Unadjusted, cannabis use in adolescence was associated with increased hazard ratios of future DP in all groups (Table 2). The hazard ratios increased in a graded manner, i.e., the more frequent cannabis use in adolescence, the higher was also the hazard ratio of future DP. When adjusted for covariates, the associations were attenuated; especially when adjusting for health behavioral factors in the groups reporting cannabis use 50 times or less. However, when all covariates where entered simultaneously,

the increased hazard ratio of DP remained statistically significant only in the group receiving late DP and reporting cannabis use more than 50 times. We found that having used cannabis more than 50 times in adolescence increased the risk for future DP. The increased risks remained to some extent when adjusted for social background, mental function and health behaviors, although they were substantially selleck inhibitor attenuated. The associations were only statistically significant for individuals receiving late DP. Among those receiving http://www.selleckchem.com/products/Vorinostat-saha.html DP in Sweden the great majority is 40 years or older and in our cohort they comprised 84%. This is to the best of our knowledge, the first study reporting the association between cannabis use in adolescence and risk of future DP. Our results are partially in line with previous research, reporting

cannabis use to be associated with exclusion from the labor market. Cannabis users have been found less likely to be in work (Davstad et al., 2013). It has been reported that frequent cannabis users are at increased risk for receiving social welfare assistance; they have been observed to have longer periods of receiving social welfare assistance than others and are also less likely to leave the welfare assistance system (Pedersen, 2011). Furthermore, cannabis use and problematic cannabis use have been found to be strongly associated with low occupational grade and unstable employment, as well as low work achievement and unemployment (Brook et al., 2011, Fergusson and Boden, 2008 and Redonnet et al., 2012). There is one possibility that the associations we

observed between high cannabis consumption and DP are actually non-causal, and exist due to factors associated with both the use of drugs and DP. Although we were able to control for a large number of factors previously associated STK38 with cannabis use and DP, there is always the possibility that the associations found are explained by other factors. It may also be the case that adolescent cannabis use may lead to a series of negative life events, such as for example subsequent illicit drug use, illness (e.g., dependence) and associated DPs. Prior studies have shown that frequent cannabis use increases the risk of illicit drug use uptake (Smith et al., 2011 and Swift et al., 2011). Among those who develop dependence on an illicit drug by age 25, in most cases this dependence involved cannabis (Boden et al., 2006).