Neurocognition in schizophrenia: a 20-year multi-follow-up of the course of processing speed and stored knowledge

New clues for the role of cerebellum in schizophrenia and the associated cognitive impairment

Schizophrenia (SZ) is a complex neuropsychiatric disorder associated with severe cognitive dysfunction. Although research has mainly focused on forebrain abnormalities, emerging results support the involvement of the cerebellum in SZ physiopathology, particularly in Cognitive Impairment Associated with SZ (CIAS). Besides its role in motor learning and control, the cerebellum is implicated in cognition and emotion. Recent research suggests that structural and functional changes in the cerebellum are linked to deficits in various cognitive domains including attention, working memory, and decision-making. Moreover, cerebellar dysfunction is related to altered cerebellar circuit activities and connectivity with brain regions associated with cognitive processing. This review delves into the role of the cerebellum in CIAS. We initially consider the major forebrain alterations in CIAS, addressing impairments in neurotransmitter systems, synaptic plasticity, and connectivity. We then focus on recent findings showing that several mechanisms are also altered in the cerebellum and that cerebellar communication with the forebrain is impaired. This evidence implicates the cerebellum as a key component of circuits underpinning CIAS physiopathology. Further studies addressing cerebellar involvement in SZ and CIAS are warranted and might open new perspectives toward understanding the physiopathology and effective treatment of these disorders.

Neuroimaging features of cognitive impairments in schizophrenia and major depressive disorder

Cognitive dysfunctions are one of the key symptoms of schizophrenia (SZ) and major depressive disorder (MDD), which exist not only during the onset of diseases but also before the onset, even after the remission of psychiatric symptoms. With the development of neuroimaging techniques, these non-invasive approaches provide valuable insights into the underlying pathogenesis of psychiatric disorders and information of cognitive remediation interventions. This review synthesizes existing neuroimaging studies to examine domains of cognitive impairment, particularly processing speed, memory, attention, and executive function in SZ and MDD patients. First, white matter (WM) abnormalities are observed in processing speed deficits in both SZ and MDD, with distinct neuroimaging findings highlighting WM connectivity abnormalities in SZ and WM hyperintensity caused by small vessel disease in MDD. Additionally, the abnormal functions of prefrontal cortex and medial temporal lobe are found in both SZ and MDD patients during various memory tasks, while aberrant amygdala activity potentially contributes to a preference to negative memories in MDD. Furthermore, impaired large-scale networks including frontoparietal network, dorsal attention network, and ventral attention network are related to attention deficits, both in SZ and MDD patients. Finally, abnormal activity and volume of the dorsolateral prefrontal cortex (DLPFC) and abnormal functional connections between the DLPFC and the cerebellum are associated with executive dysfunction in both SZ and MDD. Despite these insights, longitudinal neuroimaging studies are lacking, impeding a comprehensive understanding of cognitive changes and the development of early intervention strategies for SZ and MDD. Addressing this gap is critical for advancing our knowledge and improving patient prognosis.

Cognitive and inflammatory heterogeneity in severe mental illness: Translating findings from blood to brain

Recent findings link cognitive impairment and inflammatory-immune dysregulation in schizophrenia (SZ) and bipolar (BD) spectrum disorders. However, heterogeneity and translation between the periphery and central (blood-to-brain) mechanisms remains a challenge. Starting with a large SZ, BD and healthy control cohort (n = 1235), we aimed to i) identify candidate peripheral markers (n = 25) associated with cognitive domains (n = 9) and elucidate heterogenous immune-cognitive patterns, ii) evaluate the regulation of candidate markers using human induced pluripotent stem cell (iPSC)-derived astrocytes and neural progenitor cells (n = 10), and iii) evaluate candidate marker messenger RNA expression in leukocytes using microarray in available data from a subsample of the main cohort (n = 776), and in available RNA-sequencing deconvolution analysis of postmortem brain samples (n = 474) from the CommonMind Consortium (CMC). We identified transdiagnostic subgroups based on covariance between cognitive domains (measures of speed and verbal learning) and peripheral markers reflecting inflammatory response (CRP, sTNFR1, YKL-40), innate immune activation (MIF) and extracellular matrix remodelling (YKL-40, CatS). Of the candidate markers there was considerable variance in secretion of YKL-40 in iPSC-derived astrocytes and neural progenitor cells in SZ compared to HC. Further, we provide evidence of dysregulated RNA expression of genes encoding YKL-40 and related signalling pathways in a high neuroinflammatory subgroup in the postmortem brain samples. Our findings suggest a relationship between peripheral inflammatory-immune activity and cognitive impairment, and highlight YKL-40 as a potential marker of cognitive functioning in a subgroup of individuals with severe mental illness.

Using latent class analysis to investigate enduring effects of intersectional social disadvantage on long-term vocational and financial outcomes in the 20-year prospective Chicago Longitudinal Study

BACKGROUND

Class and social disadvantage have long been identified as significant factors in the etiology and epidemiology of psychosis. Few studies have explicitly examined the impact of intersecting social disadvantage on long-term employment and financial independence.

METHODS

We applied latent class analysis (LCA) to 20-year longitudinal data from participants with affective and non-affective psychosis (n = 256) within the Chicago Longitudinal Research. LCA groups were modeled using multiple indicators of pre-morbid disadvantage (parental social class, educational attainment, race, gender, and work and social functioning prior to psychosis onset). The comparative longitudinal work and financial functioning of LCA groups were then examined.

RESULTS

We identified three distinct latent classes: one comprised entirely of White participants, with the highest parental class and highest levels of educational attainment; a second predominantly working-class group, with equal numbers of Black and White participants; and a third with the lowest parental social class, lowest levels of education and a mix of Black and White participants. The latter, our highest social disadvantage group experienced significantly poorer employment and financial outcomes at all time-points, controlling for diagnosis, symptoms, and hospitalizations prior to baseline. Contrary to our hypotheses, on most measures, the two less disadvantaged groups did not significantly differ from each other.

CONCLUSIONS

Our analyses add to a growing literature on the impact of multiple forms of social disadvantage on long-term functional trajectories, underscoring the importance of proactive attention to sociostructural disadvantage early in treatment, and the development and evaluation of interventions designed to mitigate ongoing social stratification.

Neuropathological substrate of incident dementia in older patients with schizophrenia: A clinicopathological study

AIM

Clinical studies reported that patients with schizophrenia are at a higher risk of developing dementia than people without schizophrenia. However, early neuropathological studies have shown that the incidence of Alzheimer's disease (AD) in schizophrenia patients does not differ from that in controls. These inconsistent results may be attributable to the inclusion of non-AD dementia, but there have been few clinicopathological studies in older patients with schizophrenia based on the current neuropathological classification. This study aimed to investigate the neuropathological basis of incident dementia in older patients with schizophrenia.

METHODS

We systematically examined 32 brains of old patients with schizophrenia using standardized pathological methods. The severity of dementia-related neuropathologies was analyzed using standardized semiquantitative assessments. After excluding patients who fulfilled the neuropathological criteria, clinicopathological variables were compared between patients with and without incident dementia to identify potential differences.

RESULTS

Seven patients fulfilled the pathological criteria for AD (n = 3), argyrophilic grain disease (AGD) (n = 2), dementia with Lewy bodies (n = 1), and AGD/progressive supranuclear palsy (n = 1). Among 25 patients for whom a neuropathological diagnosis was not obtained, 10 had dementia, but the clinicopathological findings did not differ from the remaining 15 patients without dementia.

CONCLUSION

Two types of older schizophrenia patient present dementia: patients with co-existing neurodegenerative disease and patients who do not meet pathological criteria based on the current classification. To understand the neurobiological aspects of incident dementia in older patients with schizophrenia, further clinicopathological studies are needed that do not simply analyze incident dementia as a comorbidity of conventional dementia-related neuropathologies.

