Neurocognition in patients with psychotic and non-psychotic bipolar I disorder. A comparative study with individuals with schizophrenia

Verbal fluency in schizophrenia and bipolar disorder - A longitudinal, family study

Verbal fluency (VF) has been proposed as a putative neurocognitive endophenotype in schizophrenia (SZ) and bipolar disorder (BD). However, this hypothesis has not been examined using a longitudinal family approach. We conducted a five-group, comparative study. The sample comprised 323 adult participants, including 81 BD patients, 47 unaffected relatives of BD BD-Rel), 76 SZ patients, 40 unaffected relatives of SZ (SZ-Rel), and 79 genetically unrelated healthy controls (HC). All subjects were assessed twice with semantic VF (sem-VF) and phonological VF (ph-VF) tests over a 2-year follow-up period. ANCOVAs controlling for age and years of education were used to compare performance across groups. Patients with SZ and BD and their unaffected relatives showed sem-VF and ph-VF deficits at baseline, which persisted over time (all, p < 0.05). Moreover, BD-Rel showed an intermediate performance between SZ and HC. A repeated-measures ANOVA revealed no significant differences in the between-group trajectories comparison (p > 0.05). Our findings support that VF may represent a neurocognitive endophenotype for SZ and BD. Further longitudinal, family studies are warranted to confirm this preliminary evidence.

Processing speed and sustained attention in bipolar disorder and major depressive disorder: A systematic review and meta-analysis

OBJECTIVES

Cognitive impairment is a core feature of bipolar disorder (BD) and major depressive disorder (MDD). Deficits in processing speed (PS) and sustained attention (SA) may be particularly impaired and may underpin a broader profile of deficits, however current knowledge of the nature of these impairments is limited by heterogeneous results in the literature. Few reviews to date have attempted to disentangle sources of heterogeneity to assess the presence and magnitude of impairments in PS and SA in BD and MDD.

METHODS

One hundred and three studies were reviewed to examine performance in tests of PS and SA in BD (n = 3452) and MDD (n = 5461) compared to healthy controls (n = 8016). Neuropsychological methodology used in the literature was summarised. Data were meta-analysed to assess impairments in PS and SA for each neuropsychological test separately. Subgroup analysis was performed across mood states to investigate sources of heterogeneity.

RESULTS

Impairments were found across most neuropsychological tests, with small to large effect sizes for BD (range: d = 0.19-0.96) and MDD (range: d = 0.29-0.86). Impairments were present in symptomatic states and euthymia in most cases. Some outcome measures were not impaired in euthymia. Heterogeneity was observed for most neuropsychological tests and remained after separating by mood state. There inadequate data to meta-analyse some outcome measures, particularly for symptomatic groups.

CONCLUSION

Impairments in PS and SA in BD and MDD can be observed across most neuropsychological tests. Future research should further investigate the nature of these impairments across mood states, controlling for clinical confounds.

Verbal memory impairments in mood disorders and psychotic disorders: A systematic review of comparative studies

BACKGROUND

Mood and psychotic disorders are both associated with verbal memory impairments. Verbal memory represents an important treatment target for both disorders. However, whether the neurocognitive and neurophysiological profiles of verbal memory impairments differ between specific disorders within these two diagnostic categories and healthy controls remains unclear. The current systematic review synthesized findings from comparative studies which used behavioural and neuroimaging tasks to investigate verbal memory impairments between: (1) mood disorder, psychotic disorder, and healthy control groups; and (2) mood disorder without psychotic features, mood disorder with psychotic features, and healthy control groups.

METHODS

The search strategy combined terms related to three main concepts: 'mood disorders', 'psychotic disorders', and 'verbal memory'. Searches were executed in Embase, MEDLINE, PsycInfo, and PubMed databases. A total of 38 articles met the full eligibility criteria and were included in the final narrative synthesis. Findings were stratified by memory domain (overall composite score, verbal working memory, immediate recall, delayed recall, and recognition memory) and by illness phase (acute and non-acute).

