As a mother with a history of mental illness in the family, it's only natural to wonder why these illnesses develop. A lot of my beliefs are based on science/facts. I truly believe that we can prevent disease with knowledge, nutrition and nurturing. I may be neurotic about a lot of things but being pregnant places a lot of responsibility on the mother. When it comes to having a genetic link to mental illness is your family, you must make sure you are getting enough vitamin D, DHA and (on the horizon) choline. All beneficial to building a healthy fetal brain. You must also understand how environment plays a part in developing the illness. I think that a lot of the choices we make can trigger all sorts of outcomes. I encourage you to read this very interesting article about clues to preventing schizophrenia. Fascinating!