title: The positive symptoms of acute schizophrenia and latent inhibition in humans and animals: underpinned by the same process(es)?
abstract: BACKGROUND
  It has been suggested that the positive symptoms of acute schizophrenia are a consequence of a disruption of the process that produces latent inhibition (slower acquisition of conditioned responding after preexposure to the conditioned stimulus) and that this effect can be modelled by pro- and antipsychotic compounds in healthy participants and in nonhuman animals. This idea assumes that latent inhibition in humans and animals is underpinned by the same process(es).
  
  
  METHODS
  First, we question the equivalence of human and animal latent inhibition. Second, we review the studies that have examined latent inhibition in populations with schizophrenia and in healthy populations after administration of amphetamine or haloperidol.
  
  
  RESULTS
  Theoretical analysis of the similarities and differences in latent inhibition effects, and the procedures used to generate them, in humans and animals renders the suggested equivalence between them unconvincing. The studies examining latent inhibition in populations with schizophrenia and in healthy populations after administration of amphetamine or haloperidol are marked by a number of methodological shortcomings and reveal discrepant results.
  
  
  CONCLUSIONS
  The theoretical and empirical analyses provide little support for a common process underlying deficits of latent inhibition in patients exhibiting positive symptoms of acute schizophrenia, and such deficits in experimental models in healthy humans and infrahumans.
authors.affiliation: School of Psychology, Cardiff University, Cardiff, UK. schmidthansenm1@cardiff.ac.uk
authors.forename: Mia
authors.initials: M
authors.lastname: Schmidt-Hansen
authors.forename: Mike
authors.initials: M
authors.lastname: Le Pelley
mesh_terms: D000661:Amphetamine / Q000494:pharmacology; D000818:Animals; D014150:Antipsychotic Agents / Q000494:pharmacology / Q000627:therapeutic use; D001522:Behavior, Animal / Q000187:drug effects; D003213:Conditioning, Psychological / Q000187:drug effects; D004195:Disease Models, Animal; D006220:Haloperidol / Q000494:pharmacology / Q000627:therapeutic use; D006801:Humans; D007266:Inhibition, Psychological; D012559:Schizophrenia / Q000188:drug therapy / Q000503:physiopathology*; D012565:Schizophrenic Psychology
chemical_list: D014150:Antipsychotic Agents; D000661:Amphetamine; D006220:Haloperidol