Cognitive control and impulsivity in deficit schizophrenia: neuropsychological and clinical characteristics

Over the years, various concepts concerning the nature of schizophrenia have emerged. One of the proposals put forward in the literature is the division of schizophrenia into its deficit and non-deficit subtypes. Compared to its non-deficit counterpart, the deficit type involves more severe cognitive dysfunctions. Among these, some authors enlist poorer cognitive inhibition and greater impulsivity, although their behavioral correlates still remain unclear. Structural and functional studies of the brain suggest the presence of links between impulsivity and inhibition in schizophrenia, but few studies to date have analyzed cognitive performance within these two domains in patients with the deficit type. In addition, little is known about the effectiveness of neurorehabilitation in reducing cognitive deficits in deficit schizophrenia. Thus, numerous questions in this area seem to warrant further research. In this paper we present clinical and neurobiological correlates of cognitive control and impulsivity against neuropsychological and psychopathological symptomatology of schizophrenia. In addition, we describe selected neuropsychological tools used in the diagnosis thereof. We touch upon potential benefits of cognitive rehabilitation in patients with schizophrenia, especially in terms of self-control. Last but not least, this paper presents an overview of previous research and an attempt to embed them in modern theoretical models of cognitive inhibition and impulsivity, for a better understanding of the nature of cognitive dysfunction in schizophrenia seems crucial for proper diagnosis and assessment of treatment effects, and in a broader context is important for understanding its effects on quality of life and functioning of patients and their families.