Obsessive-compulsive symptoms in schizophrenia

Schizophrenia and obsesive compulsive disorder (00) are among the oldest described psychiatric disorders. Although they appear to be two distinct psychiatric disorders, early literature about the existence of obsessive-compulsive symptoms in schizophrenia dates back to the 1920's. The findings that atypical antipsychotics exacerbate obsessive-compulsive symptoms among schizophrenic patients and the emergence of a possible biological relation between the two diseases increased interest in this subject. Until the 1990's information about the aetiology of obsessive-compulsive symptoms which are observed in about 60% of schizophrenic patients, was insufficient. Recently there has been progress in explaining the structural and functional abnormalities in both OCD and schizophrenia. Knowledge of the cortico-subcortical circuits might explain the co-incidence of symptomatology in the two disorders. It is shown that there is prefrontal cortex dysfunction in both disorders but the bases of dysfunctions are distinct from each other. These dyfunctions derive from two different neuro-anatomical systems partially connected with each other and with different neuro-anatomical connections. It is suggested that dorsolateral prefrontal cortex (DLPC) dysfunction occurs in schizophrenia and ventro-medial prefrontal cortex dysfunction (VMPC) in OCD. In this review, the incidence of obsessive-compulsive symptoms in schizophrenia, their effect on the disorder, the features of the schizo-obsessive patient group and the mechanism of how atypical antipsychotics exacerbate obsessive compulsive symptoms are discussed. Thus, we aimed to highlight the neurobiologic heterogeneity and phenomenology of schizophrenic disorder.