Risk Factors. Since the exact causes of schizophrenia are not known, it is difficult to identify risk factors. However, there are factors that appear to contribute to the likelihood of developing schizophrenia. These are: Family history of schizophrenia, Older age of father, Increased immune system activation, such as from autoimmune diseases, Exposure to malnutrition, toxins, or viruses in utero, particularly in the first and second trimesters.
