That's not true. There are dozens of candidate genes for Schizophrenia. None have been linked conclusively, probably because none of them are entirely respons

That's not true. There are dozens of candidate genes for Schizophrenia. None have been linked conclusively, probably because none of them are entirely responsible. I think the general agreement in the field is that genetic abnormalities are necessary but not sufficient to cause Schizophrenia. If you are going to crack, it's usually because you are genetically predisposed to it and in the right environment to trigger the disorder. Using Schizophrenia as an example, there are plenty of mid-20's males that are in stressful environments...but don't become schizophrenic. A minority of those males will have a genetic abnormality that predisposes them, and they start hearing voices.