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. Author manuscript; available in PMC: 2010 Mar 24.
Published in final edited form as: Addiction. 2009 Mar;104(3):420–429. doi: 10.1111/j.1360-0443.2008.02457.x

Table 4.

Standardized proportions of additive genetic (A), shared (C) and non-shared (E) environmental variance in Cannabis Use (CU) and Peer Group Deviance (PGD) including the proportions of variance in PGD which can be explained by CU as well as variance which is unique to PGD.

15–17 years 18–21 years 22–25 years

PGD CU PGD CU PGD CU

Total A variance (%)→ 25 33 28 32 25 54
 A Explained by CU 58% - 50% - 78% -
 A Unique to PGD 42% - 50% - 22% -
Total C variance (%) → 27 45 26 39 24 16
 C Explained by CU 73% - 66% - 25% -
 C Unique to PGD 27% - 34% - 75% -
Total E variance (%) → 47 22 46 28 51 30
 E Explained by CU 21% - 26% - 22% -
 E Unique to PGD 79% - 74% - 78% -

Results are based on the best fitting CU → PGD causal model path coefficients in Table 3 using Wright's (91) tracing rules.