Neuropsychology of subjects with ultra-high risk (UHR) of psychosis: A critical analysis of the literature

Psychometric properties of the Spanish version of the measure of insight into cognition-self-report in psychosis-risk and non-clinical Mexican young adults

AIM

Cognitive disturbances typically precede the onset of overt psychotic symptoms and represent a neurobiological marker for psychosis risk that is also associated with poor functional outcomes. The Measure of Insight into Cognition-Self Report (MIC-SR) is a widely used 12-item questionnaire that assesses the perceived frequency of cognitive impairment in the domains of executing functioning, attention, and memory. However, the MIC-SR is not available in Spanish, one of the most widely spoken languages worldwide. The present study aimed to provide a Spanish version of the MIC-SR and examine its psychometric properties in psychosis-risk and non-clinical Mexican young adults.

METHODS

The sample comprised 621 participants who completed a battery of self-report measures via an online survey. Of the participants, 478 were non-clinical, and 143 met the screening criteria for a clinical high-risk for psychosis (CHR-positive).

RESULTS

Confirmatory Factor Analyses supported a one-factor model, consistent with the findings for the original MIC-SR. The results showed adequate fit indices for the general model and the independent models for both groups, with high Cronbach's alpha coefficients. Furthermore, the CHR-positive group showed more frequent subjective cognitive problems on each of the 12 items, higher total scores, and higher average frequency than the non-clinical group.

CONCLUSION

To our knowledge, this is the first translation of the MIC-SR into Spanish. Using the MIC-SR at the CHR stage may contribute to our understanding of cognitive processes associated with the onset of a psychotic disorder and provide valuable information in the context of detection and early intervention efforts.

Epigenetic Control in Schizophrenia

Schizophrenia is a severe and complex psychiatric condition ranking among the top 15 leading causes of disability worldwide. Despite the well-established heritability component, a complex interplay between genetic and environmental risk factors plays a key role in the development of schizophrenia and psychotic disorders in general. This chapter covers all the clinical evidence showing how the analysis of the epigenetic modulation in schizophrenia might be relevant to understand the pathogenesis of schizophrenia as well as potentially useful to develop new pharmacotherapies.

On Metacognition: Overconfidence in Word Recall Prediction and Its Association with Psychotic Symptoms in Patients with Schizophrenia

A two-factor account has been proposed as an explanatory model for the formation and maintenance of delusions. The first factor refers to a neurocognitive process leading to a significant change in subjective experience; the second factor has been regarded as a failure in hypothesis evaluation characterized by an impairment in metacognitive ability. This study was focused on the assessment of metacognition in patients with schizophrenia. The aims of the study were to measure the overconfidence in metacognitive judgments through the prediction of word list recall and to analyze the correlation between basic neurocognition (memory and executive function) and metacognition through a metamemory test and the severity of psychotic symptoms.

METHOD

Fifty-one participants with a diagnosis of schizophrenia were evaluated. The Positive and Negative Syndrome Scale (PANSS) was used to assess the severity of psychiatric symptoms, and the subtest of metamemory included in the Executive Functions and Frontal Lobe-2 battery (BANFE-2) was used to evaluate overconfidence and underestimation errors, intrusion and perseverative response, total volume of recall, and Brief Functioning Assessment Scale (FAST) for social functioning.

RESULTS

The strongest correlation is observed between overconfidence errors and the positive factor of the PANSS (r = 0.774, p < 0.001). For the enter model in the multiple linear regression (r = 0.78, r2 = 0.61; F = 24.57, p < 0.001), the only significant predictor was overconfidence errors.

CONCLUSION

Our results highlight the relevance of a metacognitive bias of overconfidence, strongly correlated with psychotic symptoms, and support the hypothesis that metacognitive defects contribute to the failure to reject contradictory evidence. From our perspective, these findings align with current mechanistic models of schizophrenia that focus on the role of the prefrontal cortex.