RESULTS

Mood and psychotic disorders displayed consistent verbal memory impairments compared to healthy controls during the acute and non-acute phases. Few significant differences were identified in the literature between mood and psychotic disorders, and between mood disorders with and without psychotic features. Individuals with schizophrenia were found to have decreased immediate and delayed verbal recall performance compared to bipolar disorder groups during the acute phase. Major depressive disorder groups with psychotic features were also found to have decreased delayed verbal recall performance compared to those without psychosis during the acute phase. No consistent differences were identified between mood and psychotic disorders during the non-acute phase. Finally, preliminary evidence suggests there may be functional abnormalities in important frontal and temporal brain regions related to verbal memory difficulties in both mood and psychotic disorders.

DISCUSSION

The current findings have potential implications for the diagnosis and treatment of cognitive impairments in mood and psychotic disorders. Verbal recall memory may serve as a sensitive tool in the risk stratification of cognitive impairments for certain mood and psychotic disorders. Moreover, since no widespread differences between clinical groups were identified, the evidence supports providing targeted interventions for verbal memory, such as pharmacological and non-pharmacological interventions, through a trans-diagnostic approach in mood and psychotic disorders.

Factors associated with suicide attempts in the antecedent illness trajectory of bipolar disorder and schizophrenia

BACKGROUND

Factors associated with suicide attempts during the antecedent illness trajectory of bipolar disorder (BD) and schizophrenia (SZ) are poorly understood.

METHODS

Utilizing the Rochester Epidemiology Project, individuals born after 1985 in Olmsted County, MN, presented with first episode mania (FEM) or psychosis (FEP), subsequently diagnosed with BD or SZ were identified. Patient demographics, suicidal ideation with plan, self-harm, suicide attempts, psychiatric hospitalizations, substance use, and childhood adversities were quantified using the electronic health record. Analyses pooled BD and SZ groups with a transdiagnostic approach given the two diseases were not yet differentiated. Factors associated with suicide attempts were examined using bivariate methods and multivariable logistic regression modeling.

RESULTS

A total of 205 individuals with FEM or FEP (BD = 74, SZ = 131) were included. Suicide attempts were identified in 39 (19%) patients. Those with suicide attempts during antecedent illness trajectory were more likely to be female, victims of domestic violence or bullying behavior, and have higher rates of psychiatric hospitalizations, suicidal ideation with plan and/or self-harm, as well as alcohol, drug, and nicotine use before FEM/FEP onset. Based on multivariable logistic regression, three factors remained independently associated with suicidal attempts: psychiatric hospitalization (OR = 5.84, 95% CI 2.09-16.33, p < 0.001), self-harm (OR = 3.46, 95% CI 1.29-9.30, p = 0.014), and nicotine use (OR = 3.02, 95% CI 1.17-7.76, p = 0.022).

CONCLUSION

Suicidal attempts were prevalent during the antecedents of BD and SZ and were associated with several risk factors before FEM/FEP. Their clinical recognition could contribute to improve early prediction and prevention of suicide during the antecedent illness trajectory of BD and SZ.

The role of semantic clustering in the relationship between verbal memory and psychosocial functioning in schizophrenia and bipolar disorder: Possible distinct cognitive pathway compared to healthy controls

BACKGROUND

Verbal memory (VM) is impaired in schizophrenia (SZ) and bipolar disorder (BD), and predicts psychosocial functioning. However, there is a lack of research exploring the role of VM component processes, including semantic clustering, in these disorders. Semantic clustering might impact this association, as effective semantic memory strategies may reflect unimpaired executive control, leading to an adequate functioning. We aimed to investigate VM components in SZ and BD, and the role of semantic clustering in the relationship between VM and functioning.

METHODS

We included 495 participants (156 SZ, 172 BD, and 167 healthy controls (HC)) that underwent an assessment using the Hopkins Verbal Learning Test - Revised for VM and the Functioning Assessment Short Test for psychosocial functioning. We compared groups through ANOVAs and investigated the effect of semantic clustering in the relationship between VM total immediate free recall and functioning through linear regression models.

RESULTS

SZ had worse overall VM performance compared to BD, which performed worse than HCs. HCs used more semantic clustering than SZ and BD, but there were no differences between the two clinical groups. In HCs, semantic clustering impacted the relationship between VM performance and functioning, while no interaction was observed in SZ or BD.

LIMITATIONS

Cross-sectional design; no medication effects or other cognitive functions were assessed.

CONCLUSIONS

SZ and BD may use an alternative cognitive pathway in which the relationship between VM and functioning is independent of complex cognitive processes such as semantic clustering, supporting the cognitive remediation targeting of VM in these disorders.

