Neurocognitive functioning of subjects with putative pre-psychotic states and early psychosis

Longitudinal change in neurocognitive functioning in children and adolescents at clinical high risk for psychosis: a systematic review

Clinical high risk of psychosis (CHR-P) population has become an attractive area of interest in preventing transitions to psychosis. The consequences of developing a psychotic disorder may be worse in cases of early onset. Thus, childhood and adolescence represent a critical developmental window, where opportunities to gain social and adaptive abilities depend on the individuals' neurocognitive performance. There have been previous syntheses of the evidence regarding neurocognitive functioning in CHR-P individuals and its longitudinal changes. However, there has been less focus on children and adolescents at CHR-P. A multistep literature search was performed from database inception until July 15th, 2022. PRIMSA/MOOSE compliant systematic review and PROSPERO protocol were used to identify studies reporting on longitudinal changes in neurocognitive functioning in children and adolescents (mean age of sample ≤ 18 years) at CHR-P and matched healthy control (HC) group. A systematic review of identified studies was then undertaken. Three articles were included, resulting in a total sample size of 151 CHR-P patients [mean (SD) age, 16.48 (2.41) years; 32.45% female] and 64 HC individuals [mean (SD) age, 16.79 (2.38) years; 42.18% female]. CHR-P individuals had worse outcomes in verbal learning, sustained attention and executive functioning domains compared to HC. Individuals taking antidepressants had better outcomes in verbal learning in contrast with those taking antipsychotics. In children and adolescents, neurocognition may be already impaired before the psychosis onset, and remains stable during the transition to psychosis. Further study should be performed to obtain more robust evidence.

Cognitive trajectories following onset of psychosis: a meta-analysis

BACKGROUND

Cognitive impairment is a core feature of schizophrenia, associated with poor functional outcomes. The course of cognitive function in the years following illness onset has remained a subject of debate, with a previous analysis finding no worsening, providing support for the neurodevelopmental model of schizophrenia. Since then, many more studies have reported on longitudinal cognitive performance in early psychosis, with some indicating deterioration, which does not align with this view.

AIMS

This study aims to quantitatively review the literature on the longitudinal trajectory of cognitive deficits in the years following psychosis onset, in comparison with healthy controls. It is the first to also synthesise longitudinal data on social cognition.

METHOD

Electronic databases ('PubMed', 'PsycInfo' and 'Scopus') were searched (to end September 2021). Meta-analyses of 25 longitudinal studies of cognition in early psychosis were conducted (1480 patients, 789 health controls). Unlike previous analyses, randomised controlled trials and those with multiple cognitive testing periods within the first year were excluded to minimise bias (PROSPERO, ID: CRD42021241525).

RESULTS

Small improvements were observed for global cognition (g = 0.25, 95% CI 0.17-0.33) and individual cognitive domains, but these were comparable with healthy controls and likely an artefact of practice effects.

CONCLUSIONS

There is no evidence of continued cognitive decline or improvement in the early years following psychosis onset, with a need for more studies over longer follow-up periods. Practice effects highlight the importance of including control samples in longitudinal and intervention studies. Further data are needed to evaluate the course of social cognition subdomains.

Neuropsychological Performance Among Individuals at Clinical High-Risk for Psychosis vs Putatively Low-Risk Peers With Other Psychopathology: A Systematic Review and Meta-Analysis

BACKGROUND AND HYPOTHESIS

Youth at clinical high-risk (CHR) for psychosis present with neuropsychological impairments relative to healthy controls (HC), but whether these impairments are distinguishable from those seen among putatively lower risk peers with other psychopathology remains unknown. We hypothesized that any excess impairment among CHR cohorts beyond that seen in other clinical groups is minimal and accounted for by the proportion who transition to psychosis (CHR-T).

STUDY DESIGN

We performed a systematic review and meta-analysis of studies comparing cognitive performance among CHR youth to clinical comparators (CC) who either sought mental health services but did not meet CHR criteria or presented with verified nonpsychotic psychopathology.

