Table 1.
Sample characteristics
| ADHD | ADHD | Normal | |||||
|---|---|---|---|---|---|---|---|
| Probands (N = 56) | Affected siblings (N = 23) | Controls (N = 105) | Statistics | ||||
| M | SD | M | SD | M | SD | ||
| χ2 | |||||||
| Male (%) | 78.6 | 47.8 | 45.7 | 16.70* | |||
| F1,184 | |||||||
| Age (years) | 12.5 | 2.4 | 12.1 | 2.5 | 12.5 | 2.6 | ns |
| Estimated full scale IQ | 97.4 | 10.8 | 100.3 | 11.5 | 105.7 | 11.5 | 10.2* |
| ADHD diagnosis | |||||||
| Inattentive (N) | – | 2 | – | ||||
| Hyperactive-impulsive (N) | – | – | – | ||||
| Combined (N) | 56 | 21 | – | ||||
| Anxiety disorder (N) | 28 | – | – | ||||
M mean; SD standard deviation; ADHD attention-deficit/hyperactivity disorder; DSM-IV Diagnostic and Statistical Manual for Mental Disorders (4th edition); ns non-significant
* P < 0.05; contrasts based on P-values of 0.05