Which of the following areas are associated with the cognitive deficits present in schizophrenia?

Cognitive deficits are accepted as a core feature in schizophrenia spectrum disorders that exist early in the course of the illness (Bilder et al., 2000), and that show greater severity than in other psychotic illnesses (Reichenberg et al., 2009). Moreover, cognitive dysfunctions are among the most critical determinants of functionality in schizophrenia (Green, 2006). Whether these cognitive deficits are static or change across the patient's lifespan is still under debate. Different studies examining the course of cognitive deficits during the first 2 years following onset of the illness reported stability or an improvement in most of the cognitive functions (Addington et al., 2005, Rodríguez-Sánchez et al., 2008, Crespo-Facorro et al., 2009, Becker et al., 2010). Furthermore, studies that address the evolution of general IQ have found changes similar to those observed in the controls (Leeson et al., 2011).

On the contrary, studies reporting lengthy follow-up intervals have observed poorer improvements in cognitive functions of the patients over time, when compared to the healthy controls (Hoff et al., 2005, Albus et al., 2006). These latter findings seem to support the results of previous studies showing a progressive cognitive deterioration in chronic schizophrenia patients (Waddington and Youssef, 1996, Harvey et al., 1999, Morrison et al., 2006). Moreover, some evidence has also suggested that the conclusions of raw improvements in cognition might be associated with symptomatic improvements (Mayoral et al., 2008).

Given these discrepancies, the distinctive trajectories of changes among the different cognitive functions during the patient's lifespan have been postulated in schizophrenia (Kurtz, 2005). That is, whereas cognition might be stable in younger patients, it seems to deteriorate among the elder patients.

Additionally, several previous studies observed stability in particular cognitive functions and a clear deterioration in some other cognitive domains. Thus, Stirling et al. (2003) who explored the first episode patients and Morrison et al. (2006) who analyzed individuals with chronic disease, have found a specific deterioration of visuospatial functions. A deteriorating course of verbal memory has also been reviewed in a recent article (Bozikas and Andreou, 2011).

On the other hand, cognition has shown a consistent relationship with disability and occupational outcome (Nuechterlein et al., 2011). This suggests that its course might have implications in these areas.

The purpose of this study was to investigate the long-term (3 years) course of cognitive deficits in a large and representative cohort of patients with a first psychotic episode of schizophrenia spectrum, and to evaluate its relationship with disability. A healthy control sample was also included in the study for the sake of comparison. Additionally, we sought to study the relationships between the course of cognitive function and other clinical and functional variables.

We hypothesized that no differences would be observed in the course of most of the cognitive functions between the patients and the controls, and that the subgroup of patients who might show a cognitive decline across time would also present with a worse clinical and functional outcome.

Study setting

The data for the present investigation was obtained from an on-going epidemiological and 3-year longitudinal intervention program of first episode psychosis (PAFIP) conducted at the outpatient clinic and the inpatient unit at the Marqués de Valdecilla University Hospital, Spain (Pelayo-Terán et al., 2008). Referrals to the PAFIP came from the inpatient unit and the emergency room at the Marqués de Valdecilla University Hospital, from community mental health services and other community health

Demographic and clinical characteristics

The comparison between patients and healthy subjects with respect to sociodemographic, clinical and cognitive characteristics is presented in Table 1. Patients and controls did not differ significantly in premorbid IQ (estimated by means of the WAIS III Vocabulary subtest) of age, years of education, or gender distribution (see Table 1). In addition, the subsamples of patients and controls that were selected for the ANOVAs, which were performed on every single cognitive factor did not

Discussion

The current study shows that patients are outperformed by controls at any time point in virtually all cognitive functions. The two groups increased their performance in all cognitive functions across time. Patients and controls increased their performance in the same proportion in all cognitive functions except for verbal and visual memory. Additionally, the subgroup of patients who had cognitive decline also achieved a lesser amelioration of negative symptoms and showed a worse functionality

Role of funding source

The present study was carried out at the Hospital Marqués de Valdecilla, University of Cantabria, Santander, Spain, under the following grant support: Instituto de Salud Carlos III PI020499, PI050427, PI060507, Plan Nacional de Drogas Research Grant 2005- Orden sco/3246/2004, SENY Fundació Research Grant CI 2005-0308007 and Fundación Marqués de Valdecilla API07/011.

No pharmaceutical company supplied any financial support towards it. The study, designed and directed by B C-F and JL V-B,

Contributors

José Manuel Rodríguez-Sánchez wrote the main body of the manuscript.

Rosa Ayesa-Arriola helped with the compilation of data and making of the tables and figures.

Rocío Pérez-Iglesias helped in the interpretation of result.

José Antonio Periañez performed statistical analyses.

Obdulia Martinez-Garcia and Elsa Gomez-Ruiz contributed with the compilation of data and recruitment of subjects.

Rafael Tabares-Seisdedos and Benedicto Crespo-Facorro gave overall supervision of the study.

Conflict of interests

Prof. Crespo-Facorro has received honoraria for his participation as a speaker at educational events from Pfizer, Bristol-Myers Squibb, and Johnson & Johnson. He has also received honorarium for participating in advisory boards from Eli-Lilly.

Dr. Perez-Iglesias has received support to attend conferences from Eli-Lilly.

Prof. Tabarés-Seisdedos has received grants from or acted as a consultant for the following companies: AstraZeneca, Janssen, Eli- Lilly, Lundbeck, Novartis, Pfizer, Sanofi-Aventis

Acknowledgment

We wish to thank the PAFIP researchers who helped with data collection and specially acknowledge Mrs. Gema Pardo and Noemi De la Fuente. Finally, we should also like to thank the participants and their families for enrolling in this study.

Cited by (30)

Recommended articles (6)