This study is amongst the first to use a genetically informative sample to look at the proposed inclusion of cannabis withdrawal in the upcoming DSM-5. We demonstrated that the proposed DSM-5 withdrawal criterion B is commonly experienced by lifetime cannabis users, and that withdrawal is moderately heritable. Furthermore, we found a very high correlation between cannabis withdrawal and abuse/dependence due to near-complete sharing of genetic influences and, to a lesser extent, unshared environmental influences on the two traits. This finding underscores the general cohesiveness of cannabis withdrawal with existing DSM-IV and upcoming DSM-5 definitions of cannabis use disorders and shows that a general genetic vulnerability to cannabis use disorder criteria, including withdrawal, may exist. By providing evidence for the shared genetic background with cannabis use disorders according to DSM-IV our findings add to the wealth of psychometric literature that recommends the addition of cannabis withdrawal to the definition of DSM-5 cannabis use disorder.