Models of mild cognitive deficits in risk assessment in early psychosis

BACKGROUND

Mild cognitive deficits (MCD) emerge before the first episode of psychosis (FEP) and persist in the clinical high-risk (CHR) stage. This study aims to refine risk prediction by developing MCD models optimized for specific early psychosis stages and target populations.

METHODS

A comprehensive neuropsychological battery assessed 1059 individuals with FEP, 794 CHR, and 774 matched healthy controls (HCs). CHR subjects, followed up for 2 years, were categorized into converters (CHR-C) and non-converters (CHR-NC). The MATRICS Consensus Cognitive Battery standardized neurocognitive tests were employed.

RESULTS

Both the CHR and FEP groups exhibited significantly poorer performance compared to the HC group across all neurocognitive tests (all p < 0.001). The CHR-C group demonstrated poorer performance compared to the CHR-NC group on three sub-tests: visuospatial memory (p < 0.001), mazes (p = 0.005), and symbol coding (p = 0.023) tests. Upon adjusting for sex and age, the performance of the MCD model was excellent in differentiating FEP from HC, as evidenced by an Area Under the Receiver Operating Characteristic Curve (AUC) of 0.895 (p < 0.001). However, when applied in the CHR group for predicting CHR-C (AUC = 0.581, p = 0.008), the performance was not satisfactory. To optimize the efficiency of psychotic risk assessment, three distinct MCD models were developed to distinguish FEP from HC, predict CHR-C from CHR-NC, and identify CHR from HC, achieving accuracies of 89.3%, 65.6%, and 80.2%, respectively.

CONCLUSIONS

The MCD exhibits variations in domains, patterns, and weights across different stages of early psychosis and diverse target populations. Emphasizing precise risk assessment, our findings highlight the importance of tailored MCD models for different stages and risk levels.

Neurocognitive consequences of adolescent sleep disruptions and their relationship to psychosis vulnerability: a longitudinal cohort study

Adolescence is a key period for neurocognitive maturation where deviation from normal developmental trajectories may be tied to adverse mental health outcomes. Cognitive disruptions have been noted in populations at risk for psychosis and are known to accompany periods of sleep deprivation. This study aims to assess the role of cognition as a mediator between sleep disruptions and psychosis risk. A cohort of 3801 high school students (51% female, mean age = 12.8, SD = 0.45 years) was recruited from 31 Montreal high schools. Measures of sleep, psychotic-like experiences, inhibition, working memory, perceptual reasoning, and delayed recall were collected from participants on a yearly basis over the five years of their high school education. A multi-level model mediation analysis was performed controlling for sex and time squared. Response inhibition was shown to be associated with, and to mediate (B = -0.005, SD = 0.003, p = 0.005*) the relationship between sleep disruptions (B = -0.011, SD = 0.004, p < 0.001*) and psychotic-like experiences (B = 0.411, SD = 0.170, p = 0.005*). Spatial working memory deficits on a given year were associated with a higher frequency of psychotic-like experiences that same year (B = -0.046, SD = 0.018, p = 0.005*) and the following year (B = -0.051, SD = 0.023, p = 0.010*), but were not associated with sleep disturbances. No significant associations were found between our variables of interest and either delayed recall or perceptual reasoning at the within person level. Findings from this large longitudinal study provide evidence that the association between sleep disruptions and psychosis risk is specifically mediated by inhibitory rather than general cognitive impairments. The association of spatial working memory, response inhibition, and sleep disruptions with psychotic-like experiences suggests that these factors may represent potential targets for preventative interventions.

