A systematic review and narrative synthesis of data-driven studies in schizophrenia symptoms and cognitive deficits

Abstract

To tackle the phenotypic heterogeneity of schizophrenia, data-driven methods are often applied to identify subtypes of its symptoms and cognitive deficits. However, a systematic review on this topic is lacking. The objective of this review was to summarize the evidence obtained from longitudinal and cross-sectional data-driven studies in positive and negative symptoms and cognitive deficits in patients with schizophrenia spectrum disorders, their unaffected siblings and healthy controls or individuals from general population. Additionally, we aimed to highlight methodological gaps across studies and point out future directions to optimize the translatability of evidence from data-driven studies. A systematic review was performed through searching PsycINFO, PubMed, PsycTESTS, PsycARTICLES, SCOPUS, EMBASE and Web of Science electronic databases. Both longitudinal and cross-sectional studies published from 2008 to 2019, which reported at least two statistically derived clusters or trajectories were included. Two reviewers independently screened and extracted the data. In this review, 53 studies (19 longitudinal and 34 cross-sectional) that conducted among 17,822 patients, 8729 unaffected siblings and 5520 controls or general population were included. Most longitudinal studies found four trajectories that characterized by stability, progressive deterioration, relapsing and progressive amelioration of symptoms and cognitive function. Cross-sectional studies commonly identified three clusters with low, intermediate (mixed) and high psychotic symptoms and cognitive profiles. Moreover, identified subgroups were predicted by numerous genetic, sociodemographic and clinical factors. Our findings indicate that schizophrenia symptoms and cognitive deficits are heterogeneous, although methodological limitations across studies are observed. Identified clusters and trajectories along with their predictors may be used to base the implementation of personalized treatment and develop a risk prediction model for high-risk individuals with prodromal symptoms.

Assessing cognition in people with severe mental disorders in low- and middle-income countries: a systematic review of assessment measures

“…Research shows that people with SMDs have significantly more cognitive difficulties compared to healthy controls [3][4][5][6][7]. In support of this, a recent systematic review showed that cognitive symptoms in people with schizophrenia (PWS) had heterogenous trajectories [8].…”

Healthcare resource utilization and quality of life by cognitive impairment in patients with schizophrenia

“…Levels of neurocognitive impairment among patients with schizophrenia range, on average, up to 2 standard deviations (SDs) below healthy individuals ( Mesholam-Gately et al, 2009 ). Among patients with schizophrenia, level of cognitive impairment varies from near-normal to severe deficits ( Green et al, 2020 ; Habtewold et al, 2020 ). Cognitive impairment is persistent throughout life stages and changes in schizophrenia symptoms ( Keefe, 2014 ).…”

Symptom Monitoring based on Digital Data Collection During Inpatient Treatment of Schizophrenia Spectrum Disorders – a Feasibility Study

“…Forty percent of inpatients suffer from a relapse within one year even though they received appropriate therapy (Barnett et al, 2018) and each new episode increases the risk of chronicity (Alvarez-Jimenez et al, 2012). Hence, it has been suggested that detailed information on risk and symptom profiles might help to identify patients that are particularly vulnerable to relapse (Habtewold et al, 2020). The implementation of data collections during inpatient treatment for schizophrenia could help to quantify symptom development and treatment response.…”