Longitudinal change in neurocognition and its relation to symptomatic and functional changes over 2years in individuals at clinical high-risk for psychosis

Timeframe for Conversion to Psychosis From Individuals at Clinical High-Risk: A Quantile Regression

BACKGROUND AND HYPOTHESIS

The time taken for an individual who is at the clinical high-risk (CHR) stage to transition to full-blown psychosis may vary from months to years. This temporal aspect, known as the timeframe for conversion to psychosis (TCP), is a crucial but relatively underexplored dimension of psychosis development.

STUDY DESIGN

The sample consisted of 145 individuals with CHR who completed a 5-year follow-up with a confirmed transition to psychosis within this period. Clinical variables along with functional variables such as the Global Assessment of Function (GAF) score at baseline (GAF baseline) and GAF-drop from the highest score in the past year. The TCP was defined as the duration from CHR identification to psychosis conversion. Participants were categorized into 3 groups based on TCP: "short" (≤6 months, ≤33.3%), "median" (7-17 months, 33.3%-66.6%), and "long" (≥18 months, ≥66.6%). The quantile regression analysis was applied.

STUDY RESULTS

The overall sample had a median TCP of 11 months. Significant differences among the three TCP groups were observed, particularly in GAF-drop (χ2 = 8.806, P = .012), disorganized symptoms (χ2 = 7.071, P = .029), and general symptoms (χ2 = 6.586, P = .037). Greater disorganized symptoms (odds ratio [OR] = 0.824, P = .009) and GAF-drop (OR = 0.867, P = .011) were significantly associated with a shorter TCP, whereas greater general symptoms (OR = 1.198, P = .012) predicted a longer TCP. Quantile regression analysis demonstrated a positive association between TCP and GAF baseline above the 0.7 quantile and a negative association between TCP rank and GAF drop below the 0.5 quantile.

CONCLUSIONS

This study underscores the pivotal role of functional characteristics in shaping TCP among individuals with CHR, emphasizing the necessity for a comprehensive consideration of temporal aspects in early prevention efforts.

Correlations between Negative Symptoms and Cognitive Deficits in Individuals at First Psychotic Episode or at High Risk of Psychosis: A Systematic Review

The present review aims to identify correlations between negative symptoms (NS) and deficits in neurocognition and social cognition in subjects with first-episode psychosis (FEP) and at-high-risk populations (HR). A systematic search of the literature published between 1 January 2005 and 31 December 2022 was conducted on PubMed, Scopus, and PsycInfo. Out of the 4599 records identified, a total of 32 studies met our inclusion/exclusion criteria. Data on a total of 3086 FEP and 1732 HR were collected. The available evidence shows that NS correlate with executive functioning and theory of mind deficits in FEP subjects, and with deficits in the processing speed, attention and vigilance, and working memory in HR subjects. Visual learning and memory do not correlate with NS in either FEP or HR subjects. More inconsistent findings were retrieved in relation to other cognitive domains in both samples. The available evidence is limited by sample and methodological heterogeneity across studies and was rated as poor or average quality for the majority of included studies in both FEP and CHR populations. Further research based on shared definitions of first-episode psychosis and at-risk states, as well as on more recent conceptualizations of negative symptoms and cognitive impairment, is highly needed.

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.

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.

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.

Neurocognitive functioning in patients with first-episode schizophrenia: results of a prospective 15-year follow-up study

To evaluate the course of neuropsychological impairment, patients with first-episode schizophrenia and healthy controls were assessed with a comprehensive test battery at the time of index treatment and after a 5- and 15-year follow-up period. Summary scores for verbal intelligence (VBI), spatial organization, verbal fluency, verbal learning, semantic memory, visual memory, delay/retention rate, short-term memory, visual-motor processing and attention (VSM) and abstraction/flexibility were constructed. Our results show that neurocognitive functioning is impaired already at the onset of schizophrenia and remains stable over the 15-year follow-up period with an improvement in VBI. With regard to the presence of a deficit syndrome, it became apparent that the group with a deficit syndrome showed a deterioration of neurocognitive functions during the follow-up period, most pronounced in VSM. On the other hand, the group without a deficit syndrome showed an improvement in neurocognitive functions at the 15-year follow-up, which exceeded the learning effects of healthy control subjects. Neurocognitive performance at index assessment strongly predicted the performance at the 15-year follow-up. Most likely due to the small sample size, there were only weak associations between treatment with different types of neuroleptics and neurocognitive performance.