Cognitive predictors of transition and remission of psychosis risk syndrome in a child and adolescent sample: longitudinal findings from the CAPRIS study

Cognitive impairments are proposed as predictors in the differentiation between subjects with psychosis risk syndrome (PRS) who will develop a psychotic disorder (PRS-P) and those who will not (PRS-NP). More in-depth study of the PRS-NP group could contribute to defining the role of cognitive alterations in psychosis. This study aims to analyze cognition of children and adolescents with PRS in terms of their clinical outcome at 18-month follow-up (psychosis, remission, and non-remission) and of determinate predictors of transition to psychosis and remission of PRS. The method is two-site, naturalistic, longitudinal study design, with 98 help-seeking adolescents with PRS and 64 healthy controls (HC). PRS-P (n = 24) and PRS-NP (n = 74) participants were clinically and cognitively assessed at baseline, and when full-blown psychotic disorder had developed or at 18-month follow-up. PRS-P subjects showed lower scores at baseline in processing speed, visuospatial memory, attention, and executive function (cognitive flexibility/processing speed) compared to HC. PRS-NP subjects showed lower baseline scores in verbal working memory and verbal fluency compared to HC. This deficit is also observed in the PRS group of participants still presenting attenuated psychotic symptoms at 18-month follow-up, while PRS subjects in remission showed a similar cognitive profile to HC subjects. Baseline score on processing speed, measured with a coding task, appeared to be a predictive variable for the development of a psychotic disorder. Performance in verbal working memory was predictive of remission in the PRS-NP. Post hoc comparisons indicate the need for careful interpretation of cognitive markers as predictors of psychosis. Cognitive impairments are present in both PRS-P and PRS-NP. Those individuals who recover from PRS show baseline cognitive performance comparable to the HC group. Together with sociodemographic variables, this observation could help in the differentiation of a variety of PRS trajectories in children and adolescents.

Are the epigenetic changes predictive of therapeutic efficacy for psychiatric disorders? A translational approach towards novel drug targets

The etiopathogenesis of mental disorders is not fully understood and accumulating evidence support that clinical symptomatology cannot be assigned to a single gene mutation, but it involves several genetic factors. More specifically, a tight association between genes and environmental risk factors, which could be mediated by epigenetic mechanisms, may play a role in the development of mental disorders. Several data suggest that epigenetic modifications such as DNA methylation, post-translational histone modification and interference of microRNA (miRNA) or long non-coding RNA (lncRNA) may modify the severity of the disease and the outcome of the therapy. Indeed, the study of these mechanisms may help to identify patients particularly vulnerable to mental disorders and may have potential utility as biomarkers to facilitate diagnosis and treatment of psychiatric disorders. This article summarizes the most relevant preclinical and human data showing how epigenetic modifications can be central to the therapeutic efficacy of antidepressant and/or antipsychotic agents, as possible predictor of drugs response.

A polymorphism in the glutamate metabotropic receptor 7 is associated with cognitive deficits in the early phases of psychosis

Schizophrenia is an illness characterized by positive symptoms, negative symptoms, and cognitive impairments. Cognitive impairments occur before the onset of psychosis and could reflect glutamatergic dysregulation. Thus, identifying associations between genetic variations in genes coding for glutamatergic receptors and cognitive impairment in schizophrenia may help in understanding the basis of these deficits and in identifying potential drug targets. In a discovery cohort of 144 first-episode of psychosis patients (FEP), we genotyped 58 candidate Single Nucleotide Polymorphisms (SNPs) located in NMDA and metabotropic glutamatergic receptors. These SNPs were selected according to the results from the Psychiatric Genomic Consortium and were tested for association with intellectual quotient (IQ) as assessed with the Wechsler Intelligence Scales. For replication, we used the ICAAR cohort including 121 ultra-high-risk patients (UHR) with the same cognitive assessment. A polymorphism located in GRM7, rs1396409, was significantly associated with performance IQ in the discovery cohort of FEP. This association was replicated in the UHR cohort. This polymorphism is also associated with total IQ and verbal IQ in the merged dataset, with a predominant effect on the arithmetic subtest. The rs1396409 polymorphism is significantly associated with cognitive impairment during the onset of psychosis. This genetic association highlights the possible impact of glutamatergic genes in cognitive deficits in the early phases of psychosis and enforces the interest for new therapeutic interventions targeting the glutamatergic pathway.

