Neurocognitive decline in early-onset schizophrenia compared with ADHD and normal controls: evidence from a 13-year follow-up study

Energy in functional brain states correlates with cognition in adolescent-onset schizophrenia and healthy persons

Adolescent-onset schizophrenia (AOS) is a relatively rare and under-studied form of schizophrenia with more severe cognitive impairments and poorer outcome compared to adult-onset schizophrenia. Several neuroimaging studies have reported alterations in regional activations that account for activity in individual regions (first-order model) and functional connectivity that reveals pairwise co-activations (second-order model) in AOS compared to controls. The pairwise maximum entropy model, also called the Ising model, can integrate both first-order and second-order terms to elucidate a comprehensive picture of neural dynamics and captures both individual and pairwise activity measures into a single quantity known as energy, which is inversely related to the probability of state occurrence. We applied the MEM framework to task functional MRI data collected on 23 AOS individuals in comparison with 53 healthy control subjects while performing the Penn Conditional Exclusion Test (PCET), which measures executive function that has been repeatedly shown to be more impaired in AOS compared to adult-onset schizophrenia. Accuracy of PCET performance was significantly reduced among AOS compared to controls as expected. Average cumulative energy achieved for a participant over the course of the fMRI negatively correlated with task performance, and the association was stronger than any first-order associations. The AOS subjects spent more time in higher energy states that represent lower probability of occurrence and were associated with impaired executive function and greater severity of psychopathology suggesting that the neural dynamics may be less efficient compared to controls who spent more time in lower energy states occurring with higher probability and hence are more stable and efficient. The energy landscapes in both conditions featured attractors that corresponded to two distinct subnetworks, namely fronto-temporal and parieto-motor. Attractor basins were larger in the controls than in AOS; moreover, fronto-temporal basin size was significantly correlated with cognitive performance in controls but not among the AOS. The single trial trajectories for the AOS group also showed higher variability in concordance with shallow attractor basins among AOS. These findings suggest that the neural dynamics of AOS features more frequent occurrence of less probable states with shallower attractors, which lack the relation to executive function associated with attractors in control subjects suggesting a diminished capacity of AOS to generate task-effective brain states.

A Bayesian Network Approach to Social and Nonsocial Cognition in Schizophrenia: Are Some Domains More Fundamental than Others?

OBJECTIVES

Social and nonsocial cognition are defined as distinct yet related constructs. However, the relative independence of individual variables-and whether specific tasks directly depend on performance in other tasks-is still unclear. The current study aimed to answer this question by using a Bayesian network approach to explore directional dependencies among social and nonsocial cognitive domains.

STUDY DESIGN

The study sample comprised 173 participants with schizophrenia (71.7% male; 28.3% female). Participants completed 5 social cognitive tasks and the MATRICS Consensus Cognitive Battery. We estimated Bayesian networks using directed acyclic graph structures to examine directional dependencies among the variables.

STUDY RESULTS

After accounting for negative symptoms and demographic variables, including age and sex, all nonsocial cognitive variables depended on processing speed. More specifically, attention, verbal memory, and reasoning and problem solving solely depended on processing speed, while a causal chain emerged between processing speed and visual memory (processing speed → attention → working memory → visual memory). Social processing variables within social cognition, including emotion in biological motion and empathic accuracy, depended on facial affect identification.

CONCLUSIONS

These results suggest that processing speed and facial affect identification are fundamental domains of nonsocial and social cognition, respectively. We outline how these findings could potentially help guide specific interventions that aim to improve social and nonsocial cognition in people with schizophrenia.

Neuropsychological and Symptom Predictors of Diagnostic Persistence in ADHD: A 25-Year Follow-up Study

BACKGROUND

This study extends long-term predictive research on ADHD by including both neuropsychological and symptom measures at baseline in adolescence as predictors of diagnostic persistence 25 years later.

METHODS

Nineteen males with ADHD and 26 healthy controls (HC; M/F = 13/13), were assessed in adolescence and 25 years later. Measurements at baseline included a comprehensive test battery measuring eight neuropsychological domains, an IQ estimate, the Child Behavior Checklist (CBCL), and the Global Assessment Scale of Symptoms. Differences between ADHD Retainers, Remitters, and HC were calculated with ANOVAs, and potential predictions of differences in the ADHD group by linear regression analyses.

RESULTS

Eleven (58%) participants retained their ADHD diagnoses at follow-up. Motor Coordination and Visual perception at baseline predicted diagnosis at follow-up. CBCL Attention problems at baseline in the ADHD group predicted variance in diagnostic status.

CONCLUSION

Lower-order neuropsychological functions related to motor function and perception are important long-time predictors of persistence of ADHD.

Lifespan evolution of neurocognitive impairment in schizophrenia - A narrative review

Cognitive impairment is a well-recognized key feature of schizophrenia. Here we review the evidence on (1) the onset and sensitive periods of change in cognitive impairment before and after the first psychotic episode, and (2) heterogeneity in neurocognitive presentations across cognitive domains between and within individuals. Overall, studies suggest that mild cognitive impairment in individuals who develop schizophrenia or related disorders is already present during early childhood. Cross-sectional studies further suggest increasing cognitive impairments from pre- to post-psychosis onset, with the greatest declines between adolescence, the prodrome, and the first psychotic episode and with some variability between domains. Longitudinal studies with more than 10 years of observation time are scarce but support mild cognitive declines after psychosis onset until late adulthood. Whether and how much this cognitive decline exceeds normal aging, proceeds further in older patients, and is specific to certain cognitive domains and subpopulations of patients remains to be investigated. Finally, studies show substantial heterogeneity in cognitive performance in schizophrenia and suggest a variety of impairment profiles.

This review highlights a clear need for long-term studies that include a control group and individuals from adolescence to old age to better understand critical windows of cognitive change and their predictors. The available evidence stresses the importance of interventions that aim to counter cognitive decline during the prodromal years, as well as careful assessment of cognition in order to determine who will profit most from which cognitive training.

Ten-year course of cognition in first-episode non-affective psychosis patients: PAFIP cohort

BACKGROUND

A large body of research states that cognitive impairment in schizophrenia is static. Nevertheless, most previous studies lack a control group or have small study samples or short follow-up periods.

METHOD

We aimed to address these limitations by studying a large epidemiological cohort of patients with first-episode schizophrenia spectrum disorders and a comparable control sample for a 10-year period.

RESULTS

Our results support the generalized stability of cognitive functions in schizophrenia spectrum disorders considering the entire group. However, the existence of a subgroup of patients characterized by deteriorating cognition and worse long-term clinical outcomes must be noted. Nevertheless, it was not possible to identify concomitant factors or predictors of deterioration (all Ps > 0.05).

CONCLUSIONS

Cognitive functions in schizophrenia spectrum disorder are stable; however, a subgroup of subjects that deteriorate can be characterized.

Cognitive functioning in a group of adolescents at risk for psychosis

Cognitive deficits are a core feature of schizophrenia, and impairments are present in groups at-risk for psychosis. Most at-risk studies include young adults and not younger age-groups, such as adolescents. Participants are usually help-seeking individuals, even though risk factors may also be present in non-help seeking adolescents. We aim to explore cognitive functions in a group of non-help-seeking 15-year-old adolescents at risk for psychosis compared to age- and gender matched controls, including particular focus on specific cognitive domains. Hundred participants (mean age = 15.3) were invited after completing the 14-year-old survey distributed by the Norwegian Mother-, Father- and Child Study. At-risk adolescents were selected based on high scores on 19 items assessing both psychotic experiences and anomalous self-experiences. Matched controls were selected from the same sample. Cognitive functioning was assessed using the MATRICS Consensus Cognitive Battery and IQ using Wechsler's Abbreviated Test of Intelligence. We found that the adolescents at-risk for psychosis had significantly poorer scores than controls on the composite score of the MCCB. IQ scores were also significantly lower in the at-risk group. The results highlight general cognitive deficits as central in a group of non-help-seeking adolescents at-risk for psychosis. Results indicate that the development of cognitive impairments starts early in life in at-risk groups. It is still unclear whether specific cognitive domains, such as verbal learning, are related to psychotic symptoms or may be specifically vulnerable to symptoms of depression and anxiety.

