As demonstrated by the distribution of the four groups in Table 1, over the 30 years 41.3% (Groups 1 plus 3) of the 397 men met criteria for an AUD, while 20.6% (Groups 1 plus 2) fulfilled criteria for a SUD. The SUDs included 51.2% of the 397 men with a cannabis use disorder only, 25.6% with an amphetamine and/or cocaine diagnosis only, 14.6% with combined cannabis and stimulant diagnoses, and 8.5% with a SUD related to cannabis or stimulants combined with other drug conditions. Consistent with Hypothesis 1(the presence of one diagnosis will increase the risk for the other), in this prospective study of men at high risk for AUDs, the rate of a second substance-related diagnosis was almost two-fold higher among individuals who had either SUDs or AUDs. Thus, 62 of the 164 (37.8%) probands with an AUD in Groups 1 plus 3 also had a SUD, and 62 of the 82 (75.6%) men with a SUD in Groups 1 plus 2 also had an AUD.