Associations between symptom and neurocognitive dimensions in clinical high risk for psychosis

Introduction

Clinical high risk for psychosis (CHR) is associated with mild cognitive impairments. Symptoms are clustered into positive, negative and disorganization symptoms. The association between specific symptom dimensions and cognitive functions remains unclear. The aim of this study was to investigate the associations between cognitive functions and positive, negative, and disorganization symptoms.

Method

53 CHR subjects fulfilling criteria for attenuated psychotic syndrome in the Structural Interview for Prodromal Syndromes (SIPS) were assessed for cognitive function. Five cognitive domain z-scores were defined by contrasting with observed scores of a group of healthy controls (n = 40). Principal Components Analyses were performed to construct general cognitive composite scores; one using all subtests and one using the cognitive domains. Associations between cognitive functions and symptoms are presented as Spearman's rank correlations and partial Spearman's rank correlations adjusted for age and gender.

Results

Positive symptoms were negatively associated with executive functions and verbal memory, and disorganization symptoms with poorer verbal fluency. Negative symptoms were associated with better executive functioning. There were no significant associations between the general cognitive composites and any of the symptom domains, except for a trend for positive symptoms.

Conclusion

In line with previous research, data indicated associations between positive symptoms and poorer executive functioning. Negative symptoms may not be related to executive functions in CHR the same way as in psychosis. Our results could indicate that attenuated positive symptoms are more related to cognitive deficits in CHR than positive symptoms in schizophrenia and FEP.

Cognitive Patterns and Conversion in a Representative Sample of Individuals at Risk for Psychosis

ABSTRACT

Clinical high-risk (CHR) individuals belong to a heterogeneous group, of which only a few will cross the threshold for a clinical diagnosis. Cognitive disturbances are present in CHR subjects and may be indicative of transition. Our study aims to identify such deficits in a representative CHR for psychosis sample. Our sample comprised 92 CHR individuals and 54 controls from a representative cohort of the general population. They were followed up for a mean of 2.5 years, with 15 individuals converting to schizophrenia or other Diagnostic and Statistical Manual of Mental Disorders, 5th Edition diagnoses. Neurocognitive assessment was performed with the University of Pennsylvania Computerized Neuropsychological Testing, and CHR status was assessed with the Structured Interview for Prodromal Syndromes (SIPS). Baseline scores were entered in a latent profile analysis model. Our study brought forward a four-class model on cognitive performance. One class displayed better performance, whereas the other three performed worse, all compared with controls. The class with lower executive function also had the highest score on disorganized communication (SIPS P5 = 1.36, p < 0.05), although unrelated to conversion. Among the low performers, the class significantly related to conversion (p = 0.023) had the highest score in decreased expression of emotion (SIPS N3 = 0.85, p < 0.05). Our study brings new and relevant data on non-help-seeking CHR individuals and the relationship between cognitive patterns and conversion. We have highlighted a specific cognitive signature, associated with negative symptoms, which represents a stable trait with presumed lower conversion to a psychiatric illness.

Influence of polygenic risk scores for schizophrenia and resilience on the cognition of individuals at-risk for psychosis