Negative Symptoms and Functioning in Youth at Risk of Psychosis: A Systematic Review and Meta-analysis

LEARNING OBJECTIVE

After participating in this activity, learners should be better able to:• Evaluate the relationship between negative symptoms and functioning in youth at clinical high risk for psychosis.

AIM

Youth at CHR for psychosis often demonstrate significant negative symptoms and poor functioning, though the magnitude and direction of the relationship between the two remains unknown. The objective of this systematic review is to summarize the relationship between negative symptoms and functioning in CHR samples.

METHOD

Electronic databases CINAHL, EBM, Embase, MEDLINE, and PsycINFO were searched from inception. Studies were selected if they included any study that reported a relationship between negative symptoms and functioning in youth at clinical high risk (CHR). The correlation coefficient r was converted to Cohen's d, and all random-effects meta-analyses were performed using the transformed values.

RESULTS

Forty-one studies met the inclusion criteria, including a total of 4574 individuals at CHR for psychosis. Negative symptom total scores were significantly associated with poorer global functioning (d, -1.40; 95% CI, -1.82 to -0.98; I = 79.4%; p < .001 [9 studies, n = 782]), social functioning (d, -1.10; 95% CI, -1.27 to -0.93; I = 10.40%; p < .001 [12 studies, n = 811]), and role functioning (d, -0.96; 95% CI, -1.17 to -0.76; I = 41.1%; p < .001 [9 studies, n = 881]). In addition, negative symptoms were consistently associated with poor premorbid functioning. When examining negative symptom domains, avolition, anhedonia, and blunted affect were each significantly and independently associated with poorer social functioning and role functioning. In terms of prediction models, negative symptoms contributed to the prediction of lower functioning across multiple studies.

CONCLUSION

This meta-analysis demonstrates a strong relationship between negative symptoms and functioning in youth at clinical high risk for psychosis.

Longitudinal Cognitive Performance in Individuals at Ultrahigh Risk for Psychosis: A 10-year Follow-up

It remains unclear whether the onset of psychosis is associated with deterioration in cognitive performance. The aim of this study was to examine the course of cognitive performance in an ultrahigh risk (UHR) cohort, and whether change in cognition is associated with transition to psychosis and change in functioning. Consecutive admissions to Personal Assessment and Crisis Evaluation (PACE) Clinic between May 1994 and July 2000 who had completed a comprehensive cognitive assessment at baseline and follow-up were eligible (N = 80). Follow-up ranged from 7.3 to 13.4 years (M = 10.4 years; SD = 1.5). In the whole sample, significant improvements were observed on the Similarities (P = .03), Information (P < .01), Digit Symbol Coding (P < .01), and Trail Making Test-B (P = .01) tasks, whereas performance on the Rey Auditory Verbal Learning Test (Trials 1-3) declined significantly (P < .01) over the follow-up period. Change in performance on cognitive measures was not significantly associated with transition status. Taking time to transition into account, those who transitioned after 1 year showed significant decline on Digit Symbol Coding, whereas those who did not transition improved on this measure (P = .01; effect size [ES] = 0.85). Small positive correlations were observed between improvements in functioning and improvements in performance on Digit Symbol Coding and Arithmetic (0.24, P = .03 and 0.28, P = .01, respectively). In summary, the onset of psychosis was not associated with deterioration in cognitive ability. However, specific findings suggest that immediate verbal learning and memory, and processing speed may be relevant domains for future risk models and early intervention research in UHR individuals.

Fine motor skill and processing speed deficits in young people with psychotic experiences: A longitudinal study

OBJECTIVE

To identify neuropsychological and motor changes from adolescence to early adulthood in young people with psychotic experiences (PE).

METHODS

A community-based sample of 56 young people attended the study over a 9 year follow-up period. Participants were assessed over 3 time-points at T1, T2 and T3 aged x¯ = 11.69, x¯ = 15.80 and x¯ = 18.80 years respectively. PE were assessed using the Kiddie Schedule for Affective and Depressive Symptoms (K-SADS). Neuropsychological assessments, including subtests of the MATRICS battery, and motor assessments were examined at T2 and T3. Two groups were compared: those who ever reported PE during their adolescence or early adulthood (n = 21) and a healthy control group (n = 35). Further group analysis was conducted within the PE group subdividing into those with transient PE (n = 10) and those with persistent PE (n = 11).