Differences of resting fMRI and cognitive function between drug-naïve bipolar disorder and schizophrenia

BACKGROUND

Bipolar disorder (BD) and schizophrenia (SC) have many similarities in clinical manifestations. The acute phase of BD has psychotic symptoms, while SC also has emotional symptoms during the onset, which suggests that there is some uncertainty in distinguishing BD and SC through clinical symptoms.

AIM

To explore the characteristics of brain functional activities and cognitive impairment between BD and SC.

METHODS

Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) test was performed on patients in drug-naïve BD and SC (50 subjects in each group), and resting-state functional magnetic resonance imaging (rs-fMRI) scanning was performed meanwhile. Rs-fMRI data were routinely preprocessed, and the value of the fractional amplitude of low-frequency fluctuation (fALFF) was calculated. Then each part of the scores of the RBANS and the characteristics of brain function activities were compared between the two groups. Finally used Pearson correlation to analyze the correlation between cognition and brain function.

RESULTS

(1) Compared with BD group, all parts of RBANS scores in SC group decreased; (2) The left inferior occipital gyrus (IOG, peak coordinates - 30, -87, -15; t = 4.78, voxel size = 31, Alphasim correction) and the right superior temporal gyrus (STG, peak coordinates 51, -12, 0; t = 5.08, voxel size = 17, AlphaSim correction) were the brain areas with significant difference in fALFF values between BD and SC. Compared with SC group, the fALFF values of the left IOG and the right STG in BD group were increased (p < 0.05); (3) Pearson correlation analysis showed that the visuospatial construction score was positively correlated with the fALFF values of the left IOG and the right STG (r_{left IOG} = 0.304, p = 0.003; r_{right STG} = 0.340, p = 0.001); The delayed memory (figure recall) score was positively correlated with the fALFF value of the left IOG (r_{left IOG} = 0.207, p = 0.044).

DISCUSSION

The cognitive impairment of SC was more serious than BD. The abnormal activities of the left IOG and the right STG may be the core brain region to distinguish BD and SC, and are closely related to cognitive impairment, which provide neuroimaging basis for clinical differential diagnosis and explore the pathological mechanism of cognitive impairment.

The mood disorder spectrum vs. schizophrenia decision tree: EDIPHAS research into the childhood and adolescence of 205 patients

BACKGROUND

The early detection of patients at risk of developing schizophrenia and bipolar disorder, and more broadly mood spectrum disorder, is a public health concern. The phenotypical overlap between the prodromes in these disorders calls for a simultaneous investigation into both illness trajectories.

METHOD

This is an epidemiological, retrospective, multicentre, descriptive study conducted in the Grand-Est region of France in order to describe and compare early symptoms in 205 patients: 123 of which were diagnosed with schizophrenia and 82 with bipolar disorder or mood spectrum disorder. Data corresponding to the pre-morbid and prodromal phases, including a timeline of their onset, were studied in child and adolescent psychiatric records via a data grid based on the literature review conducted from birth to 17 years of age.

RESULTS

Two distinct trajectories were highlighted. Patients with schizophrenia tended to present more difficulties at each developmental stage, with the emergence of negative and positive behavioural symptoms during adolescence. Patients with mood spectrum disorder, however, were more likely to exhibit anxiety and then mood-related symptoms. Overall, our results corroborate current literature findings and are consistent with the neurodevelopmental process. We succeeded in extracting a decision tree with good predictability based on variables relating to one diagnosis: 77.6% of patients received a well-indexed diagnosis. An atypical profile was observed in future mood spectrum disorder patients as some exhibited numerous positive symptoms alongside more conventional mood-related symptoms.

CONCLUSION

The combination of all these data could help promote the early identification of high-risk patients thereby facilitating early prevention and appropriate intervention in order to improve outcomes.