Cognitive impairment is a core feature of schizophrenia which precedes the onset of full psychotic symptoms, even in the ultra-high-risk stage (UHR). Polygenic risk scores (PRS) can be computed for many psychiatric disorders and phenotyping traits, including scores for resilience. We explored the correlations between several PRS and neurocognition in UHR individuals. We included 107 UHR individuals; 29.9% of them converted to psychosis (UHR-C) while 57.0% did not (UHR-NC) during the 1-year follow-up. Cognitive performances were assessed with the Wechsler Adult Intelligence Scale estimating the Intelligence Quotient (IQ), the Trail Making Test, the verbal fluency, the Stroop test, and the Wisconsin card sorting test. Linear regression models were used to test their association with the PRS for schizophrenia, bipolar disorder, major depression, ADHD, cross-disorders, cognitive performance, intelligence, education attainment, and resilience to schizophrenia. UHR-C had a lower IQ than UHR-NC. The PRS for schizophrenia negatively correlated with IQ, while the PRS for cognitive performance and for resilience positively correlated with IQ. PRS for schizophrenia showed a significant correlation with working memory and processing speed indices. PRS for schizophrenia showed a higher effect on IQ in UHR-NC, and UHR-NC with high PRS for schizophrenia had a similar IQ as UHR-C. Conversely, UHR-C with a high PRS for resilience performed as well as UHR-NC. Our findings suggest that cognitive deficits may predate the onset of psychosis. The genetic architecture of schizophrenia seems to impacts the cognition in UHR-NC. Cognition is also mediated by PRS for resilience.

[From relationship to therapeutic alliance with adolescents and young adults at risk of psychotic transition: The perspective of mental health professionals. An exploratory study]

Introduction : Psychotic disorders usually begin during adolescence or early adulthood. The first psychotic symptoms are said to be attenuated in their prodromal phase. It is essential to identify them and initiate follow-up as early as possible to limit the severity of symptoms or even prevent a psychotic transition. However, there is still some uncertainty about the progression of symptoms. The aim of this exploratory study was to show the difficulties that surround the construction of a therapeutic alliance in this context.Methodology : The method adopted was a field survey.Results : Uncertainty about the development of disorders and their worsening and the fact that they are assessed by evaluating the patient's functional weaknesses led professionals to develop a relationship based on knowledge that is acquired empirically and that is in line with a phenomenological approach. Thus, professionals mobilized dynamic and interactive communication techniques to try to forge a therapeutic alliance.Conclusion : It has been shown that professionals seek to build a therapeutic alliance with young people presenting an uncertain evolution toward psychosis using a phenomenological, personalized, and pragmatic logic.

No Effects of Cognitive Remediation on Cerebral White Matter in Individuals at Ultra-High Risk for Psychosis-A Randomized Clinical Trial

BACKGROUND

Individuals at ultra-high risk for psychosis (UHR) present with subtle alterations in cerebral white matter (WM), which appear to be associated with clinical and functional outcome. The effect of cognitive remediation on WM organization in UHR individuals has not been investigated previously.

METHODS

In a randomized, clinical trial, UHR individuals aged 18 to 40 years were assigned to treatment as usual (TAU) or TAU plus cognitive remediation for 20 weeks. Cognitive remediation comprised 20 x 2-h sessions of neurocognitive and social-cognitive training. Primary outcome was whole brain fractional anisotropy derived from diffusion weighted imaging, statistically tested as an interaction between timepoint and treatment group. Secondary outcomes were restricted to five predefined region of interest (ROI) analyses on fractional anisotropy, axial diffusivity, radial diffusivity and mean diffusivity. For significant timepoint and treatment group interactions within these five ROIs, we explored associations between longitudinal changes in WM and cognitive functions/clinical symptoms. Finally, we explored dose-response effects of cognitive remediation on WM.

RESULTS

A total of 111 UHR individuals were included. Attrition-rate was 26%. The cognitive remediation group completed on average 12 h of neurocognitive training, which was considerably lower than per protocol. We found no effect of cognitive remediation on whole-brain FA when compared to treatment as usual. Secondary ROI analyses revealed a nominal significant interaction between timepoint*treatment of AD in left medial lemniscus (P=0.016) which did not survive control for multiple comparisons. The exploratory test showed that this change in AD correlated to improvements of mental flexibility in the cognitive remediation group (p=0.001). We found no dose-response effect of neurocognitive training on WM.

CONCLUSIONS

Cognitive remediation comprising 12 h of neurocognitive training on average did not improve global or regional WM organization in UHR individuals. Further investigations of duration and intensity of cognitive training as necessary prerequisites of neuroplasticity-based changes are warranted.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, identifier NCT02098408.