Changes of neurocognitive status in patients with the first-episode psychosis after 18 months of treatment-A prospective cohort study

Neurocognitive symptoms exert the most influence on treatment outcomes over the course of schizophrenia, starting from the first-episode of psychosis (FEP) onwards. Our aim was to analyze the neurocognitive status of FEP compared to healthy controls (HC), and its change after 18 months of treatment. We performed a study in a sample of 159 patients with FEP and 100 HC. We followed the patients up for 18 months after initial assessment with a battery of neurocognitive tests. We observed statistically significant improvement in the majority of neurocognitive tests after 18 months, but several tests of specific neurocognitive domains (verbal memory, language functions, executive functions) did not show significant differences between the two assessments. The results for the majority of tests obtained from patients with FEP after 18 months of treatment showed significant deterioration compared with HC. Although our study showed significant improvement of baseline neurocognitive deficits in FEP with treatment, this varied across domains and overall performance remained below that of HC. Thus, while it seems that treatment of FEP may help to delay or restore neurocognitive deterioration, it is unclear whether specific areas of neurocognitive deterioration (e.g. verbal domain) would benefit from more time or specific treatment approaches.

Pre-attention and Working Memory in ADHD: A 25-Year Follow-Up Study

Objective: The aim of the study was to compare the development of working memory and preliminary stages of attentional processing in individuals with ADHD over a 23- to 25-year period. Method: Individuals with ADHD (n = 19) and healthy controls (n = 26) were followed up after 13 years (T2) and 23 to 25 years (T3) after initial assessment (T1). They were reassessed with diagnostic measures and the Backward masking task (pre-attention) and the Digit span distractibility test with and without distraction conditions (working memory). Results: The ADHD group performed below the healthy controls on all time points on the Digit span distractibility test. On the distractibility condition, we found a selective decline in performance from T2 to T3 for the ADHD group. Conclusion: The results highlight that ADHD individuals continue to display working memory deficits, also in adulthood, thus creating an imperative for cognitive rehabilitation techniques to help address attention difficulties.

Cognitive Performance in Early-Onset Schizophrenia and Attention-Deficit/Hyperactivity Disorder: A 25-Year Follow-Up Study

Early-Onset Schizophrenia (EOS) and Attention Deficit-Hyperactivity Disorder (ADHD) are early- onset neurodevelopmental disorders associated with cognitive deficits. The current study represents the first attempt to compare these groups on a comprehensive cognitive test battery in a longitudinal design over 25 years in order to enhance our knowledge of particular patterns resulting from the interaction between normal maturational processes and different illness processes of these disorders. In the baseline study, 19 adolescents with schizophrenia were compared to 20 adolescents with ADHD and 30 healthy controls (HC), all between 12 and 18 years of age. After 13 years (T2) and after 25 years (T3) they were re-evaluated with the cognitive test battery. A cognitive Composite Score was used in a linear mixed model. The EOS group had a significant cognitive stagnation or deterioration from T1 to T2 compared to HC. However, the EOS group had the most positive change from T2 to T3, supporting a stable level of cognitive performance over the 25 year span. The ADHD group improved or had similar development as the HC group from T1 to T2. They continued to improve significantly compared to the HC group from T2 to T3. Individuals in the EOS group performed more impaired on the cognitive composite score compared to the HC group and the ADHD group at all three time points. Results might indicate a neurodevelopmental pathway of EOS with subnormal cognitive development specific in adolescence. In comparison, the ADHD group had a more consistent cognitive maturation supporting a maturational delay hypothesis of ADHD.

Characteristics of White Matter Structural Networks in Chronic Schizophrenia Treated With Clozapine or Risperidone and Those Never Treated

BACKGROUND

Despite its benefits, a major concern regarding antipsychotic treatment is its possible impact on the brain's structure and function. This study sought to explore the characteristics of white matter structural networks in chronic never-treated schizophrenia and those treated with clozapine or risperidone, and its potential association with cognitive function.

METHODS

Diffusion tensor imaging was performed on a unique sample of 34 schizophrenia patients treated with antipsychotic monotherapy for over 5 years (17 treated with clozapine and 17 treated with risperidone), 17 never-treated schizophrenia patients with illness duration over 5 years, and 27 healthy control participants. Graph theory and network-based statistic approaches were employed.

RESULTS

We observed a disrupted organization of white matter structural networks as well as decreased nodal and connectivity characteristics across the schizophrenia groups, mainly involving thalamus, prefrontal, and occipital regions. Alterations in nodal and connectivity characteristics were relatively milder in risperidone-treated patients than clozapine-treated patients and never-treated patients. Altered global network measures were significantly associated with cognitive performance levels. Structural connectivity as reflected by network-based statistic mediated the difference in cognitive performance levels between clozapine-treated and risperidone-treated patients.

LIMITATIONS

These results are constrained by the lack of random assignment to different types of antipsychotic treatment.

CONCLUSION

These findings provide insight into the white matter structural network deficits in patients with chronic schizophrenia, either being treated or untreated, and suggest white matter structural networks supporting cognitive function may benefit from antipsychotic treatment, especially in those treated with risperidone.

Understanding sex differences in cognitive insight across first-and-multiple episode psychosis

OBJECTIVE

Cognitive insight represents the capacity to self-reflect and consider external feedback when re-evaluating faulty beliefs. It is associated with specific cognitive capacities such as verbal memory, of which there is substantial evidence for sex differences in psychotic disorders. Like more general cognitive capacities, cognitive insight might too be modulated by sex differences.

METHOD

One hundred and seventy-one first episode psychosis (FEP; 123 males, 48 females), and 203 multiple episode psychosis (MEP; 147 males, 56 females) participants completed the Beck Cognitive Insight Scale (BCIS). A two-way MANOVA was conducted on the three BCIS measures (self-reflectiveness, self-certainty, composite index) with sex (male, female) and illness stage (FEP, MEP) as factors, followed by two-way ANOVAs and a post hoc test of simple effects.

RESULTS

The only significant interaction to emerge was between sex and illness stage in self-certainty (F(1, 373) = 5.88, p = .016). A test of simple effects revealed that self-certainty group means were significantly different for males and females in FEP, where females had lower self-certainty than males (p = .053) but not during MEP (p = .119).

CONCLUSION

Sex differences do not modulate cognitive insight in MEP, which may be attributable to females having greater positive symptom severity than males. In FEP however, results revealed that females were significantly less self-certain than males. Lower self-certainty relative to self-reflectiveness predicts treatment response in psychological interventions, and as such future FEP studies should explore sex differences in psychological interventions.

Perinatal complications and executive dysfunction in early-onset schizophrenia

BACKGROUND

The present study examined the association between perinatal obstetric complications and executive dysfunction in early-onset schizophrenia (EOS), compared to healthy controls. Higher incidences of obstetric complications and more severe executive dysfunctions characterize EOS. Research shows extensive brain maturation in newborns, suggesting them to be particularly vulnerable for perinatal insults. Executive function is mainly mediated by the prefrontal cortex, an area that matures last during pregnancy. Thus, exposure to perinatal complications may influence executive dysfunction in EOS.