Neurocognition, functional outcome, and quality of life in remitted and non-remitted schizophrenia: A comparison with euthymic bipolar I disorder and a control group

There are discrepancies about if the severity of the symptomatology in schizophrenia is related to neurocognitive performance, functional outcome, and quality of life (QoL). Also, there are controversial data about the comparison between euthymic bipolar patients and different subgroups of schizophrenia in neurocognition, functioning, and QoL level. The present study aimed to compare the neurocognitive performance, functional outcome, and QoL of remitted and non-remitted patients with SC with respect to a group of euthymic patients with BD, and a control group. It included 655 subjects: 98 patients with schizophrenia in remission (SC-R), 184 non-remitted patients with schizophrenia (SC-NR), 117 euthymic patients with bipolar I disorder (BD), and 256 healthy subjects. A comprehensive clinical, neurocognitive (six cognitive domains), functional, and QoL assessment was carried out. Remission criteria of Andreasen were used to classify schizophrenia patients as remitted or non-remitted. Compared with control subjects all groups of patients showed impaired neurocognitive performance, functioning and QoL. SC-R patients had an intermediate functioning between control subjects and SC-NR, all at a neurocognitive, functional, or QoL level. There were no significant differences between SC-R and BD. These results suggest that reaching clinical remission is essential to achieve a better level of psychosocial functioning, and QoL. Likewise, the results of this study suggest that euthymic patients with bipolar disorder and patients with schizophrenia in remission are comparable at the neurocognitive and functional levels, which might have implications in the pathophysiology of both disorders.

Akt-mTOR hypoactivity in bipolar disorder gives rise to cognitive impairments associated with altered neuronal structure and function

The Akt family of kinases exerts many of its cellular effects via the activation of the mammalian target of rapamycin (mTOR) kinase through a series of intermediary proteins. Multiple lines of evidence have identified Akt-family kinases as candidate schizophrenia and bipolar disorder genes. Although dysfunction of the prefrontal cortex (PFC) is a key feature of both schizophrenia and bipolar disorder, no studies have comprehensively assessed potential alterations in Akt-mTOR pathway activity in the PFC of either disorder. Here, we examined the activity and expression profile of key proteins in the Akt-mTOR pathway in bipolar disorder and schizophrenia homogenates from two different PFC subregions. Our findings identify reduced Akt-mTOR PFC signaling in a subset of bipolar disorder subjects. Using a reverse-translational approach, we demonstrated that Akt hypofunction in the PFC is sufficient to give rise to key cognitive phenotypes that are paralleled by alterations in synaptic connectivity and function.

Altered Risk-Taking Behavior in Early-Stage Bipolar Disorder With a History of Psychosis

Altered risk-taking propensity is an important determinant of functional impairment in bipolar disorder. However, prior studies primarily assessed patients with chronic illness, and risk-taking has not been evaluated in the early illness course. This study investigated risk-taking behavior in 39 euthymic early-stage bipolar disorder patients aged 16-40 years who were treated within 3 years from their first-episode mania with psychotic features and 36 demographically-matched healthy controls using the Balloon Analog Risk Task (BART), a well-validated risk-taking performance-based paradigm requiring participants to make responses for cumulative gain at increasing risk of loss. Relationships of risk-taking indices with symptoms, self-reported impulsivity, cognitive functions, and treatment characteristics were also assessed. Our results showed that patients exhibited significantly lower adjusted scores (i.e., average balloon pumps in unexploded trials) (p = 0.001), lower explosion rate (p = 0.007) and lower cumulative scores (p = 0.003) than controls on BART, indicating their suboptimal risk-taking performance with increased propensity for risk aversion. Risk-taking indices were not correlated with any symptom dimensions, self-reported impulsivity, cognitive functions or antipsychotic dose. No significant difference was observed between patients with and without antipsychotic medications on self-reported impulsivity or any of the BART performance indices. This is the first study to examine risk-taking behavior in early-stage bipolar disorder with history of psychosis and indicates that patients displayed altered risk-taking with increased risk aversion compared with controls. Further research is needed to clarify longitudinal trajectory of risk-taking propensity and its relationships with psychosis and functional outcome in the early stage of bipolar disorder.

Cognitive Outcomes for Essential Tremor Patients Selected for Thalamic Deep Brain Stimulation Surgery Through Interdisciplinary Evaluations

Objective: Deep brain stimulation (DBS) targeted to the ventral intermediate (VIM) nucleus of the thalamus is effective for motor symptoms in essential tremor (ET), but there is limited data on cognitive outcomes. We examined cognitive outcomes in a large cohort of ET DBS patients (pre-DBS and 1+ year after DBS).

Methods: In a retrospective analysis, we used repeated-measures ANOVA testing to examine whether the age of tremor onset, age at DBS surgery, hemisphere side implanted with lead, unilateral vs. bilateral implantations, and presence of surgical complications influenced the cognitive outcomes. Neuropsychological outcomes of interest were verbal memory, executive functioning, working memory, language functioning, visuospatial functioning, and general cognitive function.

