Table 1.
Characteristics of the non-diagnosed and clinically diagnosed children (means and SD unless otherwise stated)
| Characteristica | Non-diagnosedb | Diagnosed in the NPR | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Overall (n = 19,154) | Males (n = 9563) | Females (n = 9591) | P | Cohen’s d | Overall (n = 650) | Males (n = 466) | Females (n = 184) | P | Cohen’s d | |
| Total ADHD | 1.85 (2.77) | 2.19 (3.02) | 1.50 (2.45) | <.001 | 0.25 | 8.44 (5.53) | 8.72 (5.46) | 7.75 (5.64) | .08 | 0.18 |
| Inattention | 0.94 (1.58) | 1.13 (1.72) | 0.74 (1.41) | <.001 | 0.25 | 4.43 (2.86) | 4.60 (2.80) | 4.01 (2.97) | .03 | 0.21 |
| Hyperactivity/impulsivity | 0.91 (1.53) | 1.06 (1.67) | 0.76 (1.37) | <.001 | 0.20 | 4.02 (3.17) | 4.12 (3.17) | 3.76 (3.18) | .25 | 0.11 |
| Conduct | 0.08 (0.31) | 0.10 (0.35) | 0.07 (0.27) | <.001 | 0.10 | 0.60 (0.99) | 0.58 (0.97) | 0.63 (1.03) | .50 | − 0.05 |
| Learning | 0.25 (0.57) | 0.27 (0.59) | 0.23 (0.55) | <.001 | 0.07 | 1.01 (1.05) | 0.98 (1.02) | 1.11 (1.13) | .17 | − 0.12 |
| Medication % (n) | – | – | – | – | – | 552 | 84.98% (396) | 84.78% (156) | .93 | – |
Bold data signify statistical significance of the tests
All models were adjusted for familial clustering, year of birth, and SES
ADHD attention-deficit/hyperactivity disorder, NPR National Patient Register
aData were missing on some variables; all available data were used in analysis
bScores for the entire population can be found in the Supplementary Table 1