Patterns of Impaired Neurocognitive Performance on the Global Neuropsychological Assessment, and Their Brain Structural Correlates in Recent-onset and Chronic Schizophrenia

Objective

Schizophrenia is associated with impairment in multiple cognitive domains. There is a paucity of research on the effect of prolonged illness duration (≥ 15 years) on cognitive performance along multiple domains. In this pilot study, we used the Global Neuropsychological Assessment (GNA), a brief cognitive battery, to explore the patterns of cognitive impairment in recent-onset (≤ 2 years) compared to chronic schizophrenia (≥ 15 years), and correlate cognitive performance with brain morphometry in patients and healthy adults.

Methods

We assessed cognitive performance in patients with recent-onset (n = 17, illness duration ≤ 2 years) and chronic schizophrenia (n = 14, duration ≥ 15 years), and healthy adults (n = 16) using the GNA and examined correlations between cognitive scores and gray matter volumes computed from T1-weighted magnetic resonance imaging images.

Results

We observed cognitive deficits affecting multiple domains in the schizophrenia samples. Selectively greater impairment of perceptual comparison speed was found in adults with chronic schizophrenia (p = 0.009, η2partial = 0.25). In the full sample (n = 47), perceptual comparison speed correlated significantly with gray matter volumes in the anterior and medial temporal lobes (TFCE, FWE p < 0.01).

Conclusion

Along with generalized deficit across multiple cognitive domains, selectively greater impairment of perceptual comparison speed appears to characterize chronic schizophrenia. This pattern might indicate an accelerated or premature cognitive aging. Anterior-medial temporal gray matter volumes especially of the left hemisphere might underlie the impairment noted in this domain in schizophrenia.

Long-Term Outcome of Clozapine in Treatment-Resistant Schizophrenia

PURPOSE/BACKGROUND

The favorable effect of clozapine on psychotic symptoms in patients with treatment-resistant (TR) schizophrenia (SCZ) in short-term studies is well established. However, prospective studies of the long-term outcome of clozapine treatment on psychopathology, cognition, quality of life, and functional outcome in TR-SCZ are limited.

METHODS/PROCEDURES

Here, we have examined the long-term (mean duration of follow-up 14 years) effects of clozapine on those outcomes in a prospective, open label study in 54 TR-SCZ patients. Assessments were performed at baseline, 6 weeks, 6 months, and at the last follow-up.

FINDINGS/RESULTS

Brief Psychiatric Rating Scale (BPRS) total, positive symptoms, and anxiety/depression at the last follow-up improved significantly from baseline, as well as from the 6-month evaluation ( P < 0.0001), with a 70.5% responder rate (≥20% improvement at the last follow-up from baseline). Quality of Life Scale (QLS) total improved by 72% at the last follow-up, with 24% of patients rated as having "good" functioning compared with 0% at baseline. Suicidal thoughts/behavior was significantly reduced at the last follow-up from the baseline. No significant change in negative symptoms was found at the last follow-up in the total sample. Short-term memory function declined at the last follow-up from baseline, but there was no significant change in processing speed. The QLS total showed a significant negative correlation with BPRS positive symptoms but not with cognitive measures, or negative symptoms, at the last follow-up.

IMPLICATIONS/CONCLUSIONS

For patients with TR-SCZ, improving psychotic symptoms with clozapine seems to have a more significant impact than negative symptoms or cognition on improving psychosocial function.

Cognitive impairment in schizophrenia: aetiology, pathophysiology, and treatment

Cognitive deficits are a core feature of schizophrenia, account for much of the impaired functioning associated with the disorder and are not responsive to existing treatments. In this review, we first describe the clinical presentation and natural history of these deficits. We then consider aetiological factors, highlighting how a range of similar genetic and environmental factors are associated with both cognitive function and schizophrenia. We then review the pathophysiological mechanisms thought to underlie cognitive symptoms, including the role of dopamine, cholinergic signalling and the balance between GABAergic interneurons and glutamatergic pyramidal cells. Finally, we review the clinical management of cognitive impairments and candidate novel treatments.

A five-year follow-up of the verbal memory performance of individuals with bipolar disorder and schizophrenia: evidence of unchanging deficits under treatment

OBJECTIVE

Bipolar disorder (BD) and schizophrenia (SZ) are chronic and heterogeneous mental disorders that present cognitive and functional impairments. Verbal memory is considered an important predictor of functioning and a domain vulnerable to the aging process. However, only few studies investigate the progression of memory longitudinally in BD and SZ, especially in lower- and middle-income countries. Therefore, we aim to evaluate the course of verbal memory in individuals with BD and SZ.

METHODS

We assessed 31 individuals with BD and 27 individuals with SZ under treatment at outpatient clinics at baseline and after five years. They were assessed through a sociodemographic questionnaire, memory and estimated IQ (eIQ) instruments, and clinical scales.

RESULTS

Individuals with SZ showed worse verbal memory performance in comparison to BD, however, we did not observe changes over time within patient groups. Individuals with BD with higher eIQ showed a better verbal memory performance, while no effect of eIQ was found for subjects with SZ.

CONCLUSION

Patients with SZ and BD showed different levels of verbal memory impairment, although they had similar unchanging trajectories after 5 years under psychiatric treatment. This finding indicates a relative stable cognitive course for both disorders.

Education Mediates Racial Disparities in Cognitive Impairment Among Older Adults With Schizophrenia

OBJECTIVES

In the general population, the construct of race is associated with disparities in cognitive aging. There are notable racial group disparities and inequities among people living with schizophrenia (PLWSz). Despite the salience of the construct of race in schizophrenia, there remains a knowledge gap about racial disparities in cognitive impairment among older adults in this vulnerable population. Our study uses mediation analysis to examine racial disparities in cognitive impairment among older adults with schizophrenia.

METHODS

We assess global cognition in PLWSz over age 55 with the Measurement and Treatment Research to Improve Cognition in Schizophrenia cognitive test battery in our "all-comer" sample (N = 64). The primary exposure is self-reported racial group. We examine mediation of cognitive impairment through educational attainment, adjusting for psychiatric illness severity, history of substance use, and vascular risk factors.

RESULTS

There was a Black/non-Black group racial disparity in global cognitive score (-2.8, 95% CI: -4.4, -1.3) after adjusting for confounding and interaction. This disparity was significantly mediated by years of education.

CONCLUSIONS

There are notable racial disparities in cognitive impairment among older adults with schizophrenia; however, differences in cognitive scores between racial groups are mediated by level of education.

CLINICAL IMPLICATIONS

Social determinants of health, particularly educational attainment, are important risk factors for cognitive impairment in PLWSz and should be considered by clinicians. Early screening and assessment of cognitive symptoms is essential to addressing health disparities/inequalities among older adults living with schizophrenia.

ABBREVIATIONS CDE

Controlled Direct EffectsHIV: Human Immunodeficiency VirusMATRICS: Measurement and Treatment Research to Improve Cognition in SchizophreniaMCCB: MATRICS Consensus Cognitive BatteryMTE: Marginal Total EffectsNDE: Natural Direct EffectsPANSS: Positive and Negative Symptom ScalePLWSz: People with schizophrenia.

Neurocognitive correlates of the varied domains of outcomes at 20 year follow-up of first-episode psychosis

Little is known about long-term outcomes of the first episode of psychosis (FEP) other than in the symptomatic domain. We hypothesised that cognitive impairment is associated with poorer multi-domain outcomes at a long-term follow-up of FEP patients. We followed-up 172 FEP patients for a mean of 20.3 years. Ten outcome dimensions were assessed (symptomatic, functional and personal recovery, social disadvantage, physical health, suicide attempts, number of episodes, current drug use, chlorpromazine equivalent doses (CPZ), and schizophrenia/schizoaffective disorder final diagnosis). Cognition was assessed at follow-up. Processing speed and verbal memory deficits showed significant associations with poor outcomes on symptomatic, social functioning, social disadvantage, higher number of episodes, and higher CPZ. Significant associations were found between visual memory impairments were significantly associated with low symptomatic and functional recovery, between attentional deficits and a final diagnosis of schizophrenia/schizoaffective disorder, and between social cognition deficits and poor personal recovery.Lower cognitive global scores were significantly associated with all outcome dimensions except for drug abuse and physical status. Using multiple outcome dimensions allowed for the inclusion of the patients' perspective and other commonly neglected outcome measures. Taken together, cognitive impairment in FEP patients is strongly related to poor performance on several outcome dimensions beyond symptomatic remission.

