Research has got to the point that researchers like Stephen Lawrie (University of Edinburgh) can predict who will get some major mental illnesses years before they develop. The overall accuracy of these predictions is about the same as in cancer screening. A key question now is: would you want to know if you, a child or parent was at high risk? Your answer might depend on how effective any treatment would be, the risk of false positive and false negative diagnoses, and the overall cost. Are there other factors?