STUDY RESULTS

Twenty-one studies were included representing nearly 4000 participants. Individuals at CHR showed substantial cognitive impairments relative to HC (eg, global cognition: g = -0.48 [-0.60, -0.34]), but minimal impairments relative to CC (eg, global cognition: g = -0.13 [-0.20, -0.06]). Any excess impairment among CHR was almost entirely attributable to CHR-T; impairment among youth at CHR without transition (CHR-NT) was typically indistinguishable from CC (eg, global cognition, CHR-T: g = -0.42 [-0.64, -0.19], CHR-NT: g = -0.09 [-0.18, 0.00]; processing speed, CHR-T: g = -0.59 [-0.82, -0.37], CHR-NT: g = -0.12 [-0.25, 0.07]; working memory, CHR-T: g = -0.42 [-0.62, -0.22], CHR-NT: g = -0.03 [-0.14, 0.08]).

CONCLUSIONS

Neurocognitive impairment in CHR cohorts should be interpreted cautiously when psychosis or even CHR status is the specific clinical syndrome of interest as these impairments most likely represent a transdiagnostic vs psychosis-specific vulnerability.

Cognitive Dysfunction as a Risk Factor for Psychosis

The current chapter summarizes recent evidence for cognition as a risk factor for the development of psychosis, including the range of cognitive impairments that exist across the spectrum of psychosis risk symptoms. The chapter examines several possible theories linking cognitive deficits with the development of psychotic symptoms, including evidence that cognitive deficits may be an intermediate risk factor linking genetic and/or neural metrics to psychosis spectrum symptoms. Although there is not strong evidence for unique cognitive markers associated specifically with psychosis compared to other forms of psychopathology, psychotic disorders are generally associated with the greatest severity of cognitive deficits. Cognitive deficits precede the development of psychotic symptoms and may be detectable as early as childhood. Across the psychosis spectrum, both the presence and severity of psychotic symptoms are associated with mild to moderate impairments across cognitive domains, perhaps most consistently for language, cognitive control, and working memory domains. Research generally indicates the size of these cognitive impairments worsens as psychosis symptom severity increases. The chapter points out areas of unclarity and unanswered questions in each of these areas, including regarding the mechanisms contributing to the association between cognition and psychosis, the timing of deficits, and whether any cognitive systems can be identified that function as specific predictors of psychosis risk symptoms.

Meta-analysis of longitudinal neurocognitive performance in people at clinical high-risk for psychosis

Persons at clinical high-risk for psychosis (CHR) are characterised by specific neurocognitive deficits. However, the course of neurocognitive performance during the prodromal period and over the onset of psychosis remains unclear. The aim of this meta-analysis was to synthesise results from follow-up studies of CHR individuals to examine longitudinal changes in neurocognitive performance. Three electronic databases were systematically searched to identify articles published up to 31 December 2021. Thirteen studies met inclusion criteria. Study effect sizes (Hedges' g) were calculated and pooled for each neurocognitive task using random-effects meta-analyses. We examined whether changes in performance between baseline and follow-up assessments differed between: (1) CHR and healthy control (HC) individuals, and (2) CHR who did (CHR-T) and did not transition to psychosis (CHR-NT). Meta-analyses found that HC individuals had greater improvements in performance over time compared to CHR for letter fluency (g = -0.32, p = 0.029) and digit span (g = -0.30, p = 0.011) tasks. Second, there were differences in longitudinal performance of CHR-T and CHR-NT in trail making test A (TMT-A) (g = 0.24, p = 0.014) and symbol coding (g = -0.51, p = 0.011). Whilst CHR-NT improved in performance on both tasks, CHR-T improved to a lesser extent in TMT-A and had worsened performance in symbol coding over time. Together, neurocognitive performance generally improved in all groups at follow-up. Yet, evidence suggested that improvements were less pronounced for an overall CHR group, and specifically for CHR-T, in processing speed tasks which may be a relevant domain for interventions aimed to enhance neurocognition in CHR populations.

A systematic review of premorbid cognitive functioning and its timing of onset in schizophrenia spectrum disorders

Cognitive impairments are core features of established schizophrenia spectrum disorders (SSD). However, it remains unclear whether specific cognitive functions are differentially impaired pre-onset and at what age these impairments can be detected. The purpose of this review was to elucidate these issues through a systematic summary of results from longitudinal studies investigating impairment in specific cognitive domains as antecedents of SSD. Relevant studies were identified by electronic and manual literature searches and included any original study of cognitive domains any time pre-onset of SSDs that included a control group. Effect sizes were calculated by domain for studies comparing high-risk participants who developed SSD with those who did not. The strongest evidence for impairment pre-onset was for mental processing speed, verbal learning and memory, executive function, and social cognition. Some verbal impairments, like language abilities at age 3 and verbal learning and memory at age 7, may develop as static deficits. Conversely, some non-verbal impairments, like mental processing speed, visuospatial abilities, and visual working memory manifest as developmental lag and become significant later in life. Most effect sizes were small to moderate, except for verbal fluency (d' = 0,85), implying this impairment as central in high-risk participants who develop SSD. The present review documents extensive cognitive impairments pre-onset of SSD, and that these impairments start early in life, in line with the neurodevelopmental hypothesis of schizophrenia. Increased knowledge about cognitive impairments preonset can provide a better basis for understanding the complex pathogenesis of SSD as well as informing cognitive remediation programs.

