Obsessions and compulsions as a distinct cluster of symptoms in schizophrenia: a neuropsychological study.

Using neurocognitive testing, the present study assessed whether obsessions and compulsions could represent a distinct cluster of symptoms in schizophrenia. We formulated our hypothesis based on data from nonschizophrenic patients, expecting to find that schizophrenic patients with obsessive-compulsive (OC) symptoms would experience more difficulties in the same cognitive areas as nonschizophrenic patients with obsessive-compulsive disorder (OCD). Patients had separate psychiatric and cognitive evaluations. The OC and non-OC schizophrenic subjects did not differ significantly on the positive and negative symptom scores. However, compared with non-OC schizophrenic patients, those with OC symptoms performed worse on cognitive areas thought to be impaired (i.e., visual-spatial skills, delayed nonverbal memory, and cognitive shifting abilities). In addition, the severity of OC scores correlated with poor performance in these areas of cognition. Our results support our hypothesis, specifically that OC symptoms may constitute a distinct cluster separate from psychosis in schizophrenia and raise the possibility of a distinct subtype of schizophrenia. The theoretical and clinical implications of these findings are discussed.