Table 6 shows the associations between the extent of cannabis use, assessed using a three-level variable distinguishing nonusers from lifetime users who either did or did not meet criteria for a diagnosis of cannabis abuse or dependence. Several features of the results displayed in this table are noteworthy: (a) there were particularly strong associations between cannabis involvement and other measures of substance involvement including dependence on the licit drugs (tobacco, alcohol) and illicit drug abuse/dependence. Similarly, there were consistent albeit less strong associations between cannabis involvement and measures of both externalizing behaviors (including a history of childhood conduct disorder, attention defict hyperactivity disorder (ADHD), and problem gambling) and internalizing behaviors (MDD, suicidal behaviors, anxiety disorders). In all comparisons those who met criteria for cannabis abuse or dependence had the highest risks of these disorders and nonusers had the lowest levels while individuals who reported having used cannabis but who did meet criteria for cannabis abuse/dependence having rates of these outcomes that were intermediate between these extremes.
