more likely to be street drug users or to report problems with alcohol or drugs. The effects were strongest in those with comorbid drug and alcohol problems but there were no statistically significant effects in individuals with alcohol or nicotine dependence in the absence of illicit drug use. In contrast, when examining cannabis dependence alone (and not general substance dependence) Tyndale et al [68] found that A/A individuals were 0.25 times less likely to be cannabis dependent (but, potentially more likely to try cannabis). The authors argue that the reduced risk for cannabis dependence may stem from diminished FAAH activity leading to increased levels of endogenous cannabinoids which may ameliorate craving and withdrawal.
