title: Psychosocial factors in the neurobiology of schizophrenia: a selective review.
abstract: OBJECTIVE
  Various forms of social adversity have been implicated in the development and emergence of psychosis. However, how and when these events exert their influences are not clear. In this paper, we attempt to examine these putative psychosocial factors and place them in a temporal context and propose a neurobiological mechanism linking these factors.
  
  
  METHODS
  Medline databases were searched between 1966 and 2007 followed by the cross-checking of references using the following keywords: psychosocial, stress, stressors, life events, psychological, combined with psychosis and schizophrenia.
  
  
  RESULTS
  While some findings are conflicting, there are a number of positive studies which suggest that factors like prenatal stress, urban birth and childhood trauma accentuate the vulnerability for schizophrenia and other psychoses while other factors like life events, migration particularly being a minority group, and high expressed emotions, which occur later in the vulnerable individual may move the individual towards the tipping point for psychosis.
  
  
  CONCLUSIONS
  Overall, there is evidence to implicate psychosocial factors in the pathophysiology of schizophrenia. These factors may act via a common pathway, which involves stress-induced dysregulation of the HPA axis and the dopaminergic systems. To establish the causal relationship of the various factors would require prospective studies that are adequately powered.
authors.affiliation: Department of Early Psychosis Intervention, Institute of Mental Health, Buangkok Green Medical Park, 10 Buangkok View, Singapore. Caroline_lim@imh.com.sg
authors.forename: Caroline
authors.initials: C
authors.lastname: Lim
authors.forename: Siow Ann
authors.initials: SA
authors.lastname: Chong
authors.forename: Richard  S E
authors.initials: R
authors.lastname: Keefe
mesh_terms: D006801:Humans; D009420:Nervous System / Q000503:physiopathology*; D011584:Psychology; D012559:Schizophrenia / Q000503:physiopathology*