Models Predicting Psychosis in Patients With High Clinical Risk: A Systematic Review

OBJECTIVE

The present study reviews predictive models used to improve prediction of psychosis onset in individuals at clinical high risk for psychosis (CHR), using clinical, biological, neurocognitive, environmental, and combinations of predictors.

METHODS

A systematic literature search on PubMed was carried out (from 1998 through 2019) to find all studies that developed or validated a model predicting the transition to psychosis in CHR subjects.

RESULTS

We found 1,406 records. Thirty-eight of them met the inclusion criteria; 11 studies using clinical predictive models, seven studies using biological models, five studies using neurocognitive models, five studies using environmental models, and 18 studies using combinations of predictive models across different domains. While the highest positive predictive value (PPV) in clinical, biological, neurocognitive, and combined predictive models were relatively high (all above 83), the highest PPV across environmental predictive models was modest (63%). Moreover, none of the combined models showed a superiority when compared with more parsimonious models (using only neurocognitive, clinical, biological, or environmental factors).

CONCLUSIONS

The use of predictive models may allow high prognostic accuracy for psychosis prediction in CHR individuals. However, only ten studies had performed an internal validation of their models. Among the models with the highest PPVs, only the biological and neurocognitive but not the combined models underwent validation. Further validation of predicted models is needed to ensure external validity.

Alterations in white matter microstructure and cortical thickness in individuals at ultra-high risk of psychosis: A multimodal tractography and surface-based morphometry study

There is increasing evidence of white matter (WM) and grey matter pathology in subjects at ultra-high risk of psychosis (UHR), although a limited number of diffusion-weighted magnetic resonance imaging (DW-MRI) and surface-based morphometry (SBM) studies have revealed anatomically inconsistent results. The present multimodal study applies tractography and SBM to analyze WM microstructure, whole-brain cortical anatomy, and potential interconnections between WM and grey matter abnormalities in UHR subjects. Thirty young male UHR patients and 30 healthy controls underwent DW-MRI and T1-weighted MRI. Fractional anisotropy; mean, radial, and axial diffusivity in 18 WM tracts; and vertex-based cortical thickness, area, and volume were analyzed. We found increased radial diffusivity in the left anterior thalamic radiation and reduced bilateral thickness across the frontal, temporal, and parietal cortices. No correlations between WM and grey matter abnormalities were identified. These results provide further evidence that WM microstructure abnormalities and cortical anatomical changes occur in the UHR state. Disruption of structural connectivity in the prefrontal-subcortical circuitry, likely caused by myelin pathology, and cortical thickness reduction affecting the networks presumably involved in processing and coordination of external and internal information streams may underlie the widespread deficits in neurocognitive and social functioning that are consistently reported in UHR subjects.

Preliminary study of higher-order language and extralinguistic impairments in individuals with high clinical risk of psychosis and first episode of schizophrenia

AIM

Higher-order language functions are associated with understanding indirect speech acts, lexical-semantic processes, the understanding and production of prosody, discourse production and comprehension. Only a few studies imply that language abnormalities may be present in individuals at ultra-high risk for psychosis (UHR) and first-episode of schizophrenia (FE). The purpose of this study was to test the presence of higher-order language dysfunctions in UHR and FE subjects using a standardized comprehensive test battery.

METHODS

Twenty patients experiencing FE schizophrenia, 33 UHR individuals and 20 healthy controls (HC) took part in the study. Higher-order language and extralinguistic abilities were evaluated using the Right Hemisphere Language Battery (RHLB-PL). The battery consisted of tests covering the comprehension of implicit information, lexico-semantic processing, understanding humour, making inappropriate remarks and comments, understanding and explaining metaphors, understanding prosody and appropriateness of behaviour in communication settings.

