A prospective 2-year follow-up study of neurocognitive functioning in patients with first-episode schizophrenia

Abstract

To investigate the temporal stability, or progressivity, of neuropsychological (NP) impairment in schizophrenia, 50 patients with first episode (FE) schizophrenia and 50 healthy controls were given a battery of tests at the outset of the study and after a two-year interval. Both patient and control groups were balanced with respect to age, gender, education and parental socioeconomic status. Summary rating scales for semantic memory (SEM), visual memory (VIM), verbal learning (VBL), visual-motor processing and attention (VSM) and abstraction/flexibility (ABS) were constructed. FE schizophrenics showed improvement in VBL, stability of function in SEM, VSM and ABS and absence of improvement in VIM. While performance in VSM and VIM is influenced by medication status, SEM seems to be trait-related and stable; VBL, however, seems to be state-related. Our data suggest that there is no proof for the assumption of progressive deterioration in NP functioning during the first few years of illness.

A Longitudinal Analysis of Memory in Patients with Schizophrenia

“…Although Bilder et al (1991) reported that digit span and visual span declined over 12 months, these findings were not replicated in several other studies that also measured the same abilities (Addington et al, 1991;Heaton et al, 2001;Hoff et al, 1992;Rosmark et al, 1999;Rund & Landro, 1995;Rund et al, 1997;Sweeney et al, 1991). In addition, the finding by Albus et al (2002) that visual reproduction declined over a 24-month period is also not consistent with previous research (Gold et al 1999;Heaton et al 2001;Hoff et al, 1992;Nopopolous, 1994;Sweeney et al, 1991). Hence, as with the majority of previous studies, the current study accords with the notion that memory function is substantially impaired, but does not progressively deteriorate in schizophrenia; and may improve in some cases for some aspects of memory (principally verbal in this study).…”

“…Although a link between memory changes and medication has been reported (Albus et al, 2002;Rund et al, 1997;Sweeney et al, 1991), others have found no link (Censits et al, 1997;Nopoulus et al, 1994;Saykin et al, 1994) and the recent meta-analysis by Aleman et al (1999) indicates that medication dosage is not a moderator of memory function in schizophrenia. Another unresolved and related issue concerns any association between memory changes and psychotic symptoms.…”

“…Of those studies that have reported change, some have reported improvements in verbal memory (Addington, Addington & Maticka-Tyndale 1991;Albus et al, 2002;Bilder et al, 1991;Gold et al, 1999;Sweeney, Haas, Keilp & Long 1991), visual memory (Addington et al, 1991;Albus et al, 2002); and short term memory (Rund, Landro & Orbeck, 1997). Conversely, others have reported deteriorations in visual memory and short term memory (Albus et al, 2002;Bilder et al, 1991).…”

“…To address this, it is necessary to include a control sample to determine the degree of practice effect that may exist on tests. Examining the studies of memory in schizophrenia in Table 1, a minority (6/13) included controls (Albus et al, 2002;Censits, Ragland, Gur & Gur, 1997;Heaton et al, 2001;Rund, 1989;Rund and Landro, 1995;Rund et al, 1997). Given the normal impact of aging on memory, it is also necessary to match controls with the patients on such relevant variables.…”

Effects of Acute Ketamine Infusion on Visual Working Memory: Event-Related Potentials

“…Cognitive deficits, such as working memory (WM) impairment, are cardinal features of schizophrenia (1) that are present before the onset of psychosis and are independent of illness relapse (2)(3)(4). These deficits are more accurate predictors of poor social and occupational function than psychotic symptoms (5)(6)(7).…”