Genetic liability to SCZ has been linked to numerous other psychiatric conditions, including bipolar disorder, major depression, obsessive compulsive disorder, anorexia nervosa, posttraumatic stress disorder, alcohol dependence and attention deficit hyperactivity disorder (Anttila et al., 2016); however, a preponderance of these studies have calculated genetic correlations (SNP-rg). Nonetheless, studies employing the PRS approach find strong associations with a variety of psychiatric phenotypes. Of particular interest, SCZ-PRS successfully distinguish between clinical subtypes of Bipolar Disorder, with stronger associations with Bipolar I and schizoaffective forms (Charney et al., 2017). Substance use disorders have also been robustly linked to SCZ-PRS e.g., (Carey et al., 2016a). In particular, addressing the controversy regarding the role of cannabis use in the development of psychosis (Hall and Degenhardt, 2008), multiple studies have used SCZ-PRS to clearly demonstrate the role of shared genetic etiologies between these two phenotypes (e.g., R2=.47% for SCZ-PRS and ever using cannabis), thus challenging prior causal assertions and providing a new outlook on this relationship that was not possible to query with twin data (Power et al., 2014, Carey et al., 2016a, Verweij et