Results: We identified 50 ET DBS patients; 29 (58%) males; the mean age of tremor onset was 35.84 (±21.50) years with a median age of 38 years. The mean age at DBS was 68.18 (±10.07) years. There were 37 unilateral 30 left, seven right, and 13 bilateral brain implantations. In the subgroup analysis, there was a significant interaction between assessment (pre vs. post) and age of tremor onset (<38 vs. >38 years); F_(1,30) = 4.47; p = 0.043 for working memory. The post hoc testing found improvements for younger onset ET. Similarly, there was a significant interaction between assessment (pre vs. post) and complications vs. no complications subgroups; F_(1,45) = 4.34; p = 0.043 for verbal memory with worsening scores seen for ET patients with complications. The remaining tests were not significant.

Conclusion: In this large cohort of ET patients with (>30% improvements), DBS was not accompanied by a significant decline in many cognitive domains. These outcomes were possibly related to the selection of patients with normal cognitive functioning before surgery, unilateral DBS implantations for the majority, and selection of patients with optimal response to DBS.

Distinct Associations of Cognitive Impairments and Reduced Gray Matter Volumes in Remitted Patients with Schizophrenia and Bipolar Disorder

Background

Cognitive impairments are documented in schizophrenia (SZ) and bipolar disorder (BD) and may be related to gray matter volumes (GMVs). Thus, this study is aimed at exploring whether the association between cognitive impairments and GMV alterations is similar in patients with SZ and BD and understanding the underlying neurobiological mechanisms.

Methods

A total of 137 adult subjects (46 with SZ, 35 with BD, and 56 age-, sex-, and education-matched healthy controls (HC)) completed the MATRICS Consensus Cognitive Battery (MCCB) and structural magnetic resonance imaging scanning. We performed group comparisons of the cognitive impairments, the GMV alterations, and the association between them.

Results

Compared with HC, the patients with SZ and BD showed shared deficits in 4 cognitive domains (i.e., processing speed, working memory, problem solving, and social cognition) and the composite. SZ and BD had commonly decreased GMVs, mainly in the insula, superior temporal pole, amygdala, anterior cingulate, and frontal cortices (superior, middle, opercular inferior, and orbital frontal gyrus). No correlation between MCCB scores and GMVs was detected in SZ. However, for BD, working memory was relevant to the right hemisphere (i.e., right insula, amygdala, superior temporal pole, and medial and dorsolateral superior frontal gyrus). Limitations. The major limitations were that not all patients were the first-episode status and no medication.

Conclusions

The association was mainly limited to the BD group. Thus, the underlying pathophysiology of the cognitive deficits, in terms of GMV alterations, may be diverse between two disorders.

Cognition in offspring of parents with psychotic and non-psychotic severe mental illness

BACKGROUND

Cognitive impairment is a feature of severe mental illness (SMI; schizophrenia, bipolar disorder, major depressive disorder). Psychotic forms of SMI may be associated with greater cognitive impairment, but it is unclear if this differential impairment pre-dates illness onset or whether it reflects a consequence of the disorder. To establish if there is a developmental impairment related to familial risk of psychotic SMI, we investigated cognition in offspring of parents with psychotic and non-psychotic SMI.

METHOD

Participants included 360 children and youth (mean age 11.10, SD 4.03, range 6-24), including 68 offspring of parents with psychotic SMI, 193 offspring of parents with non-psychotic SMI, and 99 offspring of control parents. The cognitive battery assessed a range of functions using standardized tests and executive function tasks from the Cambridge Automated Neuropsychological Test Battery.

RESULTS

Compared to controls, offspring of parents with psychotic SMI performed worse on overall cognition (β = -0.32; p < 0.001) and 6 of 15 cognitive domains, including verbal intelligence, verbal working memory, processing speed, verbal learning and memory, verbal fluency, and sustained attention. Offspring of parents with non-psychotic SMI performed worse than controls on 3 of the 15 domain specific cognitive tests, including verbal intelligence, visual memory and decision-making.

CONCLUSIONS

Widespread mild-to-moderate cognitive impairments are present in young offspring at familial risk for transdiagnostic psychotic SMI. Offspring at familial risk for non-psychotic SMI showed fewer and more specific impairments in the domains of verbal intelligence, visual memory and decision-making.