METHODS

The participants were 19 EOS patients and 54 healthy controls. Executive function was assessed with the D-KEFS Color Word Interference Test and the Wisconsin Card Sorting Test. Information on perinatal obstetric complications and Apgar 5-min scores were obtained from the Norwegian Medical Birth Registry. Associations between perinatal conditions and executive function were studied using stepwise regression analyses.

RESULTS

Perinatal complications, and especially shorter gestational lengths, were significantly associated with significant executive dysfunctions in EOS. Perinatal complications did not affect executive function among healthy controls. A significant relationship between lower Apgar 5-min scores and executive dysfunction was found among both EOS patients and healthy controls.

CONCLUSIONS

Exposure to perinatal complications, and particularly a shorter gestational length, was associated with increased executive dysfunction in EOS. Exposed healthy controls did not exhibit similar executive difficulties, suggesting that the EOS patients seemed especially vulnerable for executive deficits due to perinatal insults. The findings indicate that EOS youths learn more slowly and experience more difficulty with problem-solving, which carry important implications for clinical practice. Lower Apgar 5-min scores were associated with executive dysfunction in both groups. Low Apgar score at 5 min may therefore be an important early indicator of executive difficulties among adolescents, independent of diagnosis.

Negative and disorganized symptoms mediate the relationship between verbal learning and global functioning in adolescents with early-onset psychosis

Neurocognitive deficits are associated with impaired global functioning and psychotic symptoms. However, whether symptoms can mediate the relationship between neurocognition and global functioning in adolescent psychosis is unclear. Here, we investigated if symptoms assessed with the Positive And Negative Syndrome Scale (PANSS), mediated the relationship between neurocognitive performance and global functioning in adolescents with non-affective early-onset psychotic disorders (EOP). Sixty-one adolescent EOP patients (age 12-18 years) from 2 Norwegian clinical cohorts were included. Linear regression models were applied to investigate associations between neurocognitive domains from the MATRICS Consensus Cognitive Battery (MCCB) and global functioning. PANSS symptoms were analyzed using the Wallwork/Fortgang five-factor model. Using the INDIRECT macro for SPSS, mediation effects were tested using bootstrapping with 95% bias corrected confidence intervals. Verbal learning was positively associated with global functioning (P < 0.001) and negatively associated with the disorganized symptom factor (P = 0.002), controlling for age, sex and cohort. Testing of indirect effects, controlling for age, sex and cohort, showed that the Negative (point estimate = 1.56, 95% CI 0.22, 3.47) and Disorganized (point estimate = 1.24, 95% CI 0.05, 3.69) symptom factors significantly mediated the relationship between verbal learning and global functioning. We found that verbal learning, negative and disorganized symptoms influenced global functioning in adolescents with EOP, while reality-distorted positive symptoms did not. These results suggest that assessing these domains in EOP is helpful for planning treatment and rehabilitation programs focusing on functional outcome.

Uncoupled relationship in the brain between regional homogeneity and attention function in first-episode, drug-naïve schizophrenia

The relationship between the cognitive impairment and the structural and functional abnormalities in the brains of patients with schizophrenia (SZ) is not yet clear. This study aims to investigate the relationship, thereby exploring the neuromechanism underlying SZ. We collected multimodal MRI data from 68 first-episode, drug-naïve patients with SZ, and 64 well-matched healthy controls, and used regional homogeneity (ReHo) and gray matter volume (GMV) to assess the functional and structural integrity of the brains, respectively. We then evaluated in the entire brain the correlations between ReHo/GMV and the participants' neuropsychological assessment scores for each group using a partial correlation analysis controlling for age and sex. We found significant uncoupling between attention performance and mean ReHo in the left middle frontal gyrus, right superior/inferior parietal lobe (IPL), right angular gyrus (AG) and right middle/inferior temporal lobe (ITG) in SZ compared with healthy controls. Moreover, we found that the SZ group showed decreased GMV in the right IPL and AG, and a significant coupling between ReHo and GMV in the right ITG. Our findings suggest that the attention dysfunction found in SZ may be associated with the structural and functional abnormalities as well as the structure-function interrelation in several SZ-related brain regions.

Cognitive capacity similarly predicts insight into symptoms in first- and multiple-episode psychosis

BACKGROUND

Lack of insight is a frequent characteristic of psychotic disorders, both in patients who recently experienced a first episode of psychosis (FEP) and those who experience recurrent multiple episodes (MEP). Insight is a multifaceted construct: its clinical form notably includes the unawareness of being ill, of symptoms, and of the need for treatment. Cognitive capacity is among the key determinants of insight into symptoms, but less is known about whether stage of illness (FEP vs. MEP) moderates this association.

METHODS

Our aim is to evaluate the association between cognitive capacity and symptom unawareness using structural equation modeling and moderated multiple regression. A total of 193 FEP and MEP patients were assessed using the CogState battery and the Scale to Assess Unawareness of Mental Disorder.

RESULTS

Analyses suggest that cognitive capacity accounts for a relatively small proportion of the total variation in symptom unawareness (6.4%). There was no evidence to suggest a moderating effect of stage of illness on this association.

CONCLUSIONS

The effect of general cognitive capacity on symptom unawareness is relatively small, and this basic relation was unrelated to stage of illness. It is possible that stage of illness could moderate this association only for certain facets of insight not assessed in this study (e.g., unawareness of the need for treatment).

NMDA Receptor Model of Antipsychotic Drug-Induced Hypofrontality

Schizophrenia is a chronic mental disease, affecting around 1% of the general population. Schizophrenia is characterized by productive, negative, affective, and disorganization symptoms, and cognitive deficits. Cognitive deficits prevail in most of the schizophrenia patients and are one of the most disabling symptoms. They usually occur before the acute episode of the disease and tend to become chronic with no satisfactory treatment from antipsychotic drugs. Because of their early manifestation in patients’ lives, cognitive deficits are suggested to be the primary symptom of schizophrenia. The pathogenesis of cognitive deficits in schizophrenia is not fully understood. They are linked with hypofrontality, which is a decrease in blood flow and glucose metabolism in the prefrontal lobe of schizophrenia-suffering patients. Hypofrontality is linked with disturbances of the corticolimbothalamic circuit, important for cognition and memory in humans. The circuit consists of a group of neuroanatomic structures and hypothetically any disturbance in them may result in cognitive deficits. We present a translational preclinical model of understanding how antipsychotic medication may decrease the N-methyl-D-aspartic acid (NMDA) receptors’ activity and produce dysfunctions in the corticolimbothalamic circuit and hypofrontality. From several pharmacological experiments on rats, including mainly our own recent findings, we collected data that suggest that antipsychotic medication may maintain and escalate hypofrontality in schizophrenia, decreasing NMDA receptor activity in the corticolimbothalamic circuit in the human brain. We discuss our findings within the literature of the subject.

Early Substance Use Cessation Improves Cognition-10 Years Outcome in First-Episode Psychosis Patients

Background: Cognitive impairment may be a risk factor for, as well as a consequence of, psychosis. Non-remitting symptoms, premorbid functioning, level of education, and socioeconomic background are known correlates. A possible confounder of these associations is substance use, which is common among patients with psychosis and linked to worse clinical outcomes. Studies however show mixed results for the effect of substance use on cognitive outcomes. In this study, the long-term associations of substance use with cognition in a representative sample of first-episode psychosis patients were examined. Methods: The sample consisted of 195 patients. They were assessed for symptom levels, function, and neurocognition at 1, 2, 5, and 10 years after first treatment. Test scores were grouped into factor analysis-based indices: motor speed, verbal learning, visuomotor processing, verbal fluency, and executive functioning. A standardized composite score of all tests was also used. Patients were divided into four groups based on substance-use patterns during the first 2 years of treatment: persistent users, episodic users, stop-users, and nonusers. Data were analyzed using linear mixed effects modeling. Results: Gender, premorbid academic functioning, and previous education were the strongest predictors of cognitive trajectories. However, on motor speed and verbal learning indices, patients who stopped using substances within the first 2 years of follow-up improved over time, whereas the other groups did not. For verbal fluency, the longitudinal course was parallel for all four groups, while patients who stopped using substances demonstrated superior performances compared with nonusers. Persistent users demonstrated impaired visuomotor processing speed compared with nonusers. Within the stop- and episodic use groups, patients with narrow schizophrenia diagnoses performed worse compared with patients with other diagnoses on verbal learning and on the overall composite neurocognitive index. Discussion: This study is one of very few long-term studies on cognitive impairments in first-episode psychosis focusing explicitly on substance use. Early cessation of substance use was associated with less cognitive impairment and some improvement over time on some cognitive measures, indicating a milder illness course and superior cognitive reserves to draw from in recovering from psychosis.

