Table 2

 Comparison of demographic details of the VPT and term groups

VPT casesTerm controls
*For statistical comparison, social class was collapsed into two groups, higher (I and II) and lower (III–V and unclassified). χ2 (1,1) = 5.74; p = 0.017; †χ2 (1,1) = 0.892; p = 0.389; ‡χ2 (1,2) = 5.54; p = 0.063; ¶F = 16.17; df = 1,203; p<0.001; §F = 15.24; df = 1,204; p<0.001.
Parental social class
    I2023
    II4320
    III5021
    IV216
    V71
    Unclassified80*
Males/females78/7541/30†
Handedness,83.6/15.0./1.492.8/4.3/2.9‡
% right/left/mixed
Age at assessment in17.9 (0.67)18.5 (1.28)¶
years, mean (SD)
Full scale IQ,107.0 (15.3)116.4 (17.8)§
mean (SD)