Domain-specific cognitive course in schizophrenia: Group- and individual-level changes over 10 years

Cognitive impairments in schizophrenia are well-documented, present across several cognitive domains and found to be relatively stable over time. However, there is a high degree of heterogeneity and indications of domain-specific developmental courses. The present study investigated the 10-year cognitive course in participants with first-episode schizophrenia (FES) and healthy controls on eight cognitive domains and a composite score, looking at group- and individual-level changes.

A total of 75 FES participants and 91 healthy controls underwent cognitive assessment at baseline and follow-up. Linear mixed models were used for group-level analyses and reliable change index (RCI) analyses were used to investigate individual change. The prevalence of clinically significant impairment was explored at both time points, using a cut-off of < −1.5 SD, with significant cognitive impairment defined as impairment on ≥2 domains.

Group-level analyses found main effects of group and time, and time by group interactions. Memory, psychomotor processing speed and verbal fluency improved, while learning, mental processing speed and working memory were stable in both groups. FES participants showed deteriorations in attention and cognitive control. Individual-level analyses mainly indicated stability in both FES and controls, except for a higher prevalence of decline in cognitive control in FES. At baseline, 68.8 % of FES participants had clinically significant impairment, compared to 62.3 % at follow-up.

We mainly found long-term stability and modest increases in cognition over time in FES, as well as a high degree of within-group heterogeneity. We also found indications of deterioration in participants with worse cognitive performance at baseline.

The Course of General Cognitive Ability in Individuals With Psychotic Disorders

Importance

Schizophrenia is associated with major cognitive deficits and has been conceptualized as both a neurodevelopmental and a neurodegenerative disorder. However, when deficits develop and how they change over the course of illness is uncertain.

Objective

To trace cognition from elementary school to old age to test neurodevelopmental and neurodegenerative theories of psychotic disorders.

Design, Setting, and Participants

Data were taken from the Suffolk County Mental Health Project, a first-admission longitudinal cohort study of individuals with psychotic disorders. Participants were recruited from all 12 inpatient psychiatric facilities in Suffolk County, New York. This analysis concerns the 428 participants with at least 2 estimates of general cognitive ability. Data were collected between September 1989 and October 2019, and data were analyzed from January 2020 to October 2021.

Exposures

Psychiatric hospitalization for psychosis.

Main Outcomes and Measures

Preadmission cognitive scores were extracted from school and medical records. Postonset cognitive scores were based on neuropsychological testing at 6-month, 24-month, 20-year, and 25-year follow-ups.

Results

Of the 428 included individuals (212 with schizophrenia and 216 with other psychotic disorders), 254 (59.6%) were male, and the mean (SD) age at psychosis onset was 27 (9) years. Three phases of cognitive change were observed: normative, declining, and deteriorating. In the first phase, cognition was stable. Fourteen years before psychosis onset, those with schizophrenia began to experience cognitive decline at a rate of 0.35 intelligence quotient (IQ) points per year (95% CI, 0.29-0.42; P < .001), a significantly faster decline than those with other psychotic disorders (0.15 IQ points per year; 95% CI, 0.08-0.22, P < .001). At 22 years after onset, both groups declined at a rate of 0.59 IQ points per year (95% CI, 0.25-0.94; P < .001).

Conclusions and Relevance

In this cohort study, cognitive trajectories in schizophrenia were consistent with both a neurodevelopmental and neurodegenerative pattern, resulting in a loss of 16 IQ points over the period of observation. Cognitive decline began long prior to psychosis onset, suggesting the window for primary prevention is earlier than previously thought. A window for secondary prevention emerges in the third decade of illness, when cognitive declines accelerate in individuals with schizophrenia and other psychotic disorders.

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.

Neurodegenerative model of schizophrenia: Growing evidence to support a revisit

Multidimensional progressive declines in the absence of standard biomarkers for neurodegeneration are observed commonly in the development of schizophrenia, and are accepted as consistent with neurodevelopmental etiological hypotheses to explain the origins of the disorder. Far less accepted is the possibility that neurodegenerative processes are involved as well, or even that key dimensions of function, such as cognition and aspects of biological integrity, such as white matter function, decline in chronic schizophrenia beyond levels associated with normal aging. We propose that recent research germane to these issues warrants a current look at the question of neurodegeneration. We propose the view that a neurodegenerative hypothesis provides a better explanation of some features of chronic schizophrenia, including accelerated aging, than is provided by neurodevelopmental hypotheses. Moreover, we suggest that neurodevelopmental influences in early life, including those that may extend to later life, do not preclude the development of neurodegenerative processes in later life, including some declines in cognitive and biological integrity. We evaluate these views by integrating recent findings in representative domains such as cognition and white and gray matter integrity with results from studies on accelerated aging, together with functional implications of neurodegeneration for our understanding of chronic schizophrenia.

From the Blood-Brain Barrier to Childhood Development: A Case of Acute-Onset Psychosis and Cognitive Impairment Attributed to Systemic Lupus Erythematosus in an Adolescent Female

LEARNING OBJECTIVES

After participating in this CME activity, the clinician will be better able to:• Interpret classifications of neuropsychiatric systemic lupus erythematosus (NPSLE).• Identify determining factors of neuropsychiatric events.• Analyze current evidence regarding disease pathways for NPSLE.

White Matter Alterations Between Brain Network Hubs Underlie Processing Speed Impairment in Patients With Schizophrenia

Processing speed (PS) impairment is one of the most severe and common cognitive deficits in schizophrenia. Previous studies have reported correlations between PS and white matter diffusion properties, including fractional anisotropy (FA), in several fiber bundles in schizophrenia, suggesting that white matter alterations could underpin decreased PS. In schizophrenia, white matter alterations are most prevalent within inter-hub connections of the rich club. However, the spatial and topological characteristics of this association between PS and FA have not been investigated in patients. In this context, we tested whether structural connections comprising the rich club network would underlie PS impairment in 298 patients with schizophrenia or schizoaffective disorder and 190 healthy controls from the Australian Schizophrenia Research Bank. PS, measured using the digit symbol coding task, was largely (Cohen’s d = 1.33) and significantly (P < .001) reduced in the patient group when compared with healthy controls. Significant associations between PS and FA were widespread in the patient group, involving all cerebral lobes. FA was not associated with other cognitive measures of phonological fluency and verbal working memory in patients, suggesting specificity to PS. A topological analysis revealed that despite being spatially widespread, associations between PS and FA were over-represented among connections forming the rich club network. These findings highlight the need to consider brain network topology when investigating high-order cognitive functions that may be spatially distributed among several brain regions. They also reinforce the evidence that brain hubs and their interconnections may be particularly vulnerable parts of the brain in schizophrenia.

Association Between the Duration of Untreated Psychosis and Selective Cognitive Performance in Community-Dwelling Individuals With Chronic Untreated Schizophrenia in Rural China

IMPORTANCE

Cognitive deficits constitute core features of schizophrenia, but the trajectories of cognitive difficulties in chronic untreated schizophrenia remain unclear.

OBJECTIVE

To assess the association of neuropsychological deficits with duration of untreated psychosis in individuals with chronic untreated schizophrenia.

DESIGN, SETTING, AND PARTICIPANTS

Community-dwelling individuals with chronic untreated schizophrenia (untreated patient group) and individuals without mental illness (control group) were recruited from predominantly rural communities in Ningxia, China between June 20, 2016, and August 6, 2019, and administered the Structured Clinical Interview for DSM-IV, the Mini-Mental State Examination, an 8-test version of the MATRICS Consensus Cognition Battery adapted for use in individuals with low levels of education, and a measure of social cognition.

MAIN OUTCOMES AND MEASURES

Comparison of cognitive test scores between the two groups and association of cognitive test scores with duration of untreated schizophrenia.