Comparing cognitive clusters across first- and multiple-episode of psychosis

Cognitive impairments in psychotic disorders (PD) present heterogeneously across patients. Between 2 and 5 clusters have been identified in previous studies with first-episode (FEP) and multiple-episodes of psychosis (MEP) patients suggesting different profiles of impairment. Past findings suggest there are differences between FEP and MEP patients regarding severity and number of affected cognitive domains. Heterogeneity of cognitive deficits in PD has perhaps hindered our understanding of their course. The present study compared non-affective FEP and MEP patients to assess whether illness chronicity could influence cognitive impairment profiles. We analyzed cognitive data, collected with the Cogstate Schizophrenia Battery, of FEP and MEP patients using cluster analysis. We compared clustering methods to obtain a more robust solution. For FEP patients, data were collected at their entry to a specialized clinic; the MEP group consisted of in- and outpatients. Results suggested cognitive heterogeneity was similar in FEP and MEP samples, although in different proportions. Three clusters were identified as the most stable solution and comprised groups of patients with either 1- no cognitive impairment (over-representation of FEP), 2- generalized deficits (over-representation of MEP), or 3- intermediate impairments. These findings encourage early interventions adapted to the profile of impairment.

Individual trajectories of cognitive performance in first episode psychosis: a 2-year follow-up study

Individual changes over time in cognition in patients with psychotic disorders have been studied very little, especially in the case of first episode psychosis (FEP). We aimed to establish whether change in individual trajectories in cognition over 2 years of a sample of 159 FEP patients was reliable and clinically significant, using the reliable change index (RCI) and clinically significant change (CSC) methods. We also studied a sample of 151 matched healthy controls. Patients and controls were assessed with a set of neuropsychological tests, as well as premorbid, clinical and functionality measures. We analysed the course of cognitive measures over time, using analysis of variance, and the individual trajectories in the cognitive measures with the regression-based RCI (RCI_SRB) and the CSC. The RCI_SRB showed that between 5.4 and 31.2% of the patients showed deterioration patterns, and between 0.6 and 8.8% showed improvement patterns in these tests over time. Patients showing better cognitive profiles according to RCI_SRB (worsening in zero to two cognitive measures) showed better premorbid, clinical and functional profiles than patients showing deterioration patterns in more than three tests. When combining RCI_SRB and CSC values, we found that less than 10% of patients showed improvement or deterioration patterns in executive function and attention measures. These results support the view that cognitive impairments are stable over the first 2 years of illness, but also that the analysis of individual trajectories could help to identify a subgroup of patients with particular phenotypes, who may require specific interventions.

The research evidence for schizophrenia as a neurodevelopmental disorder

Schizophrenia is a neurodevelopmental disorder that starts very early. In this review we describe the empirical evidence for the neurodevelopmental model. First, by outlining the roots of psychological research that laid the foundation of the model. Thereafter, describing cognitive dysfunction observed in schizophrenia, and the course of cognitive functioning in the illness. Then, research findings that speak for and studies that speak against the view that schizophrenia is a degenerative process is discussed. We find that there is ample evidence that cognitive disturbance is a core element in schizophrenia. However, we have limited understanding of what initiates the abnormal development. This the paper ends with pointing out some of the factors that may trigger the deviant neurocognitive development in schizophrenia.

Do clinical characteristics predict the cognitive course in early-onset schizophrenia-spectrum disorders?

BACKGROUND

Being in a period with extensive brain maturation, adolescents with early-onset schizophrenia-spectrum disorders (EOS) provide unique neurodevelopmental data that may contribute to a better understanding of schizophrenia at all ages. Cognitive dysfunction is a central feature of schizophrenia and is more pronounced in EOS than in later onset illness. However, there is limited research on both the long-term course of global cognition in EOS, and how cognition over time is influenced by clinical characteristics during the early illness period.

METHODS

Thirty-one EOS patients and 73 controls (age 12-18) were assessed on clinical variables at baseline (PANSS, duration of untreated psychosis [DUP], hospitalizations, suicide attempts, and remission). Neuropsychological assessments with the MATRICS Consensus Cognitive Battery (MCCB) were conducted at baseline and after both 1 and 2 years, and composite scores of total performances were calculated. The analyses were performed with a linear mixed model.

RESULTS

The present study found that global cognition followed a stable course over the first years of the disease in EOS, though at a significantly lower level in EOS compared with the controls. We did not detect a relationship between DUP, remission, positive/negative symptoms, and hospitalizations on one hand, and long-term cognition on the other hand, but PANSS-general and suicide attempt history at baseline were identified as risk factors of longitudinal cognitive function.

CONCLUSIONS

Though at different levels, the EOS group and the controls had a similar cognitive course over 2 years. Some baseline characteristics (psychotic symptoms, DUP, remission, and hospitalization) had no influence on cognition within the first 2 years of illness. In contrast, general symptoms and a history of suicide attempts at baseline were more potent risk factors of the cognitive course than the psychotic-specific symptoms, and should, therefore, be subject to specific attention in the evaluation and treatment of patients with early-onset psychosis.

Associations between cognition and internalizing problems in young adults with early-onset schizophrenia: A 13-year follow-up study

The present follow-up study examines the associations between cognition and parent-rated internalizing problems among adolescents with early-onset schizophrenia (EOS) at baseline (T1) and self-rated internalizing problems 13 years later (T2). Twelve individuals (8 male/4 female) with EOS and 30 healthy controls (16 male/14 female) were included in the study. All were between 12 and 18 years of age at T1. Internalizing problems were measured with the Achenbach System of Empirically Based Assessment Internalizing Scale. Cognition was examined with a neuropsychological test battery measuring auditory attention/working memory, visuomotor processing, cognitive flexibility and verbal memory. Compared to healthy controls, the EOS group had significant cognitive deficits and more internalizing problems both at T1 and T2. There was no correlation between parent-rated internalizing problems at T1 and self-rated internalizing problems at T2 in the EOS group. However, deficits in auditory attention/working memory at T1 were significantly associated with internalizing problems at T2. A focus on improving the treatment of cognitive impairments may be important in preventing the development of internalizing problems in young patients with schizophrenia. The small sample size of the study is a limitation and further research is recommended.

Overlapping and disease specific trait, response, and reflection impulsivity in adolescents with first-episode schizophrenia spectrum disorders or attention-deficit/hyperactivity disorder

BACKGROUND

Schizophrenia and attention-deficit/hyperactivity disorder (ADHD) are developmental disorders with shared clinical characteristics such as cognitive impairments and impulsivity. Impulsivity is a core feature of ADHD and an important factor in aggression, violence, and substance use in schizophrenia. Based on the hypothesis that schizophrenia and ADHD represent a continuum of neurodevelopmental impairments, the aim was to identify overlapping and disease specific forms of impulsivity.

