Chunk #20 — 3. Results — 3.2 Familial Influences On and Overlap Between Childhood Maltreatment and Cannabis Phenotypes — 3.2.2. Covariation Between Maltreatment, Cannabis Initiation and Problems
Among EAs, C and E contributed to the association of maltreatment with cannabis initiation (rC=0.70; rE=0.25; see Table 4 and Figures 1a and 1b), but all covariation between maltreatment and cannabis problems was attributable to C (rC=0.74). The association between cannabis initiation and problems was attributable to shared environmental factors that were entirely overlapping with maltreatment (rC=0.52) and to genetic overlap (rA=0.84, equated across EAs and AAs) that was distinct from maltreatment, which was not itself heritable. In contrast, E explained all of the covariation of maltreatment with the two stages of cannabis involvement among the AAs (rE=0.36–0.39). After accounting for covariance with maltreatment, there was evidence for residual E that related cannabis initiation to problem use (rE=−0.55) as well as the cannabis-specific genetic association that was equated to the EAs (rA=0.84).
