In a recent article on genetic counseling in psychiatry, Christine Finn, MD, and Jordan W. Smoller, MD, ScD, noted that family and twin studies have documented the familiality and heritability of schizophrenia, bipolar disorder, major depression, anxiety disorders, autism, attention-deficit/hyper- activity disorder (ADHD), and Tourette syndrome, among others, and that molecular genetic studies have begun to identify possible susceptibility loci for several of these disorders, most notably schizophrenia.