METHODS

Adolescents between 12 and 17 years of age were assessed with the Schedule for Affective Disorders and Schizophrenia for School-aged Children - Present and Lifetime Version. Subjects with early-onset, first-episode schizophrenia spectrum disorders (EOS) (N = 29) or ADHD (N = 29) and healthy controls (N = 45) were compared on two performance measures (Information Sampling Task, Stop Signal Task) and a subjective personality trait measure of impulsivity (Barratt Impulsiveness Scale, Version 11 (BIS-11)).

RESULTS

Significantly increased reflection impulsivity was observed in ADHD but not in the EOS group. No significant response inhibition deficits (stop signal reaction time) were found in the two clinical groups. The ADHD and the EOS group showed significantly increased motor, attentional, and non-planning subtraits of impulsivity.

CONCLUSIONS

Impaired pre-decisional information gathering appeared to be specific for ADHD while the information gathering was not significantly reduced in subjects with EOS. Neither the ADHD nor EOS group showed impaired response inhibition but shared increased personality subtraits of attentional, non-planning, and motor impulsivity although the latter was significantly more pronounced in ADHD. These increased subtraits of impulsivity may reflect diagnostic non-specific neurodevelopmental impairments in ADHD and EOS in adolescence.

Amendment of traditional assessment measures for the negative symptoms of schizophrenia

Schizophrenia research based on traditional assessment measures for negative symptoms appears to be, to some extent, unreliable. The limitations of the Positive and Negative Syndrome Scale (PANSS) and the Scale for the Assessment of Negative Symptoms (SANS) have been extensively acknowledged and should be taken into account. The aim of this study is to show how the PANSS and the SANS conflate negative symptoms and cognition and to offer alternatives for the limitations found.

METHODS

A sample of 117 participants with schizophrenia from two independent studies was retrospectively investigated. Linear regression models were computed to explore the effect of negative symptoms and illness duration as predictors of cognitive performance.

RESULTS

For the PANSS, the item "abstract thinking" accounted for the association between negative symptoms and cognition. For the SANS, the "attention" subscale predicted the performance in verbal memory, but illness duration emerged as a stronger predictor than negative symptoms for outcomes of processing speed, verbal and working memory.

CONCLUSION

Utilizing alternative models to the traditional PANSS and SANS formats, and accounting for illness duration, provide more precise evidence on the relationship between negative symptoms and cognition. Since these measures are still extensively utilized, we recommend adopting more rigorous approaches to avoid misleading results.

A Comparison of Methamphetamine-Induced Psychosis and Schizophrenia: A Review of Positive, Negative, and Cognitive Symptomatology

Methamphetamine is a potent psychostimulant that can induce psychosis among recreational and chronic users, with some users developing a persistent psychotic syndrome that shows similarities to schizophrenia. This review provides a comprehensive critique of research that has directly compared schizophrenia with acute and chronic METH psychosis, with particular focus on psychiatric and neurocognitive symptomatology. We conclude that while there is considerable overlap in the behavioral and cognitive symptoms between METH psychosis and schizophrenia, there appears to be some evidence that suggests there are divergent aspects to each condition, particularly with acute METH psychosis. Schizophrenia appears to be associated with pronounced thought disorder, negative symptoms more generally and cognitive deficits mediated by the parietal cortex, such as difficulties with selective visual attention, while visual and tactile hallucinations appear to be more prevalent in acute METH-induced psychosis. As such, acute METH psychosis may represent a distinct psychotic disorder to schizophrenia and could be clinically distinguished from a primary psychotic disorder based on the aforementioned behavioral and cognitive sequelae. Preliminary evidence, on the other hand, suggests that chronic METH psychosis may be clinically similar to that of primary psychotic disorders, particularly with respect to positive and cognitive symptomatology, although negative symptoms appear to be more pronounced in schizophrenia. Limitations of the literature and avenues for future research are also discussed.

Measuring stability of cognitive impairment in inpatients with schizophrenia with alternate forms of the Montreal Cognitive Assessment during acute hospitalization

Cognitive impairment is a core feature of schizophrenia. Measuring the stability of cognitive impairment is important for further understanding of this disorder. The Montreal Cognitive Assessment (MoCA) has been demonstrated to be a brief and effective screening tool in detecting cognitive impairment in patients with schizophrenia. It has alternative versions designed for longitudinal settings. The current study retrospectively analyzed the total and subscores of two versions of the MoCA, administered to a group of inpatients with severe schizophrenia at admission and discharge, to measure their cognitive stability during hospitalization. The results revealed that the test-retest reliability coefficient of the MoCA had good reliability, suggesting the two alternative versions of the MoCA are reliable measurements for assessing cognitive impairment repeatedly in patients with schizophrenia. The paired-samples t-test showed that the overall cognitive impairment of patients measured by two forms of the MoCA remained stable during acute hospital stay and across symptom changes. Furthermore, the results showed that patients' cognitive stability was not related to their symptom/illness severity improvement, age, education, or length of stay.

Long-Term Memory Performance in Adult ADHD

OBJECTIVE

Memory problems are a frequently reported symptom in adult ADHD, and it is well-documented that adults with ADHD perform poorly on long-term memory tests. However, the cause of this effect is still controversial. The present meta-analysis examined underlying mechanisms that may lead to long-term memory impairments in adult ADHD.

METHOD

We performed separate meta-analyses of measures of memory acquisition and long-term memory using both verbal and visual memory tests. In addition, the influence of potential moderator variables was examined.

RESULTS

Adults with ADHD performed significantly worse than controls on verbal but not on visual long-term memory and memory acquisition subtests. The long-term memory deficit was strongly statistically related to the memory acquisition deficit. In contrast, no retrieval problems were observable.

CONCLUSION

Our results suggest that memory deficits in adult ADHD reflect a learning deficit induced at the stage of encoding. Implications for clinical and research settings are presented.

Β-Amyloid Burden is Not Associated with Cognitive Impairment in Schizophrenia: A Systematic Review

Current literature suggests that the pathology of schizophrenia (SCZ) has developmental origins. However, the neurodevelopmental theory of SCZ cannot solely explain progressive neurodegenerative processes in the illness. There is evidence of accelerated cognitive decline and increased risk of dementia in elderly patients with SCZ. Investigating β-amyloid (Aβ), we conducted a systematic review focusing on Aβ in patients with SCZ. An OVID literature search using PsychINFO, Medline, and Embase databases was conducted, looking for studies that compared Aβ levels between patients with SCZ and either elderly control subjects, patients with Alzheimer disease (AD), or patients with other psychiatric illnesses. Among 14 identified studies, 11 compared Aβ between SCZ and elderly control subjects, 7 between SCZ and AD, and 3 between SCZ and other psychiatric illnesses. As a result, no evidence was found suggesting that Aβ levels differ in patients with SCZ from elderly control subjects or patients with other psychiatric illnesses. All seven studies reported lower cortical Aβ in patients with SCZ than patients with AD. Furthermore, three of the four studies, which investigated the relationship between Aβ and cognitive impairment in SCZ, observed no association between two factors. The limitations of the included studies are small sample sizes, the inclusion of cerebrospinal fluid Aβ or postmortem plaques rather than cortical Aβ assessment in vivo, and the investigation of different brain regions. In conclusion, Aβ deposition is not associated with cognitive decline in late-life SCZ. Future studies should investigate other neurodegenerative indicators in SCZ to better understand the pathophysiologic mechanisms underlying this illness.

