Obsessive compulsive symptoms in schizophrenia: Associations with neuropsychological function
Clinical experience and empirical observations suggest that the comorbidity of obsessive compulsive (OC) symptoms and schizophrenia is higher than would be expected by chance. Because research suggests that schizophrenia and obsessive-compulsive disorder (OCD) may result from similar disruptions in neurobiological circuitry, it is hypothesized that some shared and some unique pathophysiology between the two disorders could lead to the coexpression of what appear to be completely different symptoms in a single individual. In order to directly examine the clinical expression and indirectly examine the underlying pathophysiology of these two disorders, the present study compared three groups of individuals (people with schizophrenia with OC symptoms, people with schizophrenia without OC symptoms, and people with OCD) on neuropsychological functioning and symptom levels (both those associated with OCD and those associated with schizophrenia). It was predicted that performance on neuropsychological tests of frontal lobe functioning would differ between the three groups. Specifically, it was predicted that dorsolateral prefrontal dysfunction would be unique to schizophrenia and orbitofrontal dysfunction would be unique to OCD and schizophrenia with OC symptoms. It was proposed that people with schizophrenia and people with OCD share visual spatial dysfunction, visual memory impairments, and attentional impairments. In these shared areas of impairment, it was hypothesized that people with schizophrenia with OC symptoms will demonstrate greater levels of impairment than people with either schizophrenia or OCD alone due to the pathophysiological double jeopardy that these individuals may be experiencing. Although not significant at the designated alpha level, results of the study suggest that, rather than demonstrating a unique pattern of neuropsychological impairments as predicted, the group of individuals with schizophrenia and OC symptoms performed worse than the other two groups across almost all neuropsychological domains. Comorbidity of OC symptoms was not associated with increased positive symptoms or duration of schizophrenic illness. These results suggest that schizophrenia with OC symptoms may be a distinct subtype within the schizophrenia spectrum that is characterized by more severe general cognitive involvement but not more severe classic schizophrenic symptomatology.
Fastenau, Purdue University.
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