Persistence of cognitive impairment and its negative impact on psychosocial functioning in lithium-treated, euthymic bipolar patients: a 6-year follow-up study

Cognition in Euthymic Patients with Bipolar Disorder: Do Not Forget to Account for Anxiety!

Purpose

Despite the high prevalence of anxiety disorders in BD and its known impact on cognitive performance, the presence and severity of anxious symptoms is not systematically evaluated in studies on cognition in BD. Our aim was to determine if attention and/or inhibition of cognitive interference in euthymic patients with type I Bipolar Disorder (BD-I) is affected by symptoms of anxiety.

Patients and Methods

Eighty-seven euthymic BD-I patients were included. Patients with comorbidities other than Generalized Anxiety Disorder (GAD) or Panic Disorder (PD) were excluded. State anxiety was measured with the Brief Inventory of Anxious Responses and Situations (ISRA-B). Subjective cognitive performance was evaluated with the COBRA scale, attention with the Digit-Span Forward task and inhibition of cognitive interference was assessed with the StroopTest interference score. Multiple linear regression models were used to test if anxious symptoms were associated with attention or inhibition of cognitive interference, considering other known contributors for cognitive impairment.

Results

Attention was unaffected by anxiety symptoms, but the overall regression for inhibition of cognitive interference was significant: years of schooling (β=1.12, p = 0.001), cognitive complaints (β=0.44, p = 0.008), and anxiety (β=-0.21, p = 0.017) explained 15% of the interference score of the Stroop test (R2 = 0.15).

Conclusion

Beyond residual affective symptoms, anxious symptoms seem to affect inhibition of cognitive interference. We recommend routine testing of anxiety when considering cognitive evaluations, especially when screening for cognitive deficits.

A systematic review of the biomarkers associated with cognition and mood state in bipolar disorder

BACKGROUND

Bipolar disorder (BD) is a severe psychiatric disorder characterized by changes in mood that alternate between (hypo) mania or depression and mixed states, often associated with functional impairment and cognitive dysfunction. But little is known about biomarkers that contribute to the development and sustainment of cognitive deficits. The aim of this study was to review the association between neurocognition and biomarkers across different mood states.

METHOD

Search databases were Web of Science, Scopus and PubMed. A systematic review was carried out following the PRISMA guidelines. Risk of bias was assessed with the Newcastle-Ottawa Scale. Studies were selected that focused on the correlation between neuroimaging, physiological, genetic or peripheral biomarkers and cognition in at least two phases of BD: depression, (hypo)mania, euthymia or mixed. PROSPERO Registration No.: CRD42023410782.

RESULTS

A total of 1824 references were screened, identifying 1023 published articles, of which 336 were considered eligible. Only 16 provided information on the association between biomarkers and cognition in the different affective states of BD. The included studies found: (i) Differences in levels of total cholesterol and C reactive protein depending on mood state; (ii) There is no association found between cognition and peripheral biomarkers; (iii) Neuroimaging biomarkers highlighted hypoactivation of frontal areas as distinctive of acute state of BD; (iv) A deactivation failure has been reported in the ventromedial prefrontal cortex (vmPFC), potentially serving as a trait marker of BD.

CONCLUSION

Only a few recent articles have investigated biomarker-cognition associations in BD mood phases. Our findings underline that there appear to be central regions involved in BD that are observed in all mood states. However, there appear to be underlying mechanisms of cognitive dysfunction that may vary across different mood states in BD. This review highlights the importance of standardizing the data and the assessment of cognition, as well as the need for biomarkers to help prevent acute symptomatic phases of the disease, and the associated functional and cognitive impairment.

Long-term course of cognitive functioning in bipolar disorder: A ten-year follow-up study

INTRODUCTION

Cognitive impairments are common in bipolar disorder (BD), but the long-term course remains understudied. Longitudinal data on cognitive functioning from the start of the first treatment could help clarify pathophysiological processes that shape the illness outcome. We here aim to investigate the 10-year cognitive course in BD compared to healthy controls (HC) and the effects of clinical symptoms on cognitive trajectories.

