In the largest-ever study of its kind, published in the journal Cell, researchers identified more than 100 genetic variants that affect the risk for more than one mental health condition...Certain disorders shared many variants, allowing the researchers to divide the conditions into three groups of genetically-related conditions: disorders characterized by compulsive behaviors (anorexia nervosa, obsessive-compulsive disorder and, to a lesser extent, Tourette syndrome); mood and psychotic disorders (bipolar disorder, major depression and schizophrenia); and early-onset neurodevelopmental disorders (autism spectrum disorder, ADHD and Tourette syndrome).