Cognitive impairments in first-episode drug-naive and chronic medicated schizophrenia: MATRICS consensus cognitive battery in a Chinese Han population

Cognitive deficits are a core feature of schizophrenia and we examined the cognitive profile of first-episode and chronic schizophrenia in a Chinese Han population using the MATRICS Consensus Cognitive Battery (MCCB). We recruited 79 first-episode drug-naïve (FEDN) schizophrenia, 132 chronic medicated schizophrenia inpatients and 124 healthy controls. We assessed patient psychopathology using the Positive and Negative Syndrome Scale (PANSS). MCCB total score (p<0.01) and index scores of category fluency, trail making A, digital sequence, Hopkins Verbal Learning Test (HVLT), mazes, and Mayer-Salovey-Caruso Emotional Intelligence Test (MSCEIT) were significantly higher in FEDN than in chronic patients (all p<0.05). FEDN exhibited relative weakness in continuous performance, whereas chronic patients exhibited relative weakness in mazes. Multiple regression analysis confirmed that in FEDN and chronic patients, total score and negative symptom of PANSS were independent contributors to MCCB total score, respectively. Our results not only demonstrate the applicability of the MCCB as a sensitive measure of cognitive impairment for schizophrenia patients in a Chinese Han population, but also suggest that the compromised cognition is present in the early stage of schizophrenia, some of which could be more severe in the chronic stage of illness.

Neurocognition and Duration of Psychosis: A 10-year Follow-up of First-Episode Patients

A substantial proportion of schizophrenia-spectrum patients exhibit a cognitive impairment at illness onset. However, the long-term course of neurocognition and a possible neurotoxic effect of time spent in active psychosis, is a topic of controversy. Furthermore, it is of importance to find out what predicts the long-term course of neurocognition. Duration of untreated psychosis (DUP), accumulated time in psychosis the first year after start of treatment, relapse rates and symptoms are potential predictors of the long-term course. In this study, 261 first-episode psychosis patients were assessed neuropsychologically on one or more occasions. Patients were tested after remission of psychotic symptoms and reassessed 1, 2, 5, and 10 years after inclusion. The neurocognitive battery consisted of California Verbal Learning Test, Wisconsin Card Sorting Test, Controlled Oral Word Association Task, Trail Making A and B, and Finger Tapping. We calculated a composite score by adding the z-scores of 4 tests that were only moderately inter-correlated, not including Finger Tapping. Data were analyzed by a linear mixed model. The composite score was stable over 10 years. No significant relationship between psychosis before (DUP) or after start of treatment and the composite score was found, providing no support for the neurotoxicity hypothesis, and indicating that psychosis before start of treatment has no significant impact on the course and outcome in psychosis. We found no association between symptoms and the neurocognitive trajectory. Stable remission during the first year predicted neurocognitive functioning, suggesting that the early clinical course is a good predictor for the long-term course.

Cognitive course in first-episode psychosis and clinical correlates: A 4 year longitudinal study using the MATRICS Consensus Cognitive Battery

While cognitive impairments are prevalent in first-episode psychosis, the course of these deficits is not fully understood. Most deficits appear to remain stable, however there is uncertainty regarding the trajectory of specific cognitive domains after illness onset. This study investigates the longitudinal course of cognitive deficits four years after a first-episode of psychosis and the relationship of performance with clinical course and response to treatment. Twenty three individuals with psychotic illness, matched with 21 healthy volunteers, were assessed using the MATRICS Consensus Cognitive Battery at illness onset and 4 years later. We also investigated the relationship between cognitive deficits and quality of life and clinical indices. Verbal learning and two measures of processing speed had marked poorer trajectory over four years compared to the remaining cognitive domains. Processing speed performance was found to contribute to the cognitive deficits in psychosis. Poorer clinical outcome was associated with greater deficits at illness onset in reasoning and problem solving and social cognition. Cognitive deficits did not predict quality of life at follow-up, nor did diagnosis subtype differentiate cognitive performance. In conclusion, an initial psychotic episode may be associated with an additional cost on verbal learning and two measures of processing speed over a time spanning at least four years. Moreover, processing speed, which has been manipulated through intervention in previous studies, may represent a viable therapeutic target. Finally, cognition at illness onset may have a predictive capability of illness course.

The 4th Schizophrenia International Research Society Conference, 5-9 April 2014, Florence, Italy: a summary of topics and trends

The 4th Schizophrenia International Research Society Conference was held in Florence, Italy, April 5-9, 2014 and this year had as its emphasis, "Fostering Collaboration in Schizophrenia Research". Student travel awardees served as rapporteurs for each oral session, summarized the important contributions of each session and then each report was integrated into a final summary of data discussed at the entire conference by topic. It is hoped that by combining data from different presentations, patterns of interest will emerge and thus lead to new progress for the future. In addition, the following report provides an overview of the conference for those who were present, but could not participate in all sessions, and those who did not have the opportunity to attend, but who would be interested in an update on current investigations ongoing in the field of schizophrenia research.

Relative stability of neurocognitive deficits in early onset schizophrenia spectrum patients

In contrast to the findings of progressive structural brain changes in adolescence, longitudinal studies of patients with early onset schizophrenia spectrum disorders (EOS) indicate that neurocognitive deficits are relatively stable over the first years. The aim of this study is to assess neurocognitive functions longitudinally in patients with EOS compared to healthy controls (HC) using the MATRICS Cognitive Consensus Battery (MCCB).

METHODS

Twenty patients with EOS and 41 HC were tested with the MCCB at baseline (T1) and after one (T2) and two years (T3). The mean age for the EOS group was 15.6 (SD=1.8) years, while the mean duration of illness was 1.7 (SD=1.4) years at T1.

RESULTS

The EOS group's neurocognitive performances indicate a stable deficit on most measures. Both the EOS and HC groups showed improved neurocognitive functioning over time on all measures except for the verbal learning domain. There was an interaction between the EOS and HC groups' performance over time on the Trail Making Test A (TMA), a subtest on the processing speed domain.

CONCLUSION

The longitudinal neurocognitive performances measured by the MCCB confirm previous findings of stable deficits in patients with EOS. It is premature to conclude whether the increases in neurocognitive performance reflect developmental processes in adolescence or may be explained by learning effects, or both. As opposed to the other tests in this domain, a stagnation in processing speed as measured by the TMA suggests that the TMA is a particularly sensitive measure of neurodevelopmental deviance in EOS.

Neuropsychological functioning in childhood-onset psychosis and attention-deficit/hyperactivity disorder

BACKGROUND

Attention-deficit/hyperactivity disorder (ADHD) and childhood-onset psychosis (COP) are chronic, heterogeneous disorders with symptoms that frequently co-occur, but the etiology of their comorbidity is unknown. Studies of each disorder indicate that both ADHD and COP are associated with a range of neuropsychological weaknesses, but few neuropsychological studies have directly compared groups with ADHD and COP.

METHODS

Groups with ADHD only (32 F, 48 M), COP only (5 F, 5 M), ADHD + COP (9 F, 21 M), and a control group with neither disorder (25 F, 44 M) completed a neuropsychological battery that included measures of verbal working memory, response inhibition, response speed and variability, and selective attention.

RESULTS

All three clinical groups exhibited significantly lower performance versus the control group on all neuropsychological measures, whereas the only significant difference between the clinical groups was a significantly larger weakness in verbal working memory in the groups with COP.

CONCLUSIONS

The frequent co-occurrence between COP and ADHD may reflect shared neuropsychological weaknesses that are most pronounced on measures of working memory and response variability.

Working memory arrest in children with high-functioning autism compared to children with attention-deficit/hyperactivity disorder: results from a 2-year longitudinal study

The aim of this study was to analyse the development of verbal working memory in children with high-functioning autism compared to children with attention-deficit/hyperactivity disorder and typically developing children. A total of 34 children with high-functioning autism, 72 children with attention-deficit/hyperactivity disorder and 45 typically developing children (age 9-16 years) were included at baseline and followed up approximately 25 months later. The children were given a letter/number sequencing task to assess verbal working memory. The performance of children with high-functioning autism on verbal working memory did not improve after 2 years, while improvement was observed in children with attention-deficit/hyperactivity disorder and typically developing children. The results indicate a different developmental trajectory for verbal working memory in children with high-functioning autism compared to children with attention-deficit/hyperactivity disorder and typically developing children. More research is needed to construct a developmental framework more suitable for children with autism spectrum disorder.

