Examining the variability of neurocognitive functioning in individuals at clinical high risk for psychosis: a meta-analysis

Abstract

This study aims to meta-analytically characterize the presence and magnitude of within-group variability across neurocognitive functioning in young people at Clinical High-Risk for psychosis (CHR-P) and comparison groups. Multistep, PRISMA/MOOSE-compliant systematic review (PROSPERO-CRD42020192826) of the Web of Science database, Cochrane Central Register of Reviews and Ovid/PsycINFO and trial registries up to July 1, 2020. The risk of bias was assessed using a modified version of the NOS for cohort and cross-sectional studies. Original studies reporting neurocognitive functioning in individuals at CHR-P compared to healthy controls (HC) or first-episode psychosis (FEP) patients were included. The primary outcome was the random-effect meta-analytic variability ratios (VR). Secondary outcomes included the coefficient of variation ratios (CVR). Seventy-eight studies were included, relating to 5162 CHR-P individuals, 2865 HC and 486 FEP. The CHR-P group demonstrated higher variability compared to HC (in descending order of magnitude) in visual memory (VR: 1.41, 95% CI 1.02–1.94), executive functioning (VR: 1.31, 95% CI 1.18–1.45), verbal learning (VR: 1.29, 95% CI 1.15–1.45), premorbid IQ (VR: 1.27, 95% CI 1.09–1.49), processing speed (VR: 1.26, 95% CI 1.07–1.48), visual learning (VR: 1.20, 95% CI 1.07–1.34), and reasoning and problem solving (VR: 1.17, 95% CI 1.03–1.34). In the CVR analyses the variability in CHR-P population remains in the previous neurocognitive domains and emerged in attention/vigilance, working memory, social cognition, and visuospatial ability. The CHR-P group transitioning to psychosis showed greater VR in executive functioning compared to those not developing psychosis and compared to FEP groups. Clinical high risk for psychosis subjects shows increased variability in neurocognitive performance compared to HC. The main limitation of this study is the validity of the VR and CVR as an index of variability which has received debate. This finding should be explored by further individual-participant data research and support precision medicine approaches.

A randomized controlled trial of Goal Management Training for executive functioning in schizophrenia spectrum disorders or psychosis risk syndromes

“…GMT is a valuable addition to early intervention in the schizophrenia spectrum disorders and psychosis risk syndromes, because EF is important in everyday situations and frequently severely impaired in these patient groups [5,7,8]. Aside from the associations subjective EF has with personal recovery, experiencing that you are better able to plan, start and organize everyday tasks, monitor yourself and shift focus when required, could have a positive impact on the participants' everyday life and adherence to treatment for psychosis.…”

“…EF impairments are also found among persons with psychosis risk [8]. Psychosis risk syndromes include attenuated positive symptoms, brief intermittent psychotic symptoms and genetic risk combined with deteriorated functioning [9,10].…”

The lived experience of psychosis: a bottom‐up review co‐written by experts by experience and academics

“…Accumulation of further risk factors during infancy and young adulthood 40 may lead to the emergence of a clinical high‐risk state for psychosis; this stage is often termed “prodromal” in the retrospective accounts of individuals with the lived experience. The prodromal stage is characterized by attenuated psychotic symptoms that can last years, do not reach the diagnostic threshold for a psychotic disorder, but are typically associated with some degree of functional and cognitive impairment 41‐45 . These manifestations can then progress to a subsequent stage of fully symptomatic mental disorder (first episode of psychosis) and then persist, especially if treated sub‐optimally, leading to a relapsing stage and, for a proportion of cases, a subsequent chronic stage 38 .…”

Effects of omega-3 polyunsaturated fatty acid supplementation on cognitive functioning in youth at ultra-high risk for psychosis: secondary analysis of the NEURAPRO randomised controlled trial

“…Cognitive impairments are well-established features of psychotic disorders and are present when individuals are at ultra-high risk (UHR) for developing a full-threshold disorder. 1 Cognitive deficits have shown to be a pre-existing risk factor for transition to psychosis among UHR individuals, particularly moderate impairments in verbal fluency, working memory, processing speed and verbal memory. 1 , 2 Despite this, few interventions target cognitive functioning in UHR populations.…”

“… 1 Cognitive deficits have shown to be a pre-existing risk factor for transition to psychosis among UHR individuals, particularly moderate impairments in verbal fluency, working memory, processing speed and verbal memory. 1 , 2 Despite this, few interventions target cognitive functioning in UHR populations. 3 Omega-3 polyunsaturated fatty acids ( n −3 PUFAs), such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are primarily consumed through diet and have anti-inflammatory and antioxidant properties.…”