Outcomes for first-episode psychosis after entry via an at-risk mental state clinic compared to direct entry to a first episode of psychosis service: A systematic review and meta-analysis

OBJECTIVE

Early intervention for psychosis services have been established worldwide and consist of specialist services for those with the At-Risk Mental State (ARMS) and a first episode of psychosis (FEP). This systematic review identified the literature on the outcomes of people who initially presented via an ARMS clinic and later transitioned to a psychotic disorder (UHR-T), compared to those who presented directly to an EI service with a FEP (FEP-D). The outcomes examined were (i) symptomatic (ii) functional, (iii) morbidity and mortality (including physical health) and (iv) service-usage.

METHOD

A systematic search strategy was employed using three databases: MEDLINE, PsycInfo, and EMBASE. Studies published in English and that compared any of the above outcomes in a cohort of people with a first episode of psychosis who initially presented via an ARMS clinic to those who presented directly to a FEP service were included. Meta-analysis was performed for any outcome data from at least two studies.

RESULTS

A total of 988 unique articles were identified and of these, three studies fulfilled the inclusion criteria and these included a total of 78 UHR-T and 253 FEP-D individuals. In the one study examining remission rates, there was no difference observed after one year in the UHR-T and FEP-D groups. In the one study that examined neurocognition, no differences were observed in any of the neurocognitive domains between groups after one year. Two studies examined psychiatric admission rates within one year and one of these found that UHR-T individuals were less likely to have any psychiatric admission (46% vs 68%) and admissions were less likely to be involuntary (30% vs 74%), while the other study found no difference in admission rates. In the meta-analysis, UHR-T individuals had lower odds for any psychiatric hospital admission within one year compared to FEP-D individuals (OR = 0.54, 95% C.I. 0.32 - 0.94, p = .03). No studies examined functional outcomes or mortality and morbidity between the groups.

CONCLUSION

The limited research indicates similar or superior outcomes for people with a FEP who present initially via an ARMS clinic. The reduced psychiatric admission rate is an important potential benefit of ARMS clinics that requires replication.

Follow-up of subjects labelled with putative pre-psychotic states: Viewed from a transdiagnostic clinical high-at-risk mental state (CHARMS) paradigm

BACKGROUND

Follow-up of subjects with putative pre-psychotic states is essential to clarify the transition process to psychosis, while "non-converters" also deserve clinical attention as many may evolve into other psychiatric disorders with diverse outcomes. This study aimed to examine help-seeking individuals who have been labelled at clinical high-risk state but not converting to full-blown psychosis during first two years of follow-up.

METHODS

A retrospective observational cohort study of help-seeking subjects was conducted by reviewing medical records of participants in a previous early psychosis study at the study hospital between 2006 and 2020. We portrayed those who developed first episode psychosis after first 2-year follow-up in detail, and provided sketches of clinical macrophenotypes other than psychosis emerging from subjects among different risk groups.

RESULTS

Among 132 eligible subjects, data of 98 (74.2%) were available for detailed evaluation. Of these, 15 transitioned to first-episode psychosis (11.4%) with time to psychosis from 2 to 11 years, 11 had anxiety spectrum (8.3%), 11 had depressive spectrum (8.3%), 10 had obsessive compulsive (7.6%), 5 had bipolar spectrum disorders (3.8%), 13 had predominantly schizotypal (9.8%) and 4 had other personality traits (3%), and 13 had problems attributable to adjustment or developmental issues (9.8%).

CONCLUSIONS

Various diagnoses, either full- or sub-threshold, appropriately describe the diverse clinical phenomenology of a cohort presenting with non-specific and/or subthreshold psychotic symptoms. The clinical high-at-risk mental state (CHARMS) paradigm provides a reasonable transdiagnostic approach for orienting clinicians' attention toward young subjects seeking mental health help at an early stage of illness to potentially pluripotent trajectories.

