affect [18]–[20], endophenotypes known to be involved in addiction vulnerability. As such, we focused a priori on whether individual genetic differences of the DRD2 and PENK genes associate with cannabis dependence and explored the possible mediation or moderation of intermediate endophenotypes in the genetic associations. Given the current lack of information as to the functional relevance of the PENK SNPs, we also assessed potential genotype relationships to mRNA expression levels in the postmortem human brain from another population sample.