RESULTS

The patient group included 197 individuals with chronic untreated schizophrenia (101 men [51.3%]; mean [SD] age, 52.1 [11.8] years; median [interquartile range] years of schooling, 3 [0-6] years; median [interquartile range] years of untreated psychosis, 22.9 [14.9-32.8] years). The control group included 220 individuals (118 men [53.6%]; mean [SD] age, 52.1 [11.2] years; median [interquartile range] years of schooling, 4 [0-6] years). The untreated patient group performed significantly worse than the control group on all cognitive measures (adjusted partial Spearman correlation coefficient [Spearman ρ] ranged from -0.35 for the revised Chinese version of the Reading the Mind in the Eyes Test to -0.60 for the Brief Visuospatial Memory Test-Revised; P < .001 for all comparisons). Longer durations of untreated psychosis were associated with lower performance in 3 MATRICS Consensus Cognition Battery measures assessing different aspects of executive functioning (Brief Visuospatial Memory Test-Revised [ρ = -0.20; P = .04]; Brief Assessment of Cognition in Schizophrenia, Symbol Coding subtest [ρ = -0.35; P < .001]; and Neuropsychological Assessment Battery, Mazes subtest [ρ = -0.24; P = .01]). The median duration of untreated psychosis (22.9 years) was associated with estimated score reductions in the 3 measures of 34% (95% CI, 10%-52%), 43% (95% CI, 28%-55%), and 57% (95% CI, 31%-73%), respectively.

CONCLUSIONS AND RELEVANCE

The findings of this study suggest that long-term untreated schizophrenia was associated with decreases in selective cognitive abilities; both neurodegenerative pathology and neurodevelopmental dysfunction may be factors in cognition in persistent psychosis. Expanding research to include cohorts of patients from underserved rural communities in low- and middle-income countries may provide new insights about the etiological factors, disease course, and management of schizophrenia.

Psychomotor Slowing in Schizophrenia: Implications for Endophenotype and Biomarker Development

Motor abnormalities (e.g., dyskinesia, psychomotor slowing, neurological soft signs) are core features of schizophrenia that occur independent of drug treatment and are associated with the genetic vulnerability and pathophysiology for the illness. Among this list, psychomotor slowing in particular is one of the most consistently observed and robust findings in the field. Critically, psychomotor slowing may serve as a uniquely promising endophenotype and/or biomarker for schizophrenia considering it is frequently observed in those with genetic vulnerability for the illness, predicts transition in subjects at high-risk for the disorder, and is associated with symptoms and recovery in patients. The purpose of the present review is to provide an overview of the history of psychomotor slowing in psychosis, discuss its possible neural underpinnings, and review the current literature supporting slowing as a putative endophenotype and/or biomarker for the illness. This review summarizes substantial evidence from a diverse array of methodologies and research designs that supports the notion that psychomotor slowing not only reflects genetic vulnerability, but is also sensitive to disease processes and the pathophysiology of the illness. Furthermore, there are unique deficits across the cognitive (prefix "psycho") and motor execution (root word "motor") aspects of slowing, with cognitive processes such as planning and response selection being particularly affected. These findings suggest that psychomotor slowing may serve as a promising endophenotype and biomarker for schizophrenia that may prove useful for identifying individuals at greatest risk and tracking the course of the illness and recovery.

The effects of age and sex on cognitive impairment in schizophrenia: Findings from the Consortium on the Genetics of Schizophrenia (COGS) study

Recently emerging evidence indicates accelerated age-related changes in the structure and function of the brain in schizophrenia, raising a question about its potential consequences on cognitive function. Using a large sample of schizophrenia patients and controls and a battery of tasks across multiple cognitive domains, we examined whether patients show accelerated age-related decline in cognition and whether an age-related effect differ between females and males. We utilized data of 1,415 schizophrenia patients and 1,062 healthy community collected by the second phase of the Consortium on the Genetics of Schizophrenia (COGS-2). A battery of cognitive tasks included the Letter-Number Span Task, two forms of the Continuous Performance Test, the California Verbal Learning Test, Second Edition, the Penn Emotion Identification Test and the Penn Facial Memory Test. The effect of age and gender on cognitive performance was examined with a general linear model. We observed age-related changes on most cognitive measures, which was similar between males and females. Compared to controls, patients showed greater deterioration in performance on attention/vigilance and greater slowness of processing social information with increasing age. However, controls showed greater age-related changes in working memory and verbal memory compared to patients. Age-related changes (η2p of 0.001 to .008) were much smaller than between-group differences (η2p of 0.005 to .037). This study found that patients showed continued decline of cognition on some domains but stable impairment or even less decline on other domains with increasing age. These findings indicate that age-related changes in cognition in schizophrenia are subtle and not uniform across multiple cognitive domains.

Effect of DISC1 Polymorphisms on the Long-term Course of Neurocognitive Deficits in Non-affective Psychosis

Neurocognitive deficits are core symptoms of schizophrenia that determine a poorer outcome. High variability in the progression of neuropsychological deficits in schizophrenia has been described. It is still unknown whether genetic variations can affect the course of cognitive deficits. Variations in the Disrupted in Schizophrenia 1 (DISC1) gene have previously been associated with neurocognitive deficits. This study investigated the association between 3 DISC1 polymorphisms (rs6675281 (Leu607Phe), rs1000731, and rs821616 (Ser704Cys)) and long-term (3 years) cognitive performance. One-hundred-thirty-three Caucasian drug-naive patients experiencing a first episode of non-affective psychosis were genotyped. Cognitive function was assessed at baseline and after 3 years of initiating treatment. Other clinical and socio-demographic variables were recorded to eliminate potential confounding effects. Patients carrying the A allele of rs1000731 exhibited a significant improvement in Working Memory and Attention domains, and the homozygosity of the A allele of rs821616 showed a significant improvement in Motor Dexterity performance over 3 years of follow-up. In conclusion, DISC1 gene variations may affect the course of cognitive deficits found in patients suffering from the first episode of non-affective psychosis.

Long-term Changes in Cognitive Functioning in Individuals With Psychotic Disorders: Findings From the Suffolk County Mental Health Project

IMPORTANCE

It remains uncertain whether people with psychotic disorders experience progressive cognitive decline or normal cognitive aging after first hospitalization. This information is essential for prognostication in clinical settings, deployment of cognitive remediation, and public health policy.

OBJECTIVE

To examine long-term cognitive changes in individuals with psychotic disorders and to compare age-related differences in cognitive performance between people with psychotic disorders and matched control individuals (ie, individuals who had never had psychotic disorders).

DESIGN, SETTING, AND PARTICIPANTS

The Suffolk County Mental Health Project is an inception cohort study of first-admission patients with psychosis. Cognitive functioning was assessed 2 and 20 years later. Patients were recruited from the 12 inpatient facilities of Suffolk County, New York. At year 20, the control group was recruited by random digit dialing and matched to the clinical cohort on zip code and demographics. Data were collected between September 1991 and July 2015. Analysis began January 2016.

MAIN OUTCOMES AND MEASURES

Change in cognitive functioning in 6 domains: verbal knowledge (Wechsler Adult Intelligence Scale-Revised vocabulary test), verbal declarative memory (Verbal Paired Associates test I and II), visual declarative memory (Visual Reproduction test I and II), attention and processing speed (Symbol Digit Modalities Test-written and oral; Trail Making Test [TMT]-A), abstraction-executive function (Trenerry Stroop Color Word Test; TMT-B), and verbal fluency (Controlled Oral Word Association Test).