METHODS

Fifty-six BD participants recruited within their first year of treatment and 108 HC completed clinical and cognitive assessments at baseline and 10-year follow-up. We derived eight cognitive domain scores and a cognitive composite score, which were further investigated using linear mixed model analyses. Correlation analyses were used to assess associations between the composite score and depressive, manic and psychotic symptoms.

RESULTS

BD participants performed poorer than HCs in all domains except mental speed and verbal fluency. Verbal learning and memory, verbal fluency and the composite score improved over time in both BD participants and HC, while short-term memory, mental speed, psychomotor speed and working memory were stable. We found no significant correlations between cognition and symptom level at either time point in BD participants.

CONCLUSIONS

We found evidence of long-term cognitive stability or improvement in BD participants from first treatment to 10-year follow-up. Though the BD group was impaired in all domains except mental speed and verbal fluency, the change in cognitive functioning was parallel to that of HCs. These findings are not consistent with the notion of neuroprogression in BD.

Is brain perfusion correlated to switching mood states and cognitive impairment in bipolar disorder type I? A longitudinal study using perfusion imaging approach

Type I Bipolar disorder (BD-I) is a neuropsychiatric disorder characterized by manic or mixed-featured episodes, impaired cognitive functioning, and persistent work and social functioning impairment. This study aimed to investigate within-subject; (i) differences in brain perfusion using Single-photon emission computed tomography (SPECT) between manic and euthymic states in BD-I patients; (ii) explore potential associations between altered brain perfusion and cognitive status; and (iii) examine the relationship between cerebral perfusion and mania symptom ratings. Seventeen adult patients diagnosed with BD-I in a manic episode were recruited, and clinical assessments, cognitive tests, and brain perfusion studies were conducted at baseline (mania state) and a follow-up visit 6 months later. The results showed cognitive impairment during the manic episode, which persisted during the euthymic state at follow-up. However, no significant changes in brain perfusion were observed between the manic and euthymic states. During mania, trends toward decreased perfusion in the left cerebellum and right superior parietal lobule were noted. Additionally, trends indicated a higher perfusion imbalance in the left superior and middle frontal gyrus during mania and the right superior and middle frontal gyrus during euthymia. No significant correlations existed between brain perfusion, mania symptom ratings, and cognitive performance, indicating that symptomatology might represent more than neural hemodynamics. These findings suggest that cognitive impairment may persist in BD-I patients and highlight the need for therapeutic interventions targeting cognitive deficits. More extensive studies with extended follow-up periods are warranted further to investigate brain perfusion and cognitive functioning in BD-I patients.

Course of intellectual functioning in schizophrenia and bipolar disorder: a 10-year follow-up study

BACKGROUND

Intellectual functioning (IQ) is lower in schizophrenia patients compared to healthy controls, with bipolar patients intermediate between the two. Declines in IQ mark the onset of schizophrenia, while stability is generally found post-onset. There are to date few studies on long-term IQ development in bipolar disorder. This study presents 10-year follow-up data on IQ, including premorbid IQ estimates, to track the developmental course from pre-onset levels to long-term outcomes in both patient groups compared to healthy controls.

METHODS

We included 139 participants with schizophrenia, 76 with bipolar disorder and 125 healthy controls. Mixed model analyses were used to estimate developmental slopes for IQ scores from estimated premorbid level (NART IQ) through baseline (WASI IQ) measured within 12 months post-onset, to 10-year follow-up (WASI IQ), with pairwise group comparisons. The best fit was found using a model with a breakpoint at baseline assessment.

RESULTS

Only the schizophrenia group had significant declines from estimated premorbid to baseline IQ levels compared to controls. When comparing patient groups, schizophrenia patients had steeper declines than the bipolar group. Increases in IQ were found in all groups over the follow-up period.

CONCLUSIONS

Trajectories of IQ from premorbid level to 10-year follow-up indicated declines from estimated premorbid level to illness onset in both patient groups, followed by increases during the follow-up period. Schizophrenia patients had a steeper decline than bipolar patients. During follow-up, increases indicate developmental improvement for both patient groups, but with a maintained lag compared to healthy controls due to lower premorbid levels.

