Scientists now agree that the onset of psychosis is always involved multiple factors, none of which by itself is not enough. In the game, a certain propensity (disposition) for schizophrenia, which may or may not apply. This features is especially excessive sensitivity (to certain conditions) and, consequently, excessive mental vulnerability. The proportion of biological, psychological and social influences on the disease in each patient is different: someone dominated by biological causes (eg. A difficult birth), with another disappointing family background, with additional situational load (graduation, relationship etc.) Source: http://www.cureinnature.com/