Participant demographic characteristics
| Characteristic | Autism spectrum disorder* n = 118 | Typically developing controls* n = 122 | F / χ2 | p value |
|---|---|---|---|---|
| Age, yr | 13.11 ± 4.64 | 20.98 ± 9.70 | F = 63.27 | < 0.001 |
| Male, n (%) | 113 (95.8) | 75 (61.5) | χ2 = 41.6 | < 0.001 |
| Left-handedness, n (%) | 9 (7.6) | 5 (4.1) | χ2 = 1.36 | 0.24 |
| Verbal IQ | 100.8 ± 19.9 | 111.6 ± 10.9 | F = 28.51 | < 0.001 |
| Performance IQ | 99.7 ± 21.1 | 111.5 ± 13.3 | F = 26.99 | < 0.001 |
| Full-scale IQ | 100.1 ± 20.1 | 112.3 ± 11.7 | F = 33.31 | < 0.001 |
| Autism Diagnostic Interview–Revised* | ||||
| Most severe at 4 to 5 yr | ||||
| Social reciprocal interaction | 19.68 ± 6.98 | – | – | – |
| Communication: verbal | 14.68 ± 5.03 | – | – | – |
| Communication: nonverbal | 7.84 ± 3.43 | – | – | – |
| Repetitive or stereotyped behaviour or interests | 7.26 ± 2.67 | – | – | – |
| Current | ||||
| Social reciprocal interaction | 10.29 ± 4.71 | – | – | – |
| Repetitive or stereotyped behaviour or interests | 5.27 ± 2.52 | – | – | – |
| Social Responsiveness Scale† | ||||
| Social awareness deficits | 20.57 ± 5.29 | 12.50 ± 5.95 | F = 78.05 | < 0.001 |
| Social communication deficits | 40.04 ± 14.95 | 8.82 ± 7.09 | F = 208.91 | < 0.001 |
| Social emotion deficits | 12.81 ± 4.66 | 3.57 ± 3.52 | F = 161.74 | < 0.001 |
| Stereotyped behaviours | 20.28 ± 7.54 | 3.92 ± 4.31 | F = 216.78 | < 0.001 |
| Total score | 93.70 ± 28.74 | 28.80 ± 17.11 | F = 231.99 | < 0.001 |
↵* Values are mean ± standard deviation unless otherwise specified.
↵† The Autism Diagnostic Interview–Revised is an investigator-based interview of the caregiver, and the Social Responsiveness Scale is a caregiver-report measure of autistic traits in natural social settings. The subscores and total scores for both scales are shown here.