Association of premorbid intelligence with level of functioning and illness severity in bipolar disorder

BACKGROUND

Bipolar disorder is a severe psychiatric syndrome defined by periodic mood shifts. Patients with bipolar disorder show cognitive impairments relative to healthy controls. The risk of developing schizophrenia, and partially also bipolar disorder, has previously been shown to increase with lower premorbid intelligence. It is not known if premorbid intelligence is associated with level of functioning and illness severity of people having developed bipolar disorder.

METHODS

We used multiple linear and ordinal regression to analyze how premorbid intelligence, as measured at conscription, associate with functional outcome and illness severity in Swedish male bipolar disorder patients (n = 788).

RESULTS

We found that lower premorbid intelligence is associated with lower percentage of time in work, after adjusting for age and bipolar subtype, and correcting for multiple comparisons. We also found a strong negative association with the total number of inpatient episodes and psychiatric comorbidity, but not with interepisodic remission, treatment with psychotherapy or lithium or the presence of any complicating socioeconomical factors. Adjusting for confounding genetic factors using polygenic risk scores for bipolar disorder and schizophrenia had no effect on the associations.

LIMITATIONS

This study lacks females and controls and may thus have lower generalizability.

CONCLUSION

In conclusion, premorbid intelligence is associated with both level of functioning and illness severity as well as comorbidity in bipolar disorder patients. Further research is needed to develop targeted interventions for this subgroup of bipolar disorder patients.

A one-year view on the association of metabolic syndrome and cognitive function in bipolar disorder - Preliminary data

BACKGROUND

Individuals with bipolar disorder have a high prevalence of metabolic syndrome and an increased risk for cognitive deficits. The aim of this longitudinal study was to investigate the trajectory of cognitive decline in dependence of metabolic syndrome over a one-year interval.

METHODS

52 well-diagnosed individuals with bipolar disorder, euthymic at baseline and follow-up (n = 17 with metabolic syndrome vs. n = 35 without metabolic syndrome) were investigated with a comprehensive neurocognitive test battery (Trail Making Test A/B, Digit Symbol Test, California Verbal Leaning Test, or the Verbal Learning and Memory Test respectively) twice within the interval of one year.

RESULTS

Patients with bipolar disorder and additional metabolic syndrome performed significantly worse in the domain of psychomotor and processing speed/attention than patients without metabolic syndrome at test point one. No deteriorating effects of metabolic syndrome on the cognitive domain scores and overall cognitive performance were found at the one-year follow up. However, no cognitive decline could be reported in both groups.

LIMITATIONS

Time interval, small sample size and selection of metabolic syndrome affected patients were the major limitations of this study.

CONCLUSION

There was no association of metabolic syndrome on the one-year trajectory of cognitive function in bipolar disorder. Future studies should expand the observation period and investigate larger samples.

Reduced theta-band neural oscillatory activity during affective cognitive control in bipolar I disorder

Individuals with bipolar I disorder (BD) have difficulty inhibiting context-inappropriate responses. However, neural mechanisms of impaired cognitive control over impulsive behaviors, especially in response to emotion, are unclear. Theta-band neural oscillatory activity over midfrontal areas is thought to reflect cognitive control. The current study examined behavioral performance and theta-band activity during inhibition to affective stimuli in BD, relative to healthy control participants (HC). Sixty-seven participants with BD and 48 HC completed a Go/No-Go task with emotional face stimuli during electroencephalography (EEG) recording. Behavior was measured with reaction time, discriminability (d') and response bias (β). Time-frequency decomposition of EEG data was used to extract event-related theta-band (4-7 Hz) neural oscillatory power and inter-trial phase consistency (ITPC) over midline fronto-central areas. Behavior and theta-band activity were compared between groups, while covarying for age. Participants with BD exhibited slower response execution times on correct Go trials and reduced behavioral discrimination of emotional versus neutral faces, compared to HC. Theta-band power and ITPC were reduced in BD relative to HC. Theta-band power was higher on No-Go trials than Go trials. The magnitude of differences in theta-band activity between Go/No-Go trial types did not differ between groups. Increased theta-band power was associated with faster response execution times, greater discrimination of differing facial expressions, and stronger tendency to respond both across the full sample and within the BD group. Attenuated midline fronto-central theta-band activity may contribute to reduced cognitive control and maladaptive behavioral responding to emotional cues in individuals with BD.

