The magnitude and variability of neurocognitive performance in first-episode psychosis: a systematic review and meta-analysis of longitudinal studies

Abstract

Neurocognitive deficits are a core feature of psychotic disorders, but it is unclear whether they affect all individuals uniformly. The aim of this systematic review and meta-analysis was to synthesize the evidence on the magnitude, progression, and variability of neurocognitive functioning in individuals with first-episode psychosis (FEP). A multistep literature search was conducted in several databases up to November 1, 2022. Original studies reporting on neurocognitive functioning in FEP were included. The researchers extracted the data and clustered the neurocognitive tasks according to the seven Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) domains and six additional domains. Random-effect model meta-analyses, assessment of publication biases and study quality, and meta-regressions were conducted. The primary effect size reported was Hedges g of (1) neurocognitive functioning in individuals at FEP measuring differences with healthy control (HC) individuals or (2) evolution of neurocognitive impairment across study follow-up intervals. Of 30,384 studies screened, 54 were included, comprising 3,925 FEP individuals and 1,285 HC individuals. Variability analyses indicated greater variability in FEP compared to HC at baseline and follow-up. We found better neurocognitive performance in the HC group at baseline and follow-up but no differences in longitudinal neurocognitive changes between groups. Across the 13 domains, individuals with FEP showed improvement from baseline in all studied domains, except for visual memory. Metaregressions showed some differences in several of the studied domains. The findings suggest that individuals with FEP have marked cognitive impairment, but there is greater variability in cognitive functioning in patients than in HC. This suggests that subgroups of individuals suffer severe disease-related cognitive impairments, whereas others may be much less affected. While these impairments seem stable in the medium term, certain indicators may suggest potential further decline in the long term for a specific subgroup of individuals, although more research is needed to clarify this. Overall, this study highlights the need for tailored neurocognitive interventions for individuals with FEP based on their specific deficits and progression.

Longitudinal course of inflammatory-cognitive subgroups across first treatment severe mental illness and healthy controls

“…As shown in previous studies with overlapping samples (Demmo et al, 2017; Engen et al, 2019; Flaaten et al, 2023b, 2023a, 2022; Haatveit et al, 2015), our analyses comparing diagnostic status show domain-specific stability or improvement in cognitive functioning from baseline to follow-up. This is in line with longitudinal findings in SMI from other groups (Bora and Özerdem, 2017; Catalan et al, 2024; Torgalsbøen et al, 2023). A similar course of improvement in both SMI and HC may indicate practice effects, which is known for some of the cognitive tests used in this study (Beglinger et al, 2005).…”

“…For instance, cognitive subgroups with severe impairment typically have more symptoms and lower functioning (Miskowiak et al, 2023; Vaskinn et al, 2020), brain abnormalities as assessed by magnetic resonance imaging (de Zwarte et al, 2020; Wenzel et al, 2023, 2021; Wolfers et al, 2018; Woodward and Heckers, 2015), and higher levels of systemic inflammation (Pan et al, 2020, Watson et al, 2023). Evidence further suggests that cognitive functioning remains relatively stable throughout the illness course in both SZ and BD (Bora and Özerdem, 2017; Catalan et al, 2024; Ehrlich et al, 2022; Flaaten et al, 2022, 2023a, 2023b). Developing successful personalized treatments is contingent on increasing our understanding of the causes and maintenance of cognitive impairment in SMI.…”

“…Cognitive impairment is a central feature of severe mental illnesses (SMI), such as schizophrenia (SZ) and bipolar (BD) spectrum disorders (McCleery and Nuechterlein, 2019; Stainton et al, 2023). While highly prevalent, there is considerable heterogeneity in cognitive symptoms, ranging from mild to severe (Catalan et al, 2024; Haatveit et al, 2023; Lee et al, 2024; Van Rheenen et al, 2017; Wenzel et al, 2023). Numerous studies have identified transdiagnostic cognitive subgroups that are associated with different neurobiological characteristics, as well as clinical- and functional outcomes (Bora et al, 2023; Cowman et al, 2021; Lewandowski, 2020; Vaskinn et al, 2020; Wenzel et al, 2021).…”