title: Neurobiology confirms psychopathology. On the antagonism of psychosis and obsessive-compulsive syndromes.
abstract: BACKGROUND
  Psychopathological concepts of the 19th and early 20th century postulated an antagonism between psychotic and obsessive-compulsive disorders, assuming obsessions and compulsions to have protective effects on psychotic disintegration. Although both disorders have been subject to intense multimodal research, their pathogeneses are yet to be fully understood.
  
  
  METHODS
  Here, we discuss recent neurobiological findings pointing towards opposite directions which are strongly reminiscent of the historical psychopathological antagonism.
  
  
  RESULTS
  Obsessive-compulsive syndromes (OCS) are efficiently treated with serotonergic substances, while on the other hand modern antipsychotic drugs exert antiserotonergic effects. Especially these atypical antipsychotic substances, however, were found to involve the risk of inducing second-onset OCS. Dopamine antagonists are potent antipsychotic substances, whereas the partial dopamine agonist aripiprazole has been associated with an antiobsessive potency. Within the glutamatergic system, reduced NMDA-dependent glutamatergic neurotransmission is discussed to be one major pathomechanism of psychotic disorders, whilst NMDA antagonists have proven to be effective in improving treatment-resistant OCS. While neurogenetic findings seem to separate the populations in heterogeneous samples, detailed neuroimaging studies suggest that both disorders affect similar neurocircuits in different manners.
  
  
  CONCLUSIONS
  With regard to these findings, future research on schizo-obsessive syndromes will have to be multimodal, integrating psychopathology, neuropsychology, functional imaging, neurogenetics and psychopharmacology. Prospective trials involving these methods might be able to elucidate the dysbalances of neurotransmission and to locate the neuroanatomical and neuropsychological correlates. In particular, this might contribute to defining schizophrenic patients at risk for developing second-onset OCS and to evaluating new treatment strategies in patients suffering from both psychosis and OCS.
authors.affiliation: Central Institute of Mental Health, Department of Psychiatryand Psychotherapy, University of Heidelberg, Mannheim, Germany. mathias.zink@zi-mannheim.de
authors.forename: Mathias
authors.initials: M
authors.lastname: Zink
authors.forename: Susanne
authors.initials: S
authors.lastname: Englisch
authors.forename: Harald
authors.initials: H
authors.lastname: Dressing
mesh_terms: D001921:Brain / Q000503:physiopathology*; D003937:Diagnosis, Differential; D006801:Humans; D009771:Obsessive-Compulsive Disorder / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology*; D011618:Psychotic Disorders / Q000175:diagnosis / Q000523:psychology*