Distinguishing patterns of impairment on inhibitory control and general cognitive ability among bipolar with and without psychosis, schizophrenia, and schizoaffective disorder

BACKGROUND

Deficits in inhibitory control on a Stop Signal Task (SST) were previously observed to be of similar magnitude across schizophrenia, schizoaffective, and bipolar disorder with psychosis, despite variation in general cognitive ability. Understanding different patterns of performance on the SST may elucidate different pathways to the impaired inhibitory control each group displayed. Comparing nonpsychotic bipolar disorder to the psychosis groups on SST may also expand our understanding of the shared neurobiology of this illness spectrum.

METHODS

We tested schizophrenia (n = 220), schizoaffective (n = 216), bipolar disorder with (n = 192) and without psychosis (n = 67), and 280 healthy comparison participants with a SST and the Brief Assessment of Cognition in Schizophrenia (BACS), a measure of general cognitive ability.

RESULTS

All patient groups had a similar degree of impaired inhibitory control over prepotent responses. However, bipolar groups differed from schizophrenia and schizoaffective groups in showing speeded responses and inhibition errors that were not accounted for by general cognitive ability. Schizophrenia and schizoaffective groups had a broader set of deficits on inhibition and greater general cognitive deficit, which fully accounted for the inhibition deficits. No differences were found between the clinically well-matched bipolar with and without psychosis groups, including for inhibitory control or general cognitive ability.

CONCLUSIONS

We conclude that 1) while impaired inhibitory control on a SST is of similar magnitude across the schizo-bipolar spectrum, including nonpsychotic bipolar, different mechanisms may underlie the impairments, and 2) history of psychosis in bipolar disorder does not differentially impact inhibitory behavioral control or general cognitive abilities.

Predictive factors of functional outcome in patients with bipolar I disorder: a five-year follow-up

BACKGROUND

Functional impairment is commonly encountered among patients with bipolar disorder (BD) during periods of remission. The distribution of the impairment of the functional outcome is heterogeneous. The objective of this current investigation was to identify neurocognitive and clinical predictors of psychosocial functioning in a sample of patients with BD.

METHODS

Seventy-six patients (59.2% females) and 40 healthy controls (50% females), aged 18 to 55 years, were assessed using a comprehensive neurocognitive battery (six neurocognitive domains), and the Functioning Assessment Short Test (FAST), at baseline and after a 5-year follow-up. Stepwise regression models were used to identify predictor variables related to psychosocial functioning.

RESULTS

The number of hospitalizations during the follow-up, the change occurred in the neurocognitive composite index (NCI change), and NCI at baseline explained 30.8% of the variance of functioning. The number of hospitalizations during the follow-up was the variable that explained a greater percentage of the variance (16.9%). Verbal memory at baseline and the change in sustained attention during the follow-up explained 10% and 5.9% of the variance of the psychosocial functioning, respectively.

LIMITATIONS

The interval of 5 years between the two assessments could be too short to detect a possible progression in functional outcome for the overall sample.

CONCLUSIONS

The clinical course during the follow-up is the factor that has a greater impact on psychosocial functioning in patients with BD. Thus, the interventions aimed to promote prevention of relapses should be considered as essential for avoiding functional impairment in these patients.

120th Anniversary of the Kraepelinian Dichotomy of Psychiatric Disorders

PURPOSE OF REVIEW

Emil Kraepelin, in 1899, proposed a dichotomy of psychiatric disorders into "dementia praecox," further called schizophrenia, and "manisch-depressives Irresein," now conceptualized as a bipolar disorder. The purpose of the review is to show both similarities and differences between disorders involved in this dichotomy, speaking for and against the idea.

RECENT FINDINGS

On the molecular genetic side, there are data for both a genetic overlap and genetic differences between these two illnesses. Among pharmacological treatment, lithium, valproates, and carbamazepine present evidence for Kraepelinian dichotomy while atypical antipsychotics speak against this. The recent results for similarities and differences in the immune system, cognitive functions, and neurodevelopmental mechanisms have also been presented and discussed. As of 2019, the Kraepelinian dichotomy has been still partly valid although the results of recent clinical, neurobiological, and pharmacological studies provided a large number of data for an intermediate space between schizophrenia and bipolar disorder.

