Increasingly - it looks like Epigenetics are the key way that people develop schizophrenia:
Epigenetic signaling in schizophrenia.
Growing evidences suggest that epigenetic modifications in certain brain regions and neural circuits represent a key mechanism through which environmental factors interact with individual’s genetic constitution to affect risk of psychiatric conditions throughout life.
from this new research:
more details here:
Epigenetic clue to schizophrenia and bipolar disorder
TWIN studies have shown that people with schizophrenia and bipolar disorder have changes in gene activity caused by their environment. The finding provides the strongest evidence yet that such gene changes might cause the conditions.
Jonathan Mill at the Institute of Psychiatry, King’s College London, and colleagues scanned the genome of 22 pairs of identical twins - chosen because one twin in each pair was diagnosed with schizophrenia or bipolar disorder.
As expected, the twins had identical DNA. However, they showed significant differences in chemical “epigenetic” markings - changes that do not alter the sequence of DNA but leave chemical marks on genes that dictate how active they are. These changes were on genes that have been linked with bipolar disorder and schizophrenia.
Epigenetic mechanisms in schizophrenia