from small sample sizes and a need for more advanced technological and statistical methodologies (McCarthy et al., 2008). Recent progress in all three areas, coupled with systems and network approaches, meta-analyses, and incorporation of both rare variants and additional structural and functional genetic information in analyses has shown promising results for psychaitric disorders including autism spectrum disorders and schizophrenia (Geschwind and Flint, 2015). However, most published GWAS findings continue to account for only a small portion of the variance for substance use outcomes (e.g., Hart and Kranzler, 2015).
