The results of the sibling comparisons are shown in Table 3. Individuals with higher EduYears-GPS compared to their siblings had lower alcohol, nicotine, and cannabis criterion counts. Sibling differences in EduYears-GPS accounted for 0.17%, 0.20%, and 0.13% of the variance in AUDSX, NDSX, and CUDSX, respectively. There were also family-level effects, whereby those in sibling groups with higher EduYears-GPS-mean had lower alcohol, nicotine, and cannabis criterion counts. These family-level effects accounted for 0.29%, 1.89%, and 0.22% of the variance in AUDSX, NDSX, and CUDSX, respectively.