Hippocampal avoidance whole-brain radiotherapy without memantine in preserving neurocognitive function for brain metastases: a phase II blinded randomized trial

BACKGROUND

Hippocampal avoidance whole-brain radiotherapy (HA-WBRT) shows potential for neurocognitive preservation. This study aimed to evaluate whether HA-WBRT or conformal WBRT (C-WBRT) is better for preserving neurocognitive function.

METHODS

This single-blinded randomized phase II trial enrolled patients with brain metastases and randomly assigned them to receive HA-WBRT or C-WBRT. Primary endpoint is decline of the Hopkins Verbal Learning Test-Revised (HVLT-R) delayed recall at 4 months after treatment. Neurocognitive function tests were analyzed with a mixed effect model. Brain progression-free survival (PFS) and overall survival (OS) were estimated using the Kaplan-Meier method.

RESULTS

From March 2015 to December 2018, seventy patients were randomized to yield a total cohort of 65 evaluable patients (33 in the HA-WBRT arm and 32 in the C-WBRT arm) with a median follow-up of 12.4 months. No differences in baseline neurocognitive function existed between the 2 arms. The mean change of HVLT-R delayed recall at 4 months was -8.8% in the HA-WBRT arm and +3.8% in the C-WBRT arm (P = 0.31). At 6 months, patients receiving HA-WBRT showed favorable perpetuation of HVLT-R total recall (mean difference = 2.60, P = 0.079) and significantly better preservation of the HVLT-R recognition-discrimination index (mean difference = 1.78, P = 0.019) and memory score (mean difference = 4.38, P = 0.020) compared with patients undergoing C-WBRT. There were no differences in Trail Making Test Part A or Part B or the Controlled Oral Word Association test between the 2 arms at any time point. There were no differences in brain PFS or OS between arms as well.

CONCLUSION

Patients receiving HA-WBRT without memantine showed better preservation in memory at 6-month follow-up, but not in verbal fluency or executive function.

White matter microstructure across brain-based biotypes for psychosis - findings from the bipolar-schizophrenia network for intermediate phenotypes

The B-SNIP consortium identified three brain-based Biotypes across the psychosis spectrum, independent of clinical phenomenology. To externally validate the Biotype model, we used free-water fractional volume (FW) and free-water corrected fractional anisotropy (FA_T) to compare white matter differences across Biotypes and clinical diagnoses. Diffusion tensor imaging data from 167 individuals were included: 41 healthy controls, 55 schizophrenia probands, 47 schizoaffective disorder probands, and 24 probands with psychotic bipolar disorder. Compared to healthy controls, FAt reductions were observed in the body of corpus callosum (BCC) for schizoaffective disorder (d = 0.91) and schizophrenia (d = 0.64). Grouping by Biotype, Biotype 1 showed FAt reductions in the CC and fornix, with largest effect in the BCC (d = 0.87). Biotype 2 showed significant FAt reductions in the BCC (d = 0.90). Schizoaffective disorder individuals had elevated FW in the CC, fornix and anterior corona radiata (ACR), with largest effect in the BCC (d = 0.79). Biotype 2 showed elevated FW in the CC, fornix and ACR, with largest effect in the BCC (d = 0.94). While significant diagnosis comparisons were observed, overall greater discrimination from healthy controls was observed for lower FAt in Biotype 1 and elevated FW in Biotype 2. However, between-group differences were modest, with one region (cerebral peduncle) showing a between-Biotype effect. No between-group effects were observed for diagnosis groupings.

Verbal memory measurement towards digital perspectives in first-episode psychosis: A review

BACKGROUND

Even in the early phases of psychotic spectrum illnesses such as schizophrenia, patients can experience cognitive decline or deficits prior to the onset of psychotic symptoms such as delusions and hallucinations. In this systematic review, we assessed which verbal memory assessments are most widely used in first-episode psychosis and may be applied via digital technologies (smartphone applications, etc.) for use in early detection.

METHODS

In November 2019, we searched for studies measuring verbal memory in first episode psychosis or schizophrenia over the past 10 years on PubMed and PsycINFO. We screened abstracts of these studies and excluded review studies. Full-texts of included studies were used to identify the verbal memory measurement tests, follow-up frequencies, and sample sizes.

