Across five substances (Fig. 1), withdrawal (3.4–12.8%) and time using (2.6–22.2%) were among the least prevalent symptoms among substance users; taking large amounts (10.5–45.8%) and inability to cut down (14.8–37.6%) were comparatively prevalent. Hallucinogens and inhalants were dropped from further analysis because of low prevalence. CFI, TLI, RMSEA, and the ratio of the first to the second eigenvalues from factor analyses (Table 3) indicated one dependence factor for each substance examined (factor loadings: alcohol, 0.76–0.95; amphetamines, 0.76–0.93; cannabis, 0.54– 0.96; cocaine, 0.75–0.93; sedatives, 0.75–0.93). Withdrawal had the lowest value of factor loadings (0.54) for cannabis dependence.