Ten year neurocognitive trajectories in first-episode psychosis

Objective: Neurocognitive impairment is commonly reported at onset of psychotic disorders. However, the long-term neurocognitive course remains largely uninvestigated in first episode psychosis (FEP) and the relationship to clinically significant subgroups even more so. We report 10 year longitudinal neurocognitive development in a sample of FEP patients, and explore whether the trajectories of cognitive course are related to presence of relapse to psychosis, especially within the first year, with a focus on the course of verbal memory.

Method: Forty-three FEP subjects (51% male, 28 ± 9 years) were followed-up neurocognitively over five assessments spanning 10 years. The test battery was divided into four neurocognitive indices; Executive Function, Verbal Learning, Motor Speed, and Verbal Fluency. The sample was grouped into those relapsing or not within the first, second and fifth year.

Results: The four neurocognitive indices showed overall stability over the 10 year period. Significant relapse by index interactions were found for all indices except Executive Function. Follow-up analyses identified a larger significant decrease over time for the encoding measure within Verbal Memory for patients with psychotic relapse in the first year [F_{(4, 38)} = 5.8, p = 0.001, η² = 0.40].

Conclusions: Main findings are long-term stability in neurocognitive functioning in FEP patients, with the exception of verbal memory in patients with psychotic relapse or non-remission early in the course of illness. We conclude that worsening of specific parts of cognitive function may be expected for patients with on-going psychosis, but that the majority of patients do not show significant change in cognitive performance during the first 10 years after being diagnosed.

Neurocognition in early-onset schizophrenia

Cognitive impairment is recognized as a central feature of schizophrenia. Early-onset schizophrenia (EOS) represents a more severe variant of the disorder associated with onset in childhood or adolescence. Examination of the cognitive abnormalities of EOS offers the opportunity to explore how disease-related mechanisms may affect facets of cognitive development. This article summarizes and synthesizes available data with regards to the profile of cognitive impairments in EOS, their severity, and their evolution over the course of the disorder.

Course of cognitive deficits in first episode of non-affective psychosis: a 3-year follow-up study

Cognitive dysfunctions are critical determinants of the quality of life and functionality in schizophrenia. Whether the cognitive deficits present at an early stage, are static or change across one's lifespan is still under debate. This study aims to investigate the long-term (3 years) course of cognitive deficits in a large and representative cohort of first episode schizophrenia spectrum patients (N=155),and evaluate their influence on disability. In addition, a healthy control sample (N=43) was also studied for comparison. This study evaluates the performance of patients and controls in a battery of cognitive assessments using baseline, 1-year and 3-year follow-up designs. The results show that, although cognitively outperformed by the controls at any time, the cognitive performance of the patients improved similar to the controls in all cognitive functions except verbal and visual memory. Even though the course of cognitive performance across the sample as a whole was stable, the subgroup of patients who experienced a cognitive decline had worse functionality and lesser amelioration of negative symptoms. Overall, there is no significant deterioration in the cognitive function in a group of first episode schizophrenia spectrum disorder patients, with the possible exception of tasks that were associated with episodic memory. However, patients whose cognitive performance demonstrated a declining trend may present with a poorer progression in terms of clinical and disability variables.

Neurocognitive development in first episode psychosis 5 years follow-up: associations between illness severity and cognitive course

Cognitive deficits are documented in first-episode psychosis (FEP), but the continuing course is not fully understood. The present study examines the longitudinal development of neurocognitive function in a five year follow-up of FEP-patients, focusing on the relation to illness severity, as measured by relapses and diagnostic subgroups. The study is an extension of previous findings from the TIPS-project, reporting stability over the first two years. Sixty-two FEP patients (53% male, age 28 ± 9 years) were neuropsychologically examined at baseline and at 1, 2, and 5 year follow-ups. The test battery was divided into five indices; Verbal Learning, Executive Function, Impulsivity, Motor Speed, and Working Memory. To investigate the effect of illness severity, the sample was divided in groups based on number of relapses, and diagnostic subgroups, respectively. Impulsivity and Working Memory improved significantly in the first two years, followed by no change over the next three years. Motor Speed decreased significantly from 2 to 5 years. Number of relapses was significantly related to Verbal Learning and Working Memory, showing a small decrease and less improvement, respectively, in patients with two or more episodes. No significant association was found with diagnostic group. Neurocognitive stability as well as change was found in a sample of FEP-patients examined repeatedly over 5 years. Of potential greater importance for understanding how psychotic illnesses progress, is the finding of significant associations between neurocognition and number of relapses but not diagnostic group, indicating that neurocognition is more related to recurring psychotic episodes than to the descriptive diagnosis per se.

Executive function in early- and adult onset schizophrenia

BACKGROUND

The goal of this study was to investigate differences in executive functioning between patients with early-onset and adult-onset schizophrenia spectrum psychoses at the time of first treatment.

METHODS

Neuropsychological tests covering executive functioning domains were performed for 20 adolescents with early-onset schizophrenia (EOS) close to first treatment and 90 first episode patients with adult onset schizophrenia (AOS) in addition to 66 adolescent- and 127 adult age and gender matched healthy controls.

RESULTS

Both EOS and AOS patients had significantly poorer executive performance than their age- and gender matched healthy counterparts. Both healthy adolescent controls and EOS patients had poorer executive performance than their adult counterparts. However, there were no differences in executive functioning between EOS and AOS patients after controlling for the levels of their age matched healthy control groups. Substituting EOS/AOS status with other age-at-onset thresholds had no effect.

CONCLUSIONS

We find the same relative levels of executive dysfunction in EOS- and AOS groups at the time of first treatment. This does not necessarily contradict previous findings of more severe dysfunction in EOS patients over time, but indicates an interaction between the disorder and the maturational processes that only can be investigated through longitudinal studies.

Processing speed and neurodevelopment in adolescent-onset psychosis: cognitive slowing predicts social function

Onset of psychosis may be associated with abnormal adolescent neurodevelopment. Here we examined the neurocognitive profile of first-episode, adolescent onset psychosis (AOP) as compared to typically developing adolescents, and asked whether neurocognitive performance varied differentially as a function of age in the cases compared with controls. A comprehensive neuropsychological battery was administered to 35 patients experiencing a first-episode of a DSM-IV psychotic disorder and to 31 matched controls. Clinicians also rated subjects' social and role functioning, both at the time of neuropsychological assessment and 1 year later. Although patients displayed a wide range of impairments relative to controls, their most pronounced deficits included verbal memory, sensorimotor dexterity and cognitive processing speed. Among these, only processing speed showed a significant group-by-age interaction, consistent with an aberrant developmental course among AOP patients. Processing speed also accounted for substantial variance in other areas of deficit, and predicted social functioning 1 year later. AOP patients fail to show normal age-related increases in processing speed, which in turn predicts poorer functional outcomes. This pattern is consistent with the view that adolescent brain developmental processes, such as myelination, may be disrupted in these patients.

