No, there is a large amount of factors that have been linked to being able to cause schizophrenia. There is no final answer to the debate at the moment.
"A particularly stable and replicable finding has been the association between living in an urban environment and the development of schizophrenia, even after factors such as drug use, ethnic group and size of social group have been controlled for.[142] A recent study of 4.4 million men and women in Sweden found a 68%–77% increased risk of diagnosed psychosis for people living in the most urbanized environments, a significant proportion of which is likely to be described as schizophrenia.
The effect does not appear to be due to a higher incidence of obstetric complications in urban environments.[144] The risk increases with the number of years and degree of urban living in childhood and adolescence, suggesting that constant, cumulative, or repeated exposures during upbringing occurring more frequently in urbanized areas are responsible for the association.
Various possible explanations for the effect have been judged unlikely based on the nature of the findings, including infectious causes or a generic stress effect. It is thought to interact with genetic dispositions and, since there appears to be nonrandom variation even across different neighborhoods, and an independent association with social isolation, it has been proposed that the degree of "social capital" (e.g. degree of mutual trust, bonding and safety in neighborhoods) can exert a developmental impact on children growing up in these environments."
So it does seem that it's inflictable, though we don't quite know by what. I can see that brainwashing may trigger it if someone was genetically predisposed to it. One theory may be that living in an urban environment is more of a trigger for those who are genetically predisposed to it. It seems like genetics is a requirement, though, suggesting it's not inflictable at will.
Yeah. We do sort of know why, it's just not exactly something that is easily proven or explicitly demonstrable through scientific method.
However, anyone who has gone through a bad breakup and gone a bit wacky has felt what emotional stress can do to the mind, you see it all the time seeing couples arguing and yelling psychotic things into the phone and slamming it, etc. It jams up the conscious process! Too much of this does cause schizophrenic states, and left unresolved can cause significant damage.
See also http://en.wikipedia.org/wiki/Causes_of_schizophrenia