The outline of the paper is as follows. First, we estimate the amount of variance in initiation of cannabis use explained collectively by the currently measured SNPs. The purpose of such analysis is to obtain an indication of the total signal in the measured (and tagged) SNPs without identifying individual SNPs. Second, we conduct SNP-based association analyses of initiation and age at onset. Our primary focus is on identifying genes tagged by the SNPs, relevant to our traits. Therefore, next, we incorporate these SNP-based results in two gene-based analyses. These analyses are exploratory, i.e., conducted genomewide.
