The Relationship of Motivation and Neurocognition with Functionality in Schizophrenia: A Meta-analytic Review.

The role that neurocognition plays in functionality in schizophrenia has been widely examined, although in recent years increasing attention has been paid to the influence of motivation instead. This study provides a review of the relationship of neurocognition and motivation with functionality in schizophrenia, taking into account objective/subjective functionality assessment, demographic variables, and the different terms used when referring to motivation. A search of electronic databases identified 34 studies that met the inclusion criteria for review. Correlation coefficients between motivation and functionality and between neurocognition and functionality were extracted. For a better understanding, potential moderator variables were also extracted. Meta-analysis showed that both motivation and neurocognition assessments were strongly associated with functioning, with correlations between motivation and functional outcomes being stronger. However, more than three-quarters of the variance in outcome remained unexplained by the moderating factors examined. The paper concludes with recommendations for clinical practice and future research.

Trends in the Study of Motivation in Schizophrenia: A Bibliometric Analysis of Six Decades of Research (1956-2017).

Motivation in schizophrenia has been a key research aim for several decades. Motivation is a very complex process underlying negative symptoms that has been assessed and identified using very different instruments and terminologies. This study provides a comprehensive overview of the growing literature production and highlights an extensive set of variables to better understand the study of motivation. Electronic databases were searched in order to compile relevant studies of motivation in individuals with schizophrenia. The initial search identified 3,248 potentially interesting records, and of these, 161 articles published between 1956 and 2017 were finally included. Information such as year of publication, journal, country, and number of authors was codified. Variables related to sample characteristics, methodological aspects, and motivational terms were also extracted. The results revealed a significant growth trend in literature production, especially since the 2000s, with reward as the main term studied. In addition, questionnaires were identified as the preferred instrument to assess motivation in patients with schizophrenia. Other aspects such as country of publication, authors, journals of publication, and co-citation network analysis were also examined. The discussion offers recommendations for future research.

Neurodesarrollo o neurodegeneración: Revisión sobre las teorías de la esquizofrenia / Neurodevelopment or neurodegeneration: Review of theories of schizophrenia

La etiopatogenia de la esquizofrenia ha sido explicada por diversas teorías. La hipótesis del neurodesarrollo anormal se basa en la presencia de alteraciones tanto prenatales como perinatales, diferencias en el coeficiente intelectual, o la existencia de anormalidades genéticas, que al interaccionar con ciertos factores medioambientales, hacen que el trastorno esquizofrénico se manifieste en algún momento del desarrollo. Esta teoría es muy bien acogida por la comunidad científica ya que explica muy bien cómo estos factores dan como resultado una alteración en el desarrollo normal y como pueden derivar en un trastorno de esquizofrenia. Por otra parte, una cantidad menor aunque no menospreciable de estudios sugiere la existencia de un proceso degenerativo y se sustentan en variables como la presencia de neurotoxicidad en los cerebros de individuos con esquizofrenia, las alteraciones estructurales y de conectividad cerebral. En este contexto se revisan los diferentes factores subyacentes a ambas hipótesis, donde algunos son difíciles de catalogaren uno u otro enfoque dada la controversia y falta de consenso en los datos. Finalmente se discute la necesidad de adoptar un modelo alternativo no excluyente que ayude a comprender la evidencia disponible sobre el origen, curso y consecuencias de la enfermedad

Many hypothesis have tried to explain the aetiology of schizophrenia, the abnormal neurodevelopmental hypothesis is one of the most widely acknowledged and is based on the presence of both prenatal and perinatal disorders, differences in IQ or the existence of genetic abnormalities, which, with the interaction of certain environmental factors, schizophrenia could occur at some point in the development. This hypothesis provides a good account of how these factors result in an alteration in the normal development and how they can lead to a disorder of schizophrenia. On the other hand, a smaller but not insignificant number of studies based on variables such as the presence of neurotoxicity in the brains of individuals with schizophrenia, alterations at the structural and brain connectivity, suggest the existence of a degenerative process in the course of this disease. In this work, we review the different factors underlying both hypotheses, some of which are difficult to categorize in either approach given the controversy and lack of consensus in their interpretation of the available data. Finally, we discuss the need for a non-exclusive alternative model to help understand the available evidence on the origin, course and consequences of the disease

Neurodevelopment or neurodegeneration: review of theories of schizophrenia.

Many hypothesis have tried to explain the aetiology of schizophrenia, the abnormal neurodevelopmental hypothesis is one of the most widely acknowledged and is based on the presence of both prenatal and perinatal disorders, differences in IQ or the existence of genetic abnormalities, which, with the interaction of certain environmental factors, schizophrenia could occur at some point in the development. This hypothesis provides a good account of how these factors result in an alteration in the normal development and how they can lead to a disorder of schizophrenia. On the other hand, a smaller but not insignificant number of studies based on variables such as the presence of neurotoxicity in the brains of individuals with schizophrenia, alterations at the structural and brain connectivity, suggest the existence of a degenerative process in the course of this disease. In this work, we review the different factors underlying both hypotheses, some of which are difficult to categorize in either approach given the controversy and lack of consensus in their interpretation of the available data. Finally, we discuss the need for a non-exclusive alternative model to help understand the available evidence on the origin, course and consequences of the disease.