The neurocognitive deficit in schizophrenia: a review of existing data

Background: During the recent years, the focus of research on schizophrenia was moved to the cognitive deficits whose nature is extremely complex. Methods: The authors performed a selective review of the literature and included in the current article the papers they considered important according to their experience. Results: Today it is clear that most components of attention, are affected. There is not a primary deficit in a specific component of attention, however patients are typically slow and their volitional drive varies. The patients discriminative ability is dramatically reduced in direct relationship to the increase of the size of the series. Research so far supports the presence of deficits in the explicit part of remote memory, while the implicit part remains unaffected. It seems that patients with dominant positive symptoms manifest better neurocognitive function; the literature suggests that neurocognitive symptoms group independently from the other symptoms of psycho- sis. They are also present already during the early stages, and possibly even before positive symptoms. The neurobiological substrate of this deficit includes disorders located at least in the anterior cingulate, and the cortico-cerebellar-thalamo-cortical circuit. Conclusions: The neurocognitive deficit in schizophrenia is still not well understood and is considered to be the most significant predictor of long term outcome and of the ability of the patient to return in the community