Our analyses of the shared genetic risk between OCD and other psychiatric disorders provides further insights into the etiology of OCD. In line with previous observations38,78, OCD was significantly genetically correlated with multiple psychiatric disorders and traits. The strongest genetic correlations were observed for anxiety disorders, depression and anorexia nervosa, all of which are highly comorbid with OCD79. This aligns with previous findings from cross-disorder analyses suggesting a shared genetic susceptibility among most psychiatric disorders38,80,81. A notable exception is our finding that risk variants for OCD are protective for alcohol dependence82, which is at odds with epidemiological evidence strongly linking OCD and alcohol-related disorders83 but in line with a recent paper79 reporting a lower-than-expected lifetime comorbidity of substance use disorders in OCD. The observed pattern of correlations with other phenotypes can be thought of as falling into two categories: compulsivity–impulsivity and rumination–worry–neuroticism. In both categories, the patterns of genetic correlations appear to follow a gradient across disorders and traits. For example, in the compulsivity–impulsivity category, strong positive correlations are seen with anorexia nervosa and Tourette syndrome, which are disorders with