Processing speed and executive functions predict real-world everyday living skills in adolescents with early-onset schizophrenia

Cognition and clinical variables are known to be among the most predictive factors of real-world social functioning and daily living skills in adult-onset schizophrenia. Fewer studies have focused on their impact in adolescents with early-onset schizophrenia (EOS). The aim of this study is to examine the relationships and the predictive value of cognition and clinical variables on real-world daily living skills in a sample of adolescents with EOS. Cognitive, clinical and real-world everyday living skills measures were administered to 45 clinically and pharmacologically stabilized adolescent outpatients with EOS and 45 healthy control subjects matched by age and sex. Multi-variant analyses to compare cognitive and real-world functioning profiles between patients and controls and regression analysis to identify predictors of real-world functioning scores in patients were used. Adolescents with EOS showed a generalized cognitive and real-world daily living skills dysfunction. Several cognitive and clinical variables significantly correlated with real-world daily living skills functioning but only the processing speed and executive functions emerged as independent predictors of everyday living skills scores, explaining 25.1% of the variance. Slowness in processing information and executive dysfunction showed a significant impact on real-world daily living skills in EOS, independently from clinical symptoms and other cognitive variables. Nevertheless, much of the variance in the daily living skills measure remained unaccounted for, suggesting that other factors were involved as well in this young population.

Executive function tests in early-onset psychosis: which one to choose?

People with schizophrenia exhibit executive functioning deficits, an area well investigated in the adult onset schizophrenia (AOS) group, but far less so in early-onset schizophrenia (EOS). Since EOS in general seems to exhibit poorer cognitive functions and is clinically more compromised than AOS, choice of efficient and sensitive assessment measures is not necessarily the same within the two groups. The MATRICS Consensus Cognitive Battery was developed for adults when studying treatment effects and uses Mazes (Neuropsychological Assessment Battery [NAB]) to assess executive functioning. We tested 31 adolescents with schizophrenia spectrum disorders and 66 healthy controls in order to examine how Mazes compares to two other commonly used tests to measure executive functioning, D-KEFS Color Word Interference Test (Stroop) and the Wisconsin Card Sorting Test (WCST). Significant discriminating power was found for all three measures. Patients performed 0.8-1.5 SD below controls with Stroop as the most sensitive measure, followed by Mazes and WCST. Mazes was selected by the MATRICS to assess treatment effects in AOS and is shown to be able. We find the instrument also able to separate adolescent patients from controls and thus, it appears a sensible choice in clinical settings. If a more elaborated neuropsychological evaluation of the executive functioning domain is needed, Stroop should be considered a complementary test.

Level and pattern of neuropsychological functioning in early-onset psychoses

The present study aimed to compare the level and pattern of cognitive deficits in patients with early-onset psychoses with an age, gender and IQ matched control group. In order to ensure a representative sample of patients with psychoses, participants with an IQ of less than 70 were included. Forty-eight patients with an onset of psychoses before the age of 16, and 47 age, gender and IQ matched controls without psychoses were recruited. Psychotic symptomatology was assessed using the Schedules for Clinical Assessment to obtain DSM-IV and ICD-10 diagnoses. Positive and negative symptoms were assessed using the Positive and Negative Symptoms Scale. Levels of cognitive function were measured using a comprehensive neuropsychological battery. A pattern of specific impairments was not found, with few significant differences between the two cohorts. However both cohort groups performed lower than age derived norms. Therefore it appears that there are global cognitive deficits rather than specific deficits in early-onset psychoses when compared to normative data, in-line with conclusions of early-onset schizophrenia research, but patients did not have greater deficit than controls when matched on IQ, gender and age, even after excluding participants with IQ less than 70.

Event-related potentials in patients with adult attention-deficit/hyperactivity disorder versus schizophrenia

Event-related potentials (ERPs) such as Nd, N2b, and P300 in an attentional task and an auditory oddball task were compared among 54 adult AD/HD patients, 43 schizophrenic patients (SZ), and 40 healthy age-matched volunteers (HC). It is known that Nd, N2b, and P300 reflect selective attention, voluntary attention, and cognitive context updating respectively. The peak amplitude of P300 was significantly lower in the adult AD/HD and SZ groups than in the HC group. The peak latencies of late Nd, N2b, and P300 were significantly longer in the SZ group than in the HC and adult AD/HD groups. Thus, attenuated amplitude and prolonged latency of various ERP components in the SZ group suggest the possibility of impairment of basic mechanisms underlying cognitive processing. Unlike the SZ group, the adult AD/HD group exhibited reduced amplitude of P300 but not prolonged latency. These findings suggest the existence of a different type of cognitive dysfunction in the adult AD/HD group, which might be closely related to attentional function.

Deficient maturation of aspects of attention and executive functions in early onset schizophrenia

The few existing long-term, neuropsychological follow-up studies of early onset schizophrenia (EOS) patients have reported relative stability in some cognitive functions but abnormal developmental trajectories in verbal memory, set shifting, aspects of attention, and speed of information processing throughout late adolescence into early adulthood. The current 5-year follow-up study compared the development of specific cognitive functions in EOS patients (N = 17) from the time of first-episode to chronic phase with that of healthy controls (N = 38) and secondarily to patients with other early onset, non-organic, non-affective psychoses (EOP) (N = 11). Speed of processing of executive functions, set shifting, and attention improved significantly in the healthy controls and reflected continuous functional maturation during late adolescence and early adulthood. The developmental progression of attention and set shifting but not speed of processing of executive functions was significantly subnormal in EOS patients. Other specific cognitive functions that had attained functional maturity in the healthy controls before or around the time of the baseline assessment showed normal development in EOS patients during the follow-up period, indicating stable cognitive deficits. These results suggest post-onset developmental deficits in two out of the three aspects of attention and executive functions that have protracted maturational trajectories and that overlap the age of onset of EOS. No significant difference in the development of any specific cognitive function was found between the EOS and EOP group.

Cognitive function in early onset schizophrenia: a selective review

Schizophrenia is widely regarded as the clinical outcome of aberrant neurodevelopment caused by a combination of genetic and non-genetic factors. Early Onset Schizophrenia (EOS) manifests in childhood or adolescence and represents a more severe variant of the Adult Onset form of the disorder (AOS). EOS offers a unique opportunity of exploring the impact of disease related mechanisms on the developmental trajectory of cognitive function. The present review focused on the domains of general intellectual ability (IQ), attention, executive function and memory. Significant methodological variability was noted across the different studies that examined these aspects of cognition in EOS patients. Despite this, a consistent pattern emergent from the data suggesting that (a) EOS patients compared to healthy children and adolescents show impairments of medium to large effect size in IQ, attention, memory and executive function (b) despite increased clinical severity, the cognitive profile of EOS patients is comparable to that of AOS patients (c) healthy adolescents show age-related improvement in their ability to perform tests of attention, memory and executive function; this is not present in EOS patients thus resulting in increased age-related deviance in patients’ performance. This apparent decline is mostly attributable to patients’ failure to acquire new information and to use more sophisticated cognitive strategies.

Is there a degenerative process going on in the brain of people with Schizophrenia?

Schizophrenia is a biological and behavioural disorder which manifests itself in neurocognitive dysfunctions. The question of whether these key characteristics of the disorder are due to schizophrenia being a degenerative disorder has been discussed for more than 100 years. Neuropsychological data indicate that neurocognitive functions are relatively stable over time after illness onset. Several studies show that there is a decline in neurocognitive functioning prior to and in connection with onset of illness. There is no convincing evidence, however, that there is a progressive neurodegenerative process after onset of illness. Morphological data, on the other hand, indicate a degenerative process. Several novel longitudinal studies indicate a rapid reduction of vital brain tissues after onset of illness. In this paper some ideas about compensatory reactions and Cognitive Reserve Theory is outlined as possible explanations of the recent magnetic resonance imaging studies that show structural changes in the brain after the onset of schizophrenia, at the same time as cognitive functioning does not become more impaired. Determining whether schizophrenia is a neurodegenerative illness with progressive structural changes in the brain after debut of the illness, or a neurodevelopmental disorder starting in early life, is of significant importance for understanding the pathophysiology of the illness and its treatments.