Table 2. Characteristics of Individuals With ADHD Who Did and Did Not Take Medication During the Study Follow-up Period.
| Characteristic | ADHD Groupa | P Value for Test of Group Differencesb | |
|---|---|---|---|
| Medicated (n = 2745) |
Never Medicated (n = 973) |
||
| Male, No. (%) | 1386 (50.49) | 547 (56.22) | .002 |
| No. of tests per person | 1.58 (1.08) | 1.53 (0.89) | .18 |
| Age at test, y | 22.26 (3.36) | 21.63 (3.08) | <.001 |
| Test score | 94.12 (46.13) | 83.46 (45.32) | <.001 |
| IQ in stanine scoresc | 5.69 (1.86) | 5.41 (1.71) | .08 |
| Highest educational level >12 y of education, No. (%) | |||
| Father | 1262 (45.97) | 405 (41.62) | .02 |
| Mother | 1457 (53.08) | 464 (47.69) | .005 |
Abbreviation: ADHD, attention-deficit/hyperactivity disorder.
a
Data are presented as mean (SD) unless otherwise indicated.
b
Two-sided t tests were used for continuous variables. χ2 Tests were used for 2 × 2 contingency table with Yates correction.
c
Based on 20% nonmissing IQ data in males.