RESULTS

We screened 233 reports and found that 120 original research studies measured verbal memory in first episode psychosis over the past 10 years. Four of these studies specified using a computer, 24 (20%) used a paper-pen format, 1(1%) used both, and 91 (76%) studies did not specify their administration tools or suggest there were offered in digital formats. Thirty-five (30%) studies had follow-up measurements of verbal memory, while 85 (70%) had only a single verbal memory measurement.

DISCUSSION

While many scales are commonly used to measure verbal memory in first episode psychosis, they are not often administered via digital technology. There is an emerging opportunity to administer these and other tests via digital technologies for expanding access to early detection of cognitive decline in clinical high risk and first-episode psychosis.

Machine Learning for Differential Diagnosis Between Clinical Conditions With Social Difficulty: Autism Spectrum Disorder, Early Psychosis, and Social Anxiety Disorder

Differential diagnosis in adult cohorts with social difficulty is confounded by comorbid mental health conditions, common etiologies, and shared phenotypes. Identifying shared and discriminating profiles can facilitate intervention and remediation strategies. The objective of the study was to identify salient features of a composite test battery of cognitive and mood measures using a machine learning paradigm in clinical cohorts with social interaction difficulties. We recruited clinical participants who met standardized diagnostic criteria for autism spectrum disorder (ASD: n = 62), early psychosis (EP: n = 48), or social anxiety disorder (SAD: N = 83) and compared them with a neurotypical comparison group (TYP: N = 43). Using five machine-learning algorithms and repeated cross-validation, we trained and tested classification models using measures of cognitive and executive function, lower- and higher-order social cognition and mood severity. Performance metrics were the area under the curve (AUC) and Brier Scores. Sixteen features successfully differentiated between the groups. The control versus social impairment cohorts (ASD, EP, SAD) were differentiated by social cognition, visuospatial memory and mood measures. Importantly, a distinct profile cluster drawn from social cognition, visual learning, executive function and mood, distinguished the neurodevelopmental cohort (EP and ASD) from the SAD group. The mean AUC range was between 0.891 and 0.916 for social impairment versus control cohorts and, 0.729 to 0.781 for SAD vs neurodevelopmental cohorts. This is the first study that compares an extensive battery of neuropsychological and self-report measures using a machine learning protocol in clinical and neurodevelopmental cohorts characterized by social impairment. Findings are relevant for diagnostic, intervention and remediation strategies for these groups.

The Critical Need for Help-Seeking Controls in Clinical High-Risk Research

Despite rapidly growing knowledge of the clinical high-risk (CHR) state for psychosis, the vast majority of case-control studies have relied on healthy volunteers as a reference point for drawing inferences about the CHR construct. Researchers have long recognized that results generated from this design are limited by significant interpretive concerns, yet little attention has been given to how these concerns affect the growing field of CHR research. We argue that overreliance on healthy controls in CHR research threatens the validity of inferences concerning group differences, hinders advances in understanding the development of psychosis, and limits clinical progress. We suggest that the combined use of healthy and help-seeking (i.e., psychiatric) controls is a necessary step for the next generation of CHR research. We then evaluate methods for help-seeking control studies, identify the available CHR studies that have used such designs, discuss select findings in this literature, and offer recommendations for research.

Auditory Event-Related Potentials in Antipsychotic-Free Subjects With Ultra-High-Risk State and First-Episode Psychosis

Background: Auditory event-related potentials (ERPs) have been utilized to study defective information processing of patients with schizophrenia. To delineate the pathophysiological processes from pre-psychotic state to first-episode psychosis, a study on subjects from ultra-high-risk (UHR) state to first-episode psychosis, ideally in an antipsychotic-free condition, can add important information to our understanding. Methods: Patients with UHR state or at their first-episode psychosis (FEP) who were drug-naive or only have been temporarily treated with antipsychotics were assessed by auditory ERPs measurement, including P50/N100 (sensory gating) and duration mismatch negativity (MMN; deviance detection). A group of age-matched healthy subjects served as their controls. Results: A total of 42 patients (23 UHR and 19 FEP) and 120 control subjects were recruited, including 21 pure drug-naive and 21 with very short exposure to antipsychotics. Collapsing FEP and UHR as a patient group, they exhibited significant sensory deficits manifested as larger P50 S2 amplitude, larger N100 ratio, and smaller N100 difference, and significantly less deviance detection response revealed by MMN. Such differences were less significant when treating FEP and UHR separately for comparisons. Comparisons of ERP results between drug-naive subjects and antipsychotic-short-exposure subjects revealed no significant difference in any P50/N100 and MMN parameter. Conclusion: Our study is one of the few studies focused on drug-naive or minimally treated patients at pre- or early-psychotic states. Our results exhibited impaired performance in sensory gating and deviance detection shown by certain parameters. A longitudinal study with larger sample sizes will be helpful to provide more evidence to elucidate the role of antipsychotics on an individual's neurophysiological performance at different stages of psychosis.