RESULTS

At T3, a significant group difference was found between the PE and control groups in the fine motor skill task, the Pegboard task (F = 4.8, p = .03) and the processing speed task, the Digit-Symbol Coding task (F = 5.36, p = .03). Furthermore, a significant group difference was found between the transient PE and control groups on the Digit-Symbol Coding task (F = 5.61, p = .02), while a significant group difference was found between the persistent PE and control groups on the Pegboard task (F = 7.84, p = .01).

CONCLUSION

This study shows that fine motor skill and processing speed deficits persist in young people who report PE, even in those with transient PE. The current research advances the knowledge about the trajectory and precursors of sub-clinical symptoms of psychosis in young people.

Global and Specific Profiles of Executive Functioning in Prodromal and Early Psychosis

Objective: Numerous reports on neurocognitive functioning deficits in individuals at clinical high risk (CHR) and first-episode psychosis (FEP) patients suggest particular deficits in executive functioning (EF). However, to date, most of the studies have administered a single or a few EF tests to participants, and few investigations have examined the different components of EF to identify specific subdomains of relative strength and weakness. Method: Forty CHR subjects, 85 FEP patients, and 85 healthy controls (HCs) were assessed with a neuropsychological battery to elucidate the profiles of EF in the subdomains of shift, attention, fluency, and planning. Results: In the subdomains of shift, attention, and fluency, CHR individuals and FEP patients showed deficits compared to HC. The post hoc analysis revealed that CHR individuals had comparable attention shifting and phonemic fluency compared to FEP. CHR showed intermediate deficits between FEP and HCs in spatial working memory and semantic fluency, and the largest effect size was observed in semantic fluency both for CHR and FEP. Conclusion: Overall, the findings of this study, in addition to providing detailed profiles of EF in prodromal and early psychosis patients, highlight the informative value of the specific subdomains of semantic fluency and spatial working memory.

Neural correlates of cognitive deficits across developmental phases of schizophrenia

Schizophrenia is associated with cognitive deficits across all stages of the illness (i.e., high risk, first episode, early and chronic phases). Identifying the underlying neurobiological mechanisms of these deficits is an important area of scientific inquiry. Here, we selectively review evidence regarding the pattern of deficits across the developmental trajectory of schizophrenia using the five cognitive domains identified by the Research Domain Criteria (RDoC) initiative. We also report associated findings from neuroimaging studies. We suggest that most cognitive domains are affected across the developmental trajectory, with corresponding brain structural and/or functional differences. The idea of a common mechanism driving these deficits is discussed, along with implications for cognitive treatment in schizophrenia.

Negative symptoms mediate the relationship between neurocognition and function in individuals at ultrahigh risk for psychosis

OBJECTIVE

Neurocognition is known to impact functioning in individuals at ultrahigh risk (UHR) for psychosis, but studies investigating potential mediators of this relationship are scarce. Building on evidence from schizophrenia spectrum disorders, the study tested whether negative symptoms and social skills act as mediators between neurocognition and functional outcome in UHR individuals.

METHODS

Ultrahigh risk participants (N = 84) underwent neurocognitive testing using the Brief Assessment of Cognition in Schizophrenia. Social skills and negative symptoms were assessed using the High-Risk Social Challenge task and the Scale for the Assessment of Negative Symptoms respectively. Four instruments were used to assess overall functioning, and one instrument assessed quality of life encompassing social functioning.

RESULTS

The cross-sectional analyses revealed that neurocognition was related to the measures of functioning. Negative symptoms mediated the relationship between neurocognition and four of the five measures of functioning. We did not find social skills to mediate between neurocognition and functioning.

CONCLUSION

Negative symptoms appear to mediate the relationship between neurocognition and functional outcome in UHR individuals, but the finding needs to be confirmed and extended to longitudinal studies. This underscores the importance of focusing on both neurocognition and negative symptoms when aiming at improving the functional outcome of UHR individuals.