RESULTS

A total of 705 participants were included in the analyses (mean [SD] age at year 20, 49.4 [10.1] years): 445 individuals (63.1%) had psychotic disorders (211 with schizophrenia spectrum [138 (65%) male]; 164 with affective psychoses [76 (46%) male]; 70 with other psychoses [43 (61%) male]); and 260 individuals (36.9%) in the control group (50.5 [9.0] years; 134 [51.5%] male). Cognition in individuals with a psychotic disorder declined on all but 2 tests (average decline: d = 0.31; range, 0.17-0.54; all P < .001). Cognitive declines were associated with worsening vocational functioning (Visual Reproduction test II: r = 0.20; Symbol Digit Modalities Test-written: r = 0.25; Stroop: r = 0.24; P < .009) and worsening negative symptoms (avolition: Symbol Digit Modalities Test-written: r = -0.24; TMT-A: r = -0.21; Stroop: r = -0.21; all P < .009; inexpressivity: Stroop: r = -0.22; P < .009). Compared with control individuals, people with psychotic disrders showed age-dependent deficits in verbal knowledge, fluency, and abstraction-executive function (vocabulary: β = -0.32; Controlled Oral Word Association Test: β = -0.32; TMT-B: β = 0.23; all P < .05), with the largest gap among participants 50 years or older.

CONCLUSIONS AND RELEVANCE

In individuals with psychotic disorders, most cognitive functions declined over 2 decades after first hospitalization. Observed declines were clinically significant. Some declines were larger than expected due to normal aging, suggesting that cognitive aging in some domains may be accelerated in this population. If confirmed, these findings would highlight cognition as an important target for research and treatment during later phases of psychotic illness.

[Cognitive disorders in schizophrenia]

Cognitive disorders in schizophrenia are highly correlated with the psychosocial level (e.g. relationships, quality of life and work). It has been shown that healthy relatives and people at ultrahigh risk also display cognitive dysfunctions albeit to a lesser degree. The cognitive impairment increases simultaneously with an acute phase and then reverts back to baseline levels. At the psychopathological level, negative symptoms and the disorganization syndrome show the strongest associations with cognitive deficits, whereby the extent of manifestation of deficits increases with increasing symptomatology. Cognitive remediation can improve the cognitive performance through training with small to moderate effects. With respect to drug therapy there is currently no drug with a positive effect on cognitive disorders.

Cognitive impairment from early to middle adulthood in patients with affective and nonaffective psychotic disorders

BACKGROUND

Cognitive impairment is a core feature of psychotic disorders, but the profile of impairment across adulthood, particularly in African-American populations, remains unclear.

METHODS

Using cross-sectional data from a case-control study of African-American adults with affective (n = 59) and nonaffective (n = 68) psychotic disorders, we examined cognitive functioning between early and middle adulthood (ages 20-60) on measures of general cognitive ability, language, abstract reasoning, processing speed, executive function, verbal memory, and working memory.

RESULTS

Both affective and nonaffective psychosis patients showed substantial and widespread cognitive impairments. However, comparison of cognitive functioning between controls and psychosis groups throughout early (ages 20-40) and middle (ages 40-60) adulthood also revealed age-associated group differences. During early adulthood, the nonaffective psychosis group showed increasing impairments with age on measures of general cognitive ability and executive function, while the affective psychosis group showed increasing impairment on a measure of language ability. Impairments on other cognitive measures remained mostly stable, although decreasing impairments on measures of processing speed, memory and working memory were also observed.

CONCLUSIONS

These findings suggest similarities, but also differences in the profile of cognitive dysfunction in adults with affective and nonaffective psychotic disorders. Both affective and nonaffective patients showed substantial and relatively stable impairments across adulthood. The nonaffective group also showed increasing impairments with age in general and executive functions, and the affective group showed an increasing impairment in verbal functions, possibly suggesting different underlying etiopathogenic mechanisms.

Social vs. non-social measures of learning potential for predicting community functioning across phase of illness in schizophrenia

Studies demonstrate that dynamic assessment (i.e., learning potential) improves the prediction of response to rehabilitation over static measures in individuals with schizophrenia. Learning potential is most commonly assessed using neuropsychological tests under a test-train-test paradigm to examine change in performance. Novel learning potential approaches using social cognitive tasks may have added value, particularly for the prediction of social functioning, but this area is unexplored. The present study is the first to investigate whether patients with schizophrenia demonstrate social cognitive learning potential across phase of illness. This study included 43 participants at clinical high risk (CHR), 63 first-episode, and 36 chronic schizophrenia patients. Assessment of learning potential involved test-train-test versions of the Wisconsin Card Sorting Test (non-social cognitive learning potential) and the Facial Emotion Identification Test (social cognitive learning potential). Non-social and social cognition pre-training scores (static scores) uniquely predicted concurrent community functioning in patients with schizophrenia, but not in CHR participants. Learning potential showed no incremental explanation of variance beyond static scores. First-episode patients showed larger non-social cognitive learning potential than CHR participants and were similar to chronic patients; chronic patients and CHR participants were similar. Group differences across phase of illness were not observed for social cognitive learning potential. Subsequent research could explore whether non-social and social cognitive learning potential relate differentially to non-social versus social types of training and rehabilitation.

Cognitive improvement in first-episode schizophrenia and healthy controls: A 6-year multi-assessment follow-up study

The development of individual cognitive domains over time is not yet fully examined in first-episode schizophrenia (FES). This study's objective was to explore the cognitive trajectories of FES-patients (n = 28) and compare them to a pairwise matched healthy control group (n = 28, total n = 56). This study has a multi-assessment design, and includes patient data from seven assessments over six years. Healthy controls were assessed at baseline, after two years and after six years. Cognition was assessed with the MATRICS Consensus Cognitive Battery. Data were analyzed with linear multilevel models. FES-patients scored significantly lower than the control group across all cognitive domains at baseline. Over six years, improvements were seen in attention, verbal learning, processing speed, reasoning/ problem solving, working memory and social cognition. The overall trend points toward a similar cognitive change in both groups. The patient group's improvement in reasoning/ problem solving was significantly larger that the control group, but improvement in working memory was smaller. Cognitive improvements were seen under and after the initial psychosis episode and throughout the recovery process with 45.5% of the patients fully recovered by 6-year follow-up. Cognitive improvements were seen in almost every cognitive domain that is consistently impaired in FES.

A neurodevelopment and neuroplasticity-based framework for early intervention in psychotic disorders

In recent years there has been growing interest in early intervention in psychotic disorders and a number of clinical and research programmes have been developed. The clinical staging model has been an essential part of early intervention as it provides the rationale of existing programmes. In medicine, clinical staging is a valuable approach in disorders where primary pathology is progressive in nature. However, the clinical staging model of psychosis has been proposed without establishing first that schizophrenia is a primarily progressive disorder. In reviewing existing evidence, this current paper argues that cross-sectional data interpreted as supportive of clinical staging data does not consider the effects of sampling bias, problems in reliability in assessing 'soft symptoms', or false positives. Longitudinal neurobiological studies do not provide a convincing case for primarily progressive pathology in schizophrenia. Clinical progression in schizophrenia can be better conceptualised as neuroplastic changes in response to interaction between core developmental pathology and environmental stimuli. An alternative rationale for early and continuous intervention targeting neurodevelopmental abnormality and neuroplastic changes, as well as medical and psychological comorbidities, is proposed in this paper.

The relationship between level of cognitive impairments and functional outcome trajectories in first-episode schizophrenia

Although cognitive impairments are consistently linked to functional outcome in chronic schizophrenia, the relationship remains unclear for patients with first-episode schizophrenia. The objective of this present study was to determine whether there are distinct developmental trajectories for functional outcome in patients with different levels of baseline cognition. The present study has a multi-follow-up design, and includes data from six follow-ups over four years. Assessments were conducted yearly, apart from the first year where assessments were conducted every six months. A total of 28 patients with first-episode schizophrenia participated in the study, with 79% of patients retained at the 4-year follow-up. Cognition was assessed with MATRICS Consensus Cognitive Battery. Functional outcomes were obtained through Global functioning: Social and Global functioning: Role. Data were analyzed with linear multilevel models. Results suggest steady improvements in social and role functioning among the patients across the four year period. Baseline attention, verbal learning, and verbal working memory were significantly associated with social outcome. Role functioning was significantly associated with attention, verbal working memory, and reasoning/problem solving. Furthermore, the rate of change in social outcome varies among patients depending on their baseline level of attention and verbal working memory, with the lowest scoring group showing the least improvement over the years. The subgroup of patients with the largest cognitive impairments at the onset of the disorder shows limited improvements in social functioning compared to higher functioning groups.