Neurocognitive deficits in a transdiagnostic clinical staging model

There is a growing literature which suggests that neurocognitive deficits may be markers of susceptibility for serious mental illness development. This study assessed neurocognitive functioning in a sample of youth at risk of serious mental illness across different clinical stages as described by McGorry and colleagues and compared them to healthy controls. The sample was 243 male and female youths aged 12-26 and included: asymptomatic participants with psychiatric risk factors (Stage 0; n = 41); youth with early mood or anxiety symptoms (Stage 1a; n = 52); youth with attenuated psychiatric syndromes (Stages 1b; n = 108); and healthy controls (n = 42). The neurocognitive battery included IQ measures and the Measurement and Treatment Research to Improve Cognition in Schizophrenia Consensus Cognitive Battery. Participants in Stage 1b had lower scores than healthy controls on the composite score of neurocognitive performance, across all IQ measures, and in the domains of processing speed, working memory, attention and problem solving. They also had lower scores than subjects in Stage 0 across most IQ measures and in the domains of processing speed and working memory. This study increases what is known about neurocognitive performance associated with different stages of serious mental illness development.

Cognitive Deficits in Psychotic Disorders: A Lifespan Perspective

Individuals with disorders that include psychotic symptoms (i.e. psychotic disorders) experience broad cognitive impairments in the chronic state, indicating a dimension of abnormality associated with the experience of psychosis. These impairments negatively impact functional outcome, contributing to the disabling nature of schizophrenia, bipolar disorder, and psychotic depression. The robust and reliable nature of cognitive deficits has led researchers to explore the timing and profile of impairments, as this may elucidate different neurodevelopmental patterns in individuals who experience psychosis. Here, we review the literature on cognitive deficits across the life span of individuals with psychotic disorder and psychotic-like experiences, highlighting the dimensional nature of both psychosis and cognitive ability. We identify premorbid generalized cognitive impairment in schizophrenia that worsens throughout development, and stabilizes by the first-episode of psychosis, suggesting a neurodevelopmental course. Research in affective psychosis is less clear, with mixed evidence regarding premorbid deficits, but a fairly reliable generalized deficit at first-episode, which appears to worsen into the chronic state. In general, cognitive impairments are most severe in schizophrenia, intermediate in bipolar disorder, and the least severe in psychotic depression. In all groups, cognitive deficits are associated with poorer functional outcome. Finally, while the generalized deficit is the clearest and most reliable signal, data suggests specific deficits in verbal memory across all groups, specific processing speed impairments in schizophrenia and executive functioning impairments in bipolar disorder. Cognitive deficits are a core feature of psychotic disorders that provide a window into understanding developmental course and risk for psychosis.

Correlates of neurocognitive functions in individuals at ultra-high risk for psychosis - A 6-month follow-up study

Cognitive deficits are evident at the prodromal phase of psychosis. It has been noted that brain-derived neurotrophic factor (BDNF) is correlated with cognition in both preclinical and clinical studies. However, to our knowledge, no study has evaluated blood BDNF levels and their association with cognitive impairment in individuals at ultra-high risk for psychosis (UHR). We included 13 individuals at UHR and 30 healthy controls (HC) matched by sex, age, and educational level. Plasma BDNF levels were measured at baseline and 6 months. Neurocognitive functions (executive functions, speed of processing, verbal learning and memory, working memory) were examined at 6 months. Regression analyses were conducted to examine the relationship between BDNF levels and cognitive performance. BDNF levels were lower in UHR group than in HC group both at baseline and at 6 months (P = 0.001, and P = 0.007, respectively). There were no associations between plasma BDNF levels and all of the cognitive domains in both groups. Our findings showed that peripheral BDNF levels were not related to cognitive deficits in UHR and HC groups while the lower BDNF level in the former persisted up to 6 months. Further research is needed in a large sample.

