While there is a lot of evidence that schizophrenia runs in families, it seems that the genetics are complicated because there is also a strong effect from environmental stressors like exposures by fetuses to certain viruses.
We all have vulnerable areas of our physiology due to our genetic makeup. The key is to work with the factors we can control, such as diet, nutrition, and exercise. The entire field of epigenetics studies how we can compensate for these genetic tendencies in order to avoid the development of disease.
For now, the formulation of epigenetic-based treatments is still in its infancy.