The relationship between cognition and functioning in Bipolar Disorder: An investigation using functional imaging during working memory performance

The psychosocial functioning of individuals suffering from bipolar disorder (BD) has a significant impact on prognosis and quality of life. The aim of this study was to assess brain functional correlates of psychosocial functioning in BD individuals during the performance of a working memory task. Sixty-two subjects (31 euthymic BD individuals and 31 matched healthy controls) underwent structural and functional magnetic resonance imaging scanning while performing the 1- and 2-back versions of the n-back task (1-back and 2-back). The Functional Assessment Short Test (FAST) and its subdomains were used to assess functioning. Whole brain analysis revealed only overall activation differences between BD patients and healthy controls, but the patients showed failure of de-activation in the medial frontal cortex. Six clusters of significant inverse correlation with the FAST scores were found in the dorsolateral prefrontal cortex, the superior parietal cortex, and temporo-occipital regions bilaterally, and in the left inferior frontal cortex. Cognitive and occupational functioning were the subdomains most significantly associated with brain activation in these clusters. The results suggest that poor psychosocial functioning in BD individuals is associated with hypoactivation in a range of cortical regions, including the fronto-parietal working memory network and inferior temporo-occipital regions.

MICEmi: A method to identify cognitive endophenotypes of mental illnesses

BACKGROUND

Characterizing neurocognitive endophenotypes of mental illnesses (MIs) could be useful for identifying at-risk individuals, increasing early diagnosis, improving disease subtyping, and proposing therapeutic strategies to reduce the negative effects of the symptoms, in addition to serving as a scientific basis to unravel the physiopathology of the disease. However, a standardized algorithm to determine cognitive endophenotypes has not yet been developed. The main objective of this study was to present a method for the identification of endophenotypes in MI research.

METHODS

For this purpose, a 14-expert working group used a scoping review methodology and designed a method that includes a scoring template with five criteria and indicators, a strategy for their verification, and a decision tree.

CONCLUSIONS

This work is ongoing since it is necessary to obtain external validation of the applicability of the method in future research.

Comparing the efficacy of aripiprazole as an add-on to valproate with other second-generation antipsychotics in acute mania symptoms in manic patients in Iran

BACKGROUND

Given the great importance of treating patients with bipolar disorder, the aim of this study was to compare the efficacy of aripiprazole with other second-generation antipsychotics in relieving acute symptoms of mania.

MATERIALS AND METHODS

In this study, 50 patients with bipolar I disorder, manic episode, were divided into two groups receiving aripiprazole (n = 25) and other second-generation antipsychotics (risperidone, olanzapine, and quetiapine) (n = 25) for 6 weeks. The disease severity was evaluated and compared according to YMRS and CGI criteria.

RESULTS

The mean severity of mania according to YMRS and CGI, at week 0 in comparison with weeks 2, 4 and 6 in both groups was significantly different (p < 0.0001) and the treatment with Aripiprazole at week 2 (p < 0.0001) and 4 (p = 0.0002) was significantly better than the other second-generation antipsychotics. The two groups also showed an overall improvement in CGI-based results at weeks 4 and 6 (p = 0.002). In addition, the efficacy index for aripiprazole at weeks 4 (p = 0.011) and 6 (p < 0.0001) as well as disease improvement in the second (p < 0.0001) and fourth (p = 0.026) weeks after treatment were better than the other second-generation antipsychotics.

CONCLUSIONS

Aripiprazole and other second-generation antipsychotics, 2 weeks after initiation of treatment, significantly reduced mania severity in patients with bipolar disorder, however, aripiprazole seems to be more efficient and faster for controlling mania in patients with bipolar disorder.KEY POINTSAripiprazole and other second-generation antipsychotics, 2 weeks after initiation of treatment, significantly reduced mania severity in patients with bipolar disorder.Comparison between the two drugs, aripiprazole showed a more beneficial role in the second and fourth weeks than second-generation antipsychotics.Due to the fact that the possible mechanisms involved in the role of aripiprazole have not been considered compared to other antipsychotics in patients with bipolar disorder, there is a need for more extensive studies in this field.

