August 17, 2015
The first of many studies identified five major mental illnesses that could be traced to the same gene variations. Schizophrenia, bipolar disorder, depression, attention deficit hyperactivity disorder (ADHD) and autism all share variations on four chromosomes. Genome wide association studies (GWAS) were able to determine that these genetic variations explained between 17 – 28% of the risk of getting any of these illnesses. On the other hand, twin studies showed 81 percent heritability in schizophrenia. Clearly, a lot more is going on biologically than we know about.