | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Age (years) | Age (years) | ||||||||
| N | Mean | SD | N | Mean | SD | Test | Df | p | |
| Age at last assessment (years) | |||||||||
| Probands | 208 | 21.6 | 3.5 | 196 | 22.7 | 3.5 | t=3.1 | 402 | 0.002 |
| Mothers | 208 | 40.0 | 5.3 | 196 | 41.9 | 5.3 | t=3.6 | 402 | <0.001 |
| Fathers | 206 | 42.8 | 6.2 | 190 | 44.0 | 5.9 | t=1.9 | 394 | 0.05 |
| Siblings | 282 | 21.8 | 6.4 | 254 | 22.0 | 6.2 | t=0.3 | 534 | 0.8 |
| Family Socioeconomic Status | 208 | 1.8 | 0.9 | 196 | 1.5 | 0.8 | z=−3.2 | 1 | 0.001 |
| N | % | N | % | ||||||
| Proband sex (male) | 208 | 112 | 54 | 196 | 105 | 54 | χ2=0.003 | 1 | 1.0 |