Analyses revealed both within- and cross-substance overlap in non-shared environmental factors as well, but unlike the associations observed with genetic factors, the degree of overlap differed substantially between alcohol and cannabis. The rE for cannabis use and cannabis dependence symptoms was 0.889; for alcohol consumption and AD symptoms, rE = 0.546. The cross-substance correlations were also more modest than those observed with genetic factors. Non-shared environmental influences on alcohol consumption and cannabis use were correlated at rE = 0. 298, AD symptoms and cannabis dependence symptoms at rE = 0.246.