Working Memory Impairment Across Psychotic disorders

BACKGROUND

Working memory (WM) has been a central focus of cognitive neuroscience research because WM is a resource that is involved in many different cognitive operations. The goal of this study was to evaluate the clinical utility of WM paradigms developed in the basic cognitive neuroscience literature, including methods designed to estimate storage capacity without contamination by lapses of attention.

METHODS

A total of 61 people with schizophrenia, 49 with schizoaffective disorder, 47 with bipolar disorder with psychosis, and 59 healthy volunteers were recruited. Participants received multiple WM tasks, including two versions each of a multiple Change Detection paradigm, a visual Change Localization paradigm, and a Running Span task.

RESULTS

Healthy volunteers performed better than the combined patient group on the visual Change Localization and running span measures. The multiple Change Detection tasks provided mixed evidence about WM capacity reduction in the patient groups, but a mathematical model of performance suggested that the patient groups differed from controls in their rate of attention lapsing. The 3 patient groups performed similarly on the WM tasks. Capacity estimates from the Change Detection and Localization tasks showed significant correlations with functional capacity and functional outcome.

CONCLUSIONS

The patient groups generally performed in a similarly impaired fashion across tasks, suggesting that WM impairment and attention lapsing are general features of psychotic disorders. Capacity estimates from the Change Localization and Detection tasks were related to functional capacity and outcome, suggesting that these methods may be useful in a clinical context.

Impact of number of episodes on neurocognitive trajectory in bipolar disorder patients: a 5-year follow-up study

BACKGROUND

The neurocognitive trajectory in bipolar disorder (BD) is variable, with controversial findings, and most evidence come from cross-sectional studies. We aimed to examine the course of neurocognitive functioning in a sample of euthymic BD patients in comparison with a control group during a 5-year follow-up.

METHODS

Ninety-nine euthymic bipolar patients and 40 healthy controls were assessed using a comprehensive neurocognitive battery (six neurocognitive domains) at baseline (T1) and then at 5-year follow-up (T2) in a longitudinal study.

RESULTS

No evidence of a progression in neurocognitive dysfunction was found either in cognitive composite index or in any of the neurocognitive domains for the whole cohort. However, there was a negative correlation between number of manic episodes and hospitalisations due to manic episodes and change in neurocognitive composite index (NCI) during the follow-up. Moreover, patients with higher number of manic and hypomanic episodes have a greater decrease in NCI, working memory and visual memory. History of psychotic symptoms was not related to the trajectory of neurocognitive impairment.

CONCLUSIONS

Our results suggest that, although the progression of cognitive decline is not a general rule in BD, BD patients who have a greater number of manic or hypomanic episodes may constitute a subgroup characterised by the progression of neurocognitive impairment. Prevention of manic and hypomanic episodes could have a positive impact on the trajectory of cognitive function.

Neurocognition and functional outcome in patients with psychotic, non-psychotic bipolar I disorder, and schizophrenia. A five-year follow-up

Background:

Bipolar disorder (BD) and schizophrenia (SZ) are characterized by neurocognitive and functional deficits with marked heterogeneity. It has been suggested that BD with a history of psychotic symptoms (BD-P) could constitute a phenotypically homogeneous subtype characterized by greater neurocognitive and functional impairments, or by a distinct trajectory of such deficits. The aim of this study was to compare the neurocognitive and functional course of euthymic BD-P, euthymic BD patients without a history of psychosis (BD-NP), stabilized patients with schizophrenia and healthy subjects, during a five-year follow-up.

Methods:

Neurocognitive and psychosocial function was examined in 100 euthymic patients with BD (50 BD-P, 50 BD-NP), 50 stabilized patients with schizophrenia (SZ), and 51 healthy controls (HC) at baseline (T1), and after a 5-year follow-up (T2).

Results:

The course of both neurocognitive performance and functional outcome of patients with SZ and BD (BD-P and BD-NP) is stable. The profile of neurocognitive impairment of patients with SZ or BD (BD-P and BD-NP), is similar, with only quantitative differences circumscribed to certain domains, such as working memory. The subgroup of patients with BD-NP does not show functional deterioration.

Conclusions:

We have not found evidence of progression in the neurocognitive or psychosocial impairment in any of the three groups of patients, although it cannot be dismissed the possibility of a subset of patients with a progressive course. Other longitudinal studies with larger samples and longer duration are necessary to confirm these findings.

