For many years, the general belief in the medical and mental health community has been that psychosis is physically and genetically based and that the environment has no impact on its development.
In recent years, studies are showing that environmental trauma and adversity in the early years is connected with psychosis.
A paper just published in the journal Neuropsychiatry just strengthened support for this link. Four researchers (including Dr. Bruce Perry) performed a search for relevant papers published since 2001, finding 125. They then reviewed those articles, which support the "traumagenic neurodevelopmental model" of psychosis, specifically the concept that brain changes caused by trauma parallel brain patterns present in patients diagnosed with psychosis.
The paper presents an overview of the brain changes that are important in detail, as well as a list of important points to come out of this survey.
This paper is available for free online: The traumagenic neurodevelopmental model of psychosis revisited, John Read, Roar Fosse, Andrew Moskowitz, Bruce Perry, Neuropsychiatry, Feb 2014.