Meta-analysis of longitudinal studies of cognition in bipolar disorder: comparison with healthy controls and schizophrenia

BACKGROUND

Bipolar disorder (BP) is associated with significant cognitive impairment. Recent evidence suggests that cognitive deficits are already evident after first-episode mania. However, it is not clear whether BP is associated with further decline in cognitive functions in individuals with established illness. Aim of this meta-analytic review was to examine longitudinal neurocognitive changes in BP and to compare trajectory of cognitive deficits in BP with schizophrenia and healthy controls.

METHODS

Electronic databases were searched for the studies published between January 1987 and November 2016. In total 22 reports were included in the current meta-analysis. The main analysis assessed the longitudinal change in cognition in 643 patients with BP. Further analyses were conducted in studies investigating cognitive changes in BP along with healthy controls (459 BP and 367 healthy controls) and schizophrenia (172 BP and 168 schizophrenia).

RESULTS

There was no cognitive decline overtime neither in short-term (mean duration = 1.5 years) nor in long-term (mean duration = 5.5 years) follow-up studies in BP. In contrast, there was evidence for modest improvements in task performance in memory and working memory at follow-up. The trajectory of cognitive functioning in BP was not significantly different from changes in schizophrenia and healthy controls.

CONCLUSIONS

Together with the findings in early BP and individuals at genetic risk for BP, current findings suggest that neurodevelopmental factors might play a significant role in cognitive deficits in BP and do not support the notion of progressive cognitive decline in most patients with BP.

The impact of chronic psychiatric disorders on cognitive decline

OBJECTIVES

Based on seemingly contradictory results in the existing literature, the objective of our study was to investigate whether older individuals suffering from chronic psychiatric disorders show a more rapid decline in cognitive performances than their non-psychiatric counterparts, or if the pattern of decline through older age is similar in both groups.

METHOD

A total of 820 older adults were selected from the Ageing Multidisciplinary Investigation (AMI) cohort study, which studies health-related issues of people over 65 years old living in rural areas. Among them, 30 suffer from chronic psychiatric disorders. Cognition was assessed with four neuropsychological tests: the Mini-Mental State Examination, the Digit Symbol Substitution Test, the Free and Cued Selective Reminding test and the Isaacs Set Test. Linear mixed models were used to compare the evolution of cognitive performances in the two groups between baseline and the four-year follow-up.

RESULTS

Despite lower performances at baseline, the pattern of cognitive decline of the psychiatric group is similar to that of the control group.

CONCLUSION

As suggested by this study conducted in rural communities, community-dwelling people suffering from chronic psychiatric disorders should not be considered at greater risk of age-related accelerated cognitive decline than the non-psychiatric older population.

Working memory predicts presence of auditory verbal hallucinations in schizophrenia and bipolar disorder with psychosis

OBJECTIVE

The recent dramatic increase in research investigating auditory verbal hallucinations (AVHs) has broadened the former narrow focus on schizophrenia to incorporate additional populations that experience these symptoms. However, an understanding of potential shared mechanisms remains elusive. Based on theories suggesting a failure of top-down cognitive control, we aimed to compare the relationship between AVHs and cognition in two categorical diagnoses of psychosis, schizophrenia and psychotic bipolar disorder.

METHOD

A total of 124 adults aged 21-60 participated, of whom 76 had present-state psychosis (schizophrenia, n = 53; bipolar disorder with psychosis, n = 23), and 48 were non-clinical controls. Diagnosis and hallucination presence was determined using the Structured Clinical Diagnostic Interview for DSM-IV TR. AVHs severity was assessed using the Positive and Negative Syndrome Scale. Participants also completed the MATRICS cognitive battery.

RESULTS

The bipolar disorder with psychosis group performed better than the schizophrenia group for cognitive domains of Processing speed, Attention, Working memory (WM), and Visual memory. Hierarchical binary logistic regression found that WM significantly predicted presence of AVHs in both psychotic groups, but diagnosis did not significantly increase the predictive value of the model. A hierarchical multiple linear regression found that schizophrenia diagnosis was the only significant predictor of hallucination severity.

CONCLUSIONS

The findings of this study-the first, to our knowledge, to compare the relationship between AVHs and MATRICS domains across schizophrenia and bipolar disorder with psychosis-support theories that deficits in WM underly the genesis of AVHs. WM potentially represents a shared mechanism of AVHs across diagnoses, supporting dimensional classifications of these psychotic disorders. However, non-cognitive factors predictive of hallucination severity may be specific to schizophrenia.

From neurocognition to community participation in serious mental illness: the intermediary role of dysfunctional attitudes and motivation

BACKGROUND

Evidence for a relationship between neurocognition and functional outcome in important areas of community living is robust in serious mental illness research. Dysfunctional attitudes (defeatist performance beliefs and asocial beliefs) have been identified as intervening variables in this causal chain. This study seeks to expand upon previous research by longitudinally testing the link between neurocognition and community participation (i.e. time in community-based activity) through dysfunctional attitudes and motivation.

METHOD

Adult outpatients with serious mental illness (N = 175) participated, completing follow-up assessments approximately 6 months after initial assessment. Path analysis tested relationships between baseline neurocognition, emotion perception, functional skills, dysfunctional attitudes, motivation, and outcome (i.e. community participation) at baseline and follow-up.

RESULTS

Path models demonstrated two pathways to community participation. The first linked neurocognition and community participation through functional skills, defeatist performance beliefs, and motivation. A second pathway linked asocial beliefs and community participation, via a direct path passing through motivation. Model fit was excellent for models predicting overall community participation at baseline and, importantly, at follow-up.

CONCLUSIONS

The existence of multiple pathways to community participation in a longitudinal model supports the utility of multi-modal interventions for serious mental illness (i.e. treatment packages that build upon individuals' strengths while addressing the array of obstacles to recovery) that feature dysfunctional attitudes and motivation as treatment targets.

Cognitive Functioning in Older Adults With Schizophrenia

Cognitive deficits are thought to be a core feature in schizophrenia and have been found to be strongly associated with impairments in functioning. It is estimated that more than 70% of patients with schizophrenia have cognitive impairment. The aim of this article is to critically review the emerging literature on cognition in older adults with schizophrenia. Specifically, we address the following questions: Are there differences in cognitive functioning between older adults with schizophrenia and their healthy age peers as well as with younger people with schizophrenia? What are the factors associated with cognitive deficits and their interaction over time? What are the life course trajectories of cognitive deficits, especially in later life? Are older adults with schizophrenia more likely to develop dementia, and, if so, does it differ from other dementias? Are there pharmacological and psychosocial interventions that can successfully treat cognitive deficits in older adults with schizophrenia?

Diffusion-weighted imaging uncovers likely sources of processing-speed deficits in schizophrenia

Schizophrenia, a devastating psychiatric illness with onset in the late teens to early 20s, is thought to involve disrupted brain connectivity. Functional and structural disconnections of cortical networks may underlie various cognitive deficits, including a substantial reduction in the speed of information processing in schizophrenia patients compared with controls. Myelinated white matter supports the speed of electrical signal transmission in the brain. To examine possible neuroanatomical sources of cognitive deficits, we used a comprehensive diffusion-weighted imaging (DWI) protocol and characterized the white matter diffusion signals using diffusion kurtosis imaging (DKI) and permeability-diffusivity imaging (PDI) in patients (n = 74), their nonill siblings (n = 41), and healthy controls (n = 113). Diffusion parameters that showed significant patient-control differences also explained the patient-control differences in processing speed. This association was also found for the nonill siblings of the patients. The association was specific to processing-speed abnormality but not specific to working memory abnormality or psychiatric symptoms. Our findings show that advanced diffusion MRI in white matter may capture microstructural connectivity patterns and mechanisms that govern the association between a core neurocognitive measure-processing speed-and neurobiological deficits in schizophrenia that are detectable with in vivo brain scans. These non-Gaussian diffusion white matter metrics are promising surrogate imaging markers for modeling cognitive deficits and perhaps, guiding treatment development in schizophrenia.

