As summarized in Table 1, Model 2 provided the best fit to the data to the symptom and diagnostic data. This is shown in Figure 4 which includes the standardized path coefficients and 95% confidence intervals. As summarized in Table 2, most of the genetic (97%) and non-shared environmental variance (97%) in initiation is unique to this measure, whereas almost all of its shared environment variance (96%) is explained by cannabis availability. Variation in the abuse phenotype comes from several sources. Approximately two thirds of the genetic variance (62%) comes from initiation while just over one third (36%) is unique to it. Almost all of the shared environmental variation (92%) in the symptoms can be explained by shared environmental effects for cannabis availability. Most (82%) of the non-shared environmental variance in abuse symptoms is associated with cannabis initiation, whereas only a small proportion (16%) is unique.
