Previous studies have consistently documented that both AN and MDD are associated with a higher risk of SA [e.g., (Bolton et al., 2008; Bulik et al., 2008; Chesney et al., 2014; Forcano et al., 2011; Pisetsky et al., 2013)]. Furthermore, genetic factors are known to play a role in all three phenotypes [e.g., (Bulik et al., 2010; Hawton et al., 2012; Roy, Segal, & Sarchiapone, 1995)]. However, the heritability estimate for AN in this study was lower than that observed in prior reports; this is likely due to the broader AN definition used here (Dellava et al., 2011). Our observations that the comorbidity of AN and SA and of MDD and SA can be largely attributed to shared genetic factors are similar to those reported by Wade et al. (Wade et al., 2015) in a general population sample of twins. The authors found that eating disorders are associated with increased risk for suicidality and the comorbid pattern appeared to be almost entirely explained by shared genetic factors.