Twenty year multi-follow-up of different types of hallucinations in schizophrenia, schizoaffective disorder, bipolar disorder, and depression

Hallucinations are a salient feature of both psychotic and mood disorders. Currently there is a call for more research on the phenomenology of different forms of hallucinations, in a broader array of disorders, to further both theoretical knowledge and clinical utility. We investigated auditory, visual, and olfactory hallucinations at index hospitalization and auditory and visual hallucinations prospectively for 20years in 150 young patients, namely 51 schizophrenia, 25 schizoaffective, 28 bipolar, and 79 unipolar depression. For the index hospitalization, the data showed schizophrenia and schizoaffective patients had a greater rate of auditory and visual hallucinations than bipolar and depression patients. However, over the longitudinal trajectory of their illness, a greater percentage of schizophrenia patients had auditory and visual hallucinations than schizoaffective patients, as well as bipolar and depression patients. Also, in contrast to the initial period, schizoaffective patients did not differentiate themselves over the follow-up period from bipolar patients. Bipolar and depression patients did not significantly differ at index hospitalization or at follow-up. We found visual hallucinations differentiated the groups to a greater degree over the 20year course than did auditory hallucinations. These findings suggest the longitudinal course is more important for differentiating schizophrenia and schizoaffective disorder, whereas the initial years may be more useful to differentiate schizoaffective disorder from bipolar disorder. Furthermore, we found that the early presence of auditory hallucinations was associated with a reduced likelihood for a future period of recovery. No olfactory hallucinations were present at the index hospitalization in any patients. Over the course of 20years, a minority of schizophrenia patients presented with olfactory hallucinations, and very few schizoaffective and bipolar patients presented with olfactory hallucinations. This study underscores the importance of the longitudinal course of symptoms to understand the relationship between related disorders and recovery.

Longitudinal stability of social cognition in schizophrenia: A 5-year follow-up of social perception and emotion processing

BACKGROUND

Individuals with schizophrenia exhibit marked and disproportional impairment in social cognition, which is associated with their level of community functioning. However, it is unclear whether social cognitive impairment is stable over time, or if impairment worsens as a function of illness chronicity. Moreover, little is known about the longitudinal associations between social cognition and community functioning.

METHOD

Forty-one outpatients with schizophrenia completed tests of emotion processing (Mayer-Salovey-Caruso Emotional Intelligence Test, MSCEIT) and social perception (Relationships Across Domains, RAD) at baseline and approximately five years later. Stability of performance was assessed using paired t-tests and correlations. Longitudinal associations between social cognition and community functioning (Role Functioning Scale, RFS) were assessed using cross-lagged panel correlation analysis.

RESULTS

Performance on the two social cognition tasks were stable over follow-up. There were no significant mean differences between assessment points [p's≥0.20, Cohen'sd's≤|0.20|], and baseline performance was highly correlated with performance at follow-up [ρ's≥0.70, ICC≥0.83, p's<0.001]. The contemporaneous association between social cognition and community functioning was moderately large at follow-up [ρ=0.49, p=0.002]. However, baseline social cognition did not show a significant longitudinal influence on follow-up community functioning [z=0.31, p=0.76].

CONCLUSIONS

These data support trait-like stability of selected areas of social cognition in schizophrenia. Cross-lagged correlations did not reveal a significant unidirectional influence of baseline social cognition on community functioning five years later. However, consistent with the larger literature, a moderately large cross-sectional association between social cognition and community functioning was observed. Based on stability and cross-sectional associations, these results suggest that social cognition might have short-term implications for functional outcome rather than long-term consequences.

The Longitudinal Course of Schizophrenia Across the Lifespan: Clinical, Cognitive, and Neurobiological Aspects

Despite several decades of research, our knowledge of the long-term course of schizophrenia (SZ) is hampered by a lack of homogeneity of both research methods and phenotypic definitions of SZ's course. We provide a comprehensive review of the course of SZ by applying stringent methodological and diagnostic study-selection criteria. We report on positive and negative symptoms, cognition, and findings obtained by neuroimaging. In addition, we perform a meta-analysis of longitudinal studies of cognition in humans. We selected 35 human studies focusing on a narrow SZ phenotype, employing a follow-up duration of six months or more and consistent methodology at the different measurement points. For the meta-analysis on global cognitive change, eight and four studies were used to compare SZ to healthy and psychiatric controls, respectively. We find that the course of SZ is characterized by a constancy or even improvement of positive and negative symptoms and by fairly stable cognitive impairment, reflecting structural frontal and temporal cortical pathology. Progressive changes of the frontal cortex appear to develop in parallel with changes in symptomatology and executive impairment. Despite stable differences in cognition between patients and controls over the time intervals studied, high heterogeneity in the magnitude of effect sizes is present, and age is identified as one of its potential sources. Meta-regression shows these magnitudes to depend on the age at study inclusion. For future research, a combination of longitudinal and cross-sectional research designs is warranted to better account for potential cohort effects.

Long-term trajectories of cognitive deficits in schizophrenia: A critical overview

BACKGROUND

Cognitive disturbances are widely pronounced in schizophrenia and schizophrenia spectrum disorders. Whilst cognitive deficits are well established in the prodromal phase and are known to deteriorate at the onset of schizophrenia, there is a certain discrepancy of findings regarding the cognitive alterations over the course of the illness.

METHODS

We bring together the results of the longitudinal studies identified through PubMed which have covered more than 3 years follow-up and to reflect on the potential factors, such as sample characteristics and stage of the illness which may contribute to the various trajectories of cognitive changes.

RESULTS

A summary of recent findings comprising the changes of the cognitive functioning in schizophrenia patients along the longitudinal course of the illness is provided. The potential approaches for addressing cognition in the course of schizophrenia are discussed.

CONCLUSIONS

Given the existing controversies on the course of cognitive changes in schizophrenia, differentiated approaches specifically focusing on the peculiarities of the clinical features and changes in specific cognitive domains could shed light on the trajectories of cognitive deficits in schizophrenia and spectrum disorders.

Perfusion shift from white to gray matter may account for processing speed deficits in schizophrenia

Reduced speed of cerebral information processing is a cognitive deficit associated with schizophrenia. Normal information processing speed (PS) requires intact white matter (WM) physiology to support information transfer. In a cohort of 107 subjects (47/60 patients/controls), we demonstrate that PS deficits in schizophrenia patients are explained by reduced WM integrity, which is measured using diffusion tensor imaging, mediated by the mismatch in WM/gray matter blood perfusion, and measured using arterial spin labeling. Our findings are specific to PS, and testing this hypothesis for patient-control differences in working memory produces no explanation. We demonstrate that PS deficits in schizophrenia can be explained by neurophysiological alterations in cerebral WM. Whether the disproportionately low WM integrity in schizophrenia is due to illness or secondary due to this disorder deserves further examination.

From hospital admission to independent living: is prediction possible?

An integral component of recovery from mental illness is being able to engage in everyday activities. This ability is often restricted among people with schizophrenia. Although functional deficits are addressed during hospitalization, the ability to predict daily functioning based on information gathered during hospitalization has not been well established. This study examines whether measurements completed during hospitalization can be useful for predicting independent living within the community. Inpatients with schizophrenia (N=104) were enrolled in the study and assessed for cognitive functioning, functional capacity and symptoms. They were approached again 6 months after discharge to evaluate their functioning with respect to everyday life Instrumental Activities of Daily Living (IADL) and Activities of Daily Living (ADL). Functional capacity during hospitalization predicted 26.8% of ADL functioning and 38.8% of IADL functioning. ADL was best predicted by the severity of negative symptoms, cognitive functioning, and the number of hospitalizations (51.2%), while IADL was best predicted by functional capacity, cognition, and number of hospitalizations (60.1%). This study provides evidence that evaluations during hospitalization can be effective, and demonstrates the advantage of a holistic approach in predicting daily functioning. When a holistic approach is not practical, a functional capacity measurement may serve as an effective predictor.