Cognitive Deficits in Psychotic Disorders: A Lifespan Perspective

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

Psychosocial functioning in patients with psychotic and non-psychotic bipolar I disorder. A comparative study with individuals with schizophrenia

BACKGROUND

More than 50% of individuals with bipolar disorder (BD) do not reach full psychosocial functioning, even during periods of euthymia. It has been suggested that history of psychotic symptoms is one of the factors which are associated with a worse functional outcome. The objective was to compare psychosocial functioning between patients with BD, with (BD-P), and without (BD-NP) a history of psychotic symptoms, and to examine whether the history of psychotic symptoms, or other clinical or neurocognitive variables predict psychosocial functioning.

METHODS

Psychosocial functioning and neurocognition were examined in 100 euthymic patients with bipolar I disorder (50 BD-P, and 50 BD-NP), compared to 50 stabilised patients with schizophrenia (SZ), and 51 healthy controls (HC).

RESULTS

1) There were no differences between BD-P and BD-NP in the GAF-F score or in the FAST total score. 2) The two groups of patients with BD had better scores than SZ both in the GAF-F, and in all measures of the FAST, except for the subscale leisure time. 3) The neurocognitive composite index, verbal memory and subclinical depressive symptoms were the variables which explained a higher percentage of the variance of functional outcome.

LIMITATIONS

The cross-sectional design, and the relatively small sample size are the main limitations.

CONCLUSIONS

A history of psychotic symptoms has no relevant impact on the level of psychosocial functioning in BD. Neurocognitive dysfunction and subclinical depressive symptoms are the variables that best explain the functional impairment. These findings have important clinical implications.

Neurocognitive features in clinical subgroups of bipolar disorder: A meta-analysis

OBJECTIVE

There is a significant cognitive heterogeneity in bipolar disorder (BD). The aim of this systematic review was to examine the potential distinctive neuropsychological of features of clinical subgroups of BD. A literature search investigating cognitive differences between potential subtypes of BD was conducted.

METHODS

It was possible to conduct a meta-analysis of studies investigating the relationship between cognitive deficits and subgroups of DSM-IV BD (type I (BD-I) and type II (BD-II)), subgroups based on history of psychosis (PBD and NPBD). The cognitive domains investigated in this meta-analysis included verbal memory, visual memory, processing speed, executive functions speed (EF-speed), EF-accuracy, attention, working memory, social cognition. Current meta-analysis included 48 reports and compared cognitive performances of 1211 BD-I and 836 BD-II patients. It also compared cognitive functioning in 1017 PBD and 744 NPBD patients.

RESULTS

Both history of psychosis (d = 0.19) and BD-I (d = 0.17) diagnosis were associated with modestly more pronounced global cognitive impairment. In specific domains, BD-I significantly underperformed BD-II in verbal memory, processing speed, EF-speed, EF-accuracy (d = 0.15-0.26). PBD was associated with significantly impaired cognition compared to NPBD in verbal memory, processing speed, EF-speed, EF-accuracy, working memory and social cognition (d = 0.12-0.28).

CONCLUSION

In BD, history of psychosis and full-manic episode are modestly associated with increased cognitive deficits. Neurocognitive differences between clinical subtypes of BD are quite subtle and are not distinctive. Furthermore, other factors reflecting differences in illness severity can explain observed between-group differences. Most of the cognitive heterogeneity in BD cannot be explained by proposed subtypes of BD.

Sustaining attention to simple visual tasks: a central deficit in schizophrenia? A systematic review

Impairments in sustained attention, that is, the ability to achieve and maintain the focus of cognitive activity on a given stimulation source or task, have been described as central to schizophrenia. Today, sustained attention deficit is still considered as a hallmark of schizophrenia. Nevertheless, current findings on this topic are not consistent. To clarify these findings, we attempt to put these results into perspective according to the type of assessment (i.e., overall and over time assessment), the participants' characteristics (i.e., clinical and demographic characteristics), and the paradigms (i.e., traditionally formatted tasks, go/no-go tasks, and the sustained attention task) and measures used. Two types of assessment lead to opposite findings; they do not evaluate sustained attention the same way. Studies using overall assessments of sustained attention ability tend to reveal a deficit, whereas studies using over time assessments do not. Therefore, further research is needed to investigate the underlying cognitive control mechanisms of changes in sustained attention in schizophrenia.