Event-related potential correlates of affective response inhibition in bipolar I disorder: Comparison with schizophrenia

BACKGROUND

Individuals with bipolar I disorder (BD) have difficulty inhibiting context-inappropriate responses. The neural mechanisms contributing to these difficulties, especially in emotional contexts, are little understood. This study aimed to inform mechanisms of impaired impulsivity control in response to emotion in BD, and whether response inhibition indices are altered to a similar degree in schizophrenia spectrum disorders (SZ). We examined alterations to behavioral performance and event-related potentials (ERPs) during inhibition to affective stimuli in BD, relative to healthy control participants (HC) and SZ.

METHODS

Sixty-six participants with BD, 32 participants with SZ, and 48 HC completed a Go/No-Go task with emotional face stimuli while electroencephalography was recorded. Behavioral signal detection metrics (perceptual sensitivity, response bias) and ERPs (N200, P300) were compared across groups.

RESULTS

Relative to HC, participants with BD showed reduced (1) discrimination of Go vs. No-Go stimuli (i.e., emotional vs. neutral faces), and (2) P300 amplitudes elicited by emotional faces. Results similarly extended to SZ: BD and SZ groups did not differ on behavioral performance nor ERP amplitudes.

LIMITATIONS

Aspects of the Go/No-Go task design may have limited findings, and medication effects on ERP amplitudes in patient samples cannot be fully ruled out.

CONCLUSIONS

Findings suggest the difficulty participants with BD and SZ experienced on the current affective response inhibition task lied largely in discriminating between facial expressions. Difficulties with discriminating emotional from neutral expressions may contribute to difficulties with appropriate behavioral responding in social-affective contexts for individuals with BD and SZ.

Neuropsychological aspects of bipolar disorder

Bipolar disorder (BD) is a chronic condition with serious consequences on the health and functionality of patients who suffer from it, with a high heritability and segregation, and aprevalence of between 1% and 2%. Neuropsychological deficits have been implicated as a very important issue related to BD prognosis, so a review was conducted of these deficits, the related factors and their functional consequences. It has been determined that the presence of neuropsychological deficits can vary in patients with BD according to their mood state, with a great influence of depressive symptoms on the cognitive variability of patients with respect to the general population and differences with respect to patients in the manic phase. In euthymic patients, the most affected cognitive domains are those of memory, attention, and executive function, associated with a more severe disease, sociodemographic vulnerability factors, and stable over time. A relationship has been found between poor cognitive performance, especially executive dysfunction, and objective functional deficit. Furthermore, cognitive differences have been outlined between BD and other serious mental illnesses that are described in this review.

Clinical Value of Inflammatory and Neurotrophic Biomarkers in Bipolar Disorder: A Systematic Review and Meta-Analysis

Bipolar disorder (BD) is a multifactorial chronic psychiatric disease highly defined by genetic, clinical, environmental and social risk factors. The present systematic review and meta-analysis aimed to examine the relationship between inflammatory and neurotrophic factors and clinical, social and environmental factors involved in the development and the characterization of BD. Web of Science, PubMed, PsycINFO, Scopus and Science Direct were searched by two independent reviewers. The systematic review was registered in PROSPERO (CRD42020180626). A total of 51 studies with 4547 patients with a diagnosis of BD were selected for systematic review. Among them, 18 articles were included for meta-analysis. The study found some evidence of associations between BDNF and/or inflammatory factors and different stressors and functional and cognitive impairment, but limitations prevented firm conclusions. The main finding of the meta-analysis was a negative correlation between circulating levels of BDNF and depression severity score (standardized mean difference = −0.22, Confidence Interval 95% = −0.38, −0.05, p = 0.01). Evidence indicates that BDNF has a role in the depressive component of BD. However, the poor consistency found for other inflammatory mediators clearly indicates that highly controlled studies are needed to identity precise biomarkers of this disorder.

The relations between executive functions and occupational functioning in individuals with bipolar disorder: a scoping review

Background

Patients with bipolar disorder experience impairments in their occupational functioning, despite remission of symptoms. Previous research