Variation at FAAH C385A was not associated with most of the phenotypes assessed, including craving and most of the acute effects measures. However, C385A variance was associated with several intermediate phenotypes. As predicted, after marijuana abstinence, C/C individuals reported more severe withdrawal symptoms than A/A and A/C individuals. Furthermore, C/C individuals displayed an increase in happiness after smoking marijuana, compared to A/A and A/C individuals, whose happiness decreased. Together, these results suggest that C/C individuals experience more negative effects when they are abstinent and more positive effects after they smoke marijuana; these differences might make them more liable to progress to CD than A/A and A/C individuals.