The effects of aging on insight into illness in schizophrenia: a review

OBJECTIVES

Impaired insight into illness is a prevalent feature of schizophrenia, which negatively influences treatment adherence and clinical outcomes. Little is known about the effects of aging on insight impairment. We aimed to review the available research literature on the effects of aging on insight into illness in schizophrenia, in relation to positive, negative, and cognitive symptoms. Ultimately, we propose a trajectory of insight in schizophrenia across the lifespan.

METHOD

A systematic Medline® literature search was conducted, searching for English language studies describing the relationship of insight into illness in schizophrenia with aging.

RESULTS

We identified 62 studies. Insight impairment is associated with illness severity, premorbid intellectual function (i.e. IQ), executive function, and memory. Insight impairment improves modestly during midlife, worsening again in late life. It tends to fluctuate with each episode of psychosis, likely in relation to worsening positive symptoms that improve with antipsychotic treatment. The relationship between insight impairment and cognitive dysfunction appears to attenuate with age, while the relationship with lower premorbid intellectual function is preserved. The association between impaired insight and negative symptoms is unclear.

CONCLUSIONS

The available literature suggests that the course of insight impairment follows a U-shaped curve, where insight impairment is severe during the first episode of psychosis, modestly improves over midlife, and declines again in late life. Future studies are required to investigate the trajectory of insight into illness and its core domains across the lifespan from prodromal phase to late life.

Testing trait depression as a potential clinical domain in schizophrenia

The DSM-5 includes depression as a dimension of psychosis. We tested whether persistent experience of depression, called 'trait depression', is a clinical feature separate from psychosis and several well-known, trait-like deficits of schizophrenia. 126 individuals with schizophrenia and 151 control participants completed the Maryland Trait and State Depression questionnaire, with a subset completing measures of cognition and functional capacity, and diffusion tensor imaging (n=73 patients and 102 controls for imaging analysis). Subjectively experienced, longitudinal trait depression is significantly higher in patients with schizophrenia compared with controls. Higher trait depression scores were associated with more severe psychosis. Surprisingly, individuals with higher trait depression manifested less cognitive and global functioning deficits. In addition, trait depression scores were positively associated with fractional anisotropy of white matter. Trait depression appears to be a highly relevant clinical domain in the care of patients with schizophrenia that also has distinct relationships with some other known traits of the disease. Trait depression may be an important contributor to the clinical heterogeneity of schizophrenia.

A longitudinal study of cognitive functioning in schizophrenia: clinical and biological predictors

BACKGROUND

Cognitive deficits are a central feature of schizophrenia but it is not certain how cognitive functioning changes over time. The purpose of this prospective longitudinal study was to determine the temporal change of cognitive functioning and the predictors of cognitive performance from among demographic, clinical, and biological variables.

METHODS

Participants were individuals with schizophrenia or schizoaffective disorder whose cognitive functioning was assessed at multiple time points with the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). At the baseline visit participants had a blood sample drawn from which C-reactive protein, antibodies to Herpes Simplex Virus type 1, and selected genetic polymorphisms were measured. Repeated measures linear regression was used to determine whether cognitive measures changed over time and which variables predicted cognitive performance.

RESULTS

The sample consisted of 132 participants, mean age 43.7 years at baseline, who received a median of 3 cognitive assessments over a period averaging 2.8 years. The RBANS Total score and Language index showed no statistically significant temporal change; performance on two indices, Immediate Memory and Attention, showed modest but statistically significant improvements (gains of 0.89±0.33 and 0.76±0.29 points per year, respectively); Visuospatial/Constructional performance showed a modest but statistically significant decline (of 0.80±0.25 points per year). Few variables predicted cognitive performance; however greater psychiatric symptom severity was associated with worse cognitive performance for most cognitive measures.

CONCLUSIONS

Cognitive functioning in middle-aged persons with schizophrenia showed an absence of decline for most measures and modest gains in some measures.

Clozapine and visuospatial processing in treatment-resistant schizophrenia

INTRODUCTION

Clozapine, the most widely used option in treatment-resistant schizophrenia, has been shown to be superior to other antipsychotic medications in improving cognitive function in patients. However, the results have not been consistent and the mechanisms underlying this effect have not been elucidated. Thus, the purpose of the present study was to evaluate verbal and nonverbal cognition (using visuospatial processing tests) in patients treated with clozapine (initially treatment resistant) and those treated with other second-generation antipsychotics, relative healthy control subjects. Furthermore, we examined neural correlates of visuospatial processing in the three groups.

METHODS

Twenty schizophrenia patients treated with clozapine (TR-C group), 23 patients stabilised with atypical antipsychotics other than clozapine (NTR group), and 21 healthy control participants completed a battery of verbal and visuospatial cognitive tests. In addition, participants underwent functional magnetic resonance imaging (fMRI) while performing one of the visuospatial tests (the mental rotation task). The fMRI data were analysed separately in each group using Statistical Parametric Mapping software (SPM5).

RESULTS

Overall, schizophrenia patients exhibited deficit on verbal and nonverbal processing relative to the healthy controls, but we observed some interesting differences between the two groups of patients. Specifically, the NTR group performed better than the TR-C group on the Block Design and the Raven's Progressive Matrices. With respect to brain function during mental rotation, the NTR group showed significant activations in regions of the temporal and occipital cortex, whereas the TR-C patients did not. The relative deactivations associated with the task were also more robust in NTR compared to the other group of patients, despite a similar performance.

CONCLUSION

Present results suggest better visuospatial processing in the NTR relative to the TR-C group. This difference could be attributed to the treatment resistance itself or a lack of beneficial effect of clozapine relative to other atypical antipsychotics in ameliorating nonverbal abilities. Future studies of the relationship between clozapine and cognition, as well as between treatment resistance and cognition, are warranted.

Can cognitive deficits differentiate between schizophrenia with and without obsessive-compulsive symptoms?

BACKGROUND

The frequent occurrence of obsessive-compulsive symptoms (OCS) in the course of schizophrenia and their impact on the functional outcome of the illness underlie the suggestion that the presence of OCS represents a separate subtype of schizophrenia, with a distinct clinical presentation and prognosis and specific neurobiological characteristics. This study investigated whether the presence of OCS in schizophrenia is associated with worse cognitive functioning in the domains of processing speed, executive functions and visuospatial memory. We also explored whether the degree of impairment in any of these cognitive domains could predict group membership (i.e. Schizophrenia with OCS [Sch-OCS] and Schizophrenia without OCS) and if there was a relationship between cognitive functioning and severity of OCS within the Sch-OCS group.

METHODS

Forty patients with schizophrenia, 20 with and 20 without OCS, individually matched for age, gender, years of education and severity of psychotic symptoms and 20 healthy controls underwent a comprehensive neuropsychological assessment.

RESULTS

Only lower performance in processing speed discriminated patients with OCS from patients without OCS. Processing speed impairment not only classified patients in OCS or non-OCS group but was also independent of the severity of OCS symptoms.

CONCLUSIONS

The notion of additive effects of both schizophrenia and OCD on the structural and functional integrity of the brain circuits that support cognitive functions warrants further investigation in longitudinal neuropsychological and neuroimaging studies with larger samples and sufficient variation in the severity of OCS.

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.

Attention/processing speed prospectively predicts social impairment 18 years later in mood disorders

Cross-sectional studies suggest that cognitive deficits contribute to psychosocial impairment among individuals with mood disorders. However, studies examining whether cognition prospectively predicts psychosocial outcome are few, have used short follow-up periods, and have not demonstrated incremental validity (i.e., that cognition predicts future functioning even when controlling for baseline functioning). In a sample of 51 individuals with unipolar depression or bipolar disorder, we investigated whether attention/processing speed (APS) performance predicted social functioning 18 years later. Baseline APS predicted 18-year social functioning even after controlling for baseline social functioning and depressive symptoms, demonstrating incremental validity. Individuals with high baseline APS had stable social functioning over 18 years, whereas functioning deteriorated among those with low APS. This finding helps clarify the temporal order of cognitive and psychosocial deficits associated with mood disorders and suggests the clinical utility of cognitive measures in identifying those at risk of deterioration in social functioning.