Table 1. Characteristics of Individuals With ADHD and Matched Population Control Individuals Who Had Taken the SweSAT.
Characteristic | Groupa | P Value for Test of Group Differencesc | |
---|---|---|---|
Patients With ADHD (n = 3718) |
Matched Controls (n = 8371)b |
||
No. of tests per person | 1.58 (1.09) | 1.74 (1.20) | <.001 |
Age at test, y | 22.10 (3.30) | 20.55 (2.44) | <.001 |
Test score | 91.40 (46.16) | 90.51 (43.02) | .20 |
IQ in stanine scoresd | 5.62 (1.82) | 5.86 (1.74) | .002 |
Highest educational level >12 y of education, No. (%) | |||
Father | 1667 (44.84) | 3851 (46.00) | .29 |
Mother | 1921 (51.67) | 4320 (51.61) | .60 |
Abbreviations: ADHD, attention-deficit/hyperactivity disorder; SweSAT, Swedish Scholastic Aptitude Test.
Data are presented as mean (SD) unless otherwise indicated.
Population controls were matched with each patient with ADHD on sex, birth year, and residential area at the time of diagnosis at a ratio of 10:1. A total of 8371 individuals from 37 180 matched controls had taken the test during the study follow-up.
Two-sided t tests were used for continuous variables. χ2 Tests were used for 2 × 2 contingency table with Yates correction.
Based on 20% nonmissing IQ data in males.