RESULTS

The UHR patients scored lower than HC when comprehending implicit information, discourse and in areas associated with the effectiveness of interpersonal communication; however, they scored higher than the FE participants in explanation of metaphors and processing language information in the context of general knowledge. The FE participants scored lower than healthy controls in comprehension of implicit information, explanation of metaphors, discourse understanding, processing language information in the context of general knowledge and effectiveness of interpersonal communication.

CONCLUSIONS

The higher-order language dysfunctions mediated by the right hemisphere appear to be present in subjects at UHR of schizophrenia and those experiencing their FE. The results may play a crucial role in diagnostic processes.

Neurocognition as a predictor of transition to psychotic disorder and functional outcomes in ultra-high risk participants: Findings from the NEURAPRO randomized clinical trial

BACKGROUND

Neurocognitive impairments experienced by individuals at ultra-high risk (UHR) for psychosis are potential predictors of outcome within this population, however there is inconsistency regarding the specific neurocognitive domains implicated. This study aimed to examine whether baseline neurocognition predicted transition to psychosis, or functional outcomes, at medium-term (mean = 3.4 years) follow-up, while controlling for other clinical/treatment variables associated with transition to psychosis.

METHOD

Analysis of data collected as part of a multi-centre RCT of omega-3 fatty acids and cognitive-behavioural case management (NEURAPRO) for UHR individuals was conducted on the 294 participants (134 males, 160 females) who completed neurocognitive assessment (Brief Assessment of Cognition for Schizophrenia) at baseline. Transition to psychosis was determined using the Comprehensive Assessment of At-Risk Mental States (CAARMS), and functioning was measured with the Global Functioning: Social and Role Scales.

RESULTS

Mean baseline z-scores indicated that UHR participants performed a quarter to half a standard deviation below normative means in all domains (range mean z = -0.24 to -0.47), except for executive functioning (mean z = 0.16). After adjusting for covariates, poorer Executive (p = .010) and Motor (p = .030) functions were predictive of transition to psychosis. Processing Speed and Verbal Fluency were significant predictors of role functioning at 12 months (p = .004), and social functioning at medium-term follow-up (p = .015), respectively.

CONCLUSIONS

Neurocognitive abilities are independent predictors of both transition to psychosis and functional outcomes within the UHR population. Further research is needed to determine the best combination of risk variables in UHR individuals for prediction of psychosis transition, functioning and other psychopathology outcomes.

Neurocognitive dysfunction in subjects at clinical high risk for psychosis: A meta-analysis

Findings of neurocognitive dysfunction in subjects at Clinical High Risk for Psychosis (CHR-P) have been controversial. This meta-analysis systematically examined studies of neurocognitive functions using the MATRICS Consensus Cognitive Battery (MCCB) in CHR-P. An independent literature search of both English and Chinese databases was conducted by two reviewers. Standardized mean difference (SMD) was calculated using a random effects model to evaluate the effect size of the meta-analytic results. Six case-control studies (n = 396) comparing neurocognitive functions between CHR-P subjects (n = 197) and healthy controls (n = 199) using the MCCB were identified; 4 (66.7%) studies were rated as "high quality". Compared to healthy controls, CHR-P subjects showed impairment with large effect size in overall cognition (n = 128, SMD = -1.00, 95%CI: -1.38, -0.63, P < 0.00001; I² = 2%), processing speed (SMD = -1.21) and attention/vigilance (SMD = -0.83), and with medium effect size in working memory (SMD = -0.76), reasoning and problem solving (SMD = -0.71), visual (SMD = -0.68) and verbal learning (SMD = -0.67). No significant difference between CHR-P subjects and controls was found regarding social cognition (SMD = -0.33, 95%CI: -0.76, 0.10, P = 0.14; I² = 70%) with small effect size. Apart from social cognition, CHR-P subjects performed worse than healthy control in all MCCB cognitive domains, particularly in processing speed, attention/vigilance and working memory.