From the psychosis prodrome to the first-episode of psychosis: No evidence of a cognitive decline

Cognitive deficits have an important role in the neurodevelopment of schizophrenia and other psychotic disorders. However, there is a continuing debate as to whether cognitive impairments in the psychosis prodrome are stable predictors of eventual psychosis or undergo a decline due to the onset of psychosis. In the present study, to determine how cognition changes as illness emerges, we examined baseline neurocognitive performance in a large sample of helping-seeking youth ranging in clinical state from low-risk for psychosis through individuals at clinical high-risk (CHR) for illness to early first-episode patients (EFEP). At baseline, the MATRICS Cognitive Consensus battery was administered to 322 individuals (205 CHRs, 28 EFEPs, and 89 help-seeking controls, HSC) that were part of the larger Early Detection, Intervention and Prevention of Psychosis Program study. CHR individuals were further divided into those who did (CHR-T; n = 12, 6.8%) and did not (CHR-NT, n = 163) convert to psychosis over follow-up (Mean = 99.20 weeks, SD = 21.54). ANCOVAs revealed that there were significant overall group differences (CHR, EFEP, HSC) in processing speed, verbal learning, and overall neurocognition, relative to healthy controls (CNTL). In addition, the CHR-NTs performed similarly to the HSC group, with mild to moderate cognitive deficits relative to the CTRL group. The CHR-Ts mirrored the EFEP group, with large deficits in processing speed, working memory, attention/vigilance, and verbal learning (>1 SD below CNTLs). Interestingly, only verbal learning impairments predicted transition to psychosis, when adjusting for age, education, symptoms, antipsychotic medication, and neurocognitive performance in the other domains. Our findings suggest that large neurocognitive deficits are present prior to illness onset and represent vulnerability markers for psychosis. The results of this study further reinforce that verbal learning should be specifically targeted for preventive intervention for psychosis.

Episodic memory functions in first episode psychosis and clinical high risk individuals

OBJECTIVE

Individuals with schizophrenia have disproportionate memory impairments when encoding relational versus item-specific information, and when using recollection versus familiarity during retrieval. It is unclear whether this pattern is unique to people with chronic schizophrenia, or if it occurs in individuals after a first episode of psychosis (FE), or when at clinical high-risk for psychosis (CHR).

METHODS

We administered the Relational and Item-Specific Memory task (RiSE) to 22 CHR, 101 FE, and 58 typically developing (TD) participants. We examined group differences in item and relational encoding, and familiarity-based and recollection-based retrieval using parametric analysis and structural equation modeling (SEM). Longitudinal data allowed us to examine relations between baseline RiSE performance and change in clinical symptoms at 1-year follow-up in the FE group.

RESULTS

Groups did not differ on familiarity. FE and CHR groups were equally impaired on overall recognition accuracy. Although recollection was impaired in both FE and CHR groups following relational encoding, only the FE group had impaired recollection following item encoding. SEM showed atypical relationships between familiarity and recollection, as well as familiarity and item recognition for both the FE and CHR groups. For FE individuals, better baseline recognition accuracy predicted less severe negative symptoms at 1-year follow-up.

CONCLUSIONS

Impaired relational and recollective memory may reflect neurodevelopmental abnormalities predating conversion to psychosis. These memory deficits appear related to negative symptom changes. In contrast, item specific recollection deficits appear to occur after the development of full psychosis. Familiarity appears to be a relatively preserved memory function across the psychosis spectrum.

Correlation of social cognition and neurocognition on psychotic outcome: a naturalistic follow-up study of subjects with attenuated psychosis syndrome

Neurocognitive decline has been observed in patients with psychosis as well as attenuated psychosis syndrome (APS). We tested the hypothesis that APS increases dependence on neurocognition during the interpretation of others’ mental states and that a combination index of Theory of Mind (ToM) and neurocognition improves the predictive accuracy of psychosis conversion. A sample of 83 APS individuals and 90 healthy controls (HC) were assessed by comprehensive cognitive tests. The cohort also completed a one-year follow-up. In the APS group, ToM was associated with an apparent increase in neurocognition, but this trend was not evident in the HC group. Using the new index of combined neurocognition and ToM scores, the sensitivity for predicting psychosis-proneness was 75% and the specificity was 69%. Our data suggest that the correlations between ToM function and neurocognition in APS subjects were stronger than those in healthy controls. A composite index of neurocognition and ToM could improve the predictive validity of a future conversion to psychosis.