Table 1. Subject demographics. Data expressed as mean ± standard deviation (range). There were no significant between-group differences in age (t (80) = 0.49, p = 0.63) or IQ (t (80) = − 0.30, p = 0.76)

Age (years)

13.1 ± 2.7

(7–17)

12.9 ± 2.5

(8–17)

IQ (WASI)

110.1 ± 15.4

(70–140)

110.9 ± 11.3

(79–132)

ADI-R reciprocal social interaction

17.7 ± 4.4 (10–26)

–

ADI-R communication

16.3 ± 3.8 (8–23)

–

ADI-R restricted, repetitive, stereotyped behaviour

5.5 ± 2.3 (2–11)

–

ADOS communication

3.7 ± 1.5 (1–6)

–

ADOS reciprocal social interaction

7.4 ± 2.7 (3–13)

–

ADOS imagination/creativity

0.9 ± 0.7 (0–2)

–

ADOS Stereotyped behaviours, restricted interests

1.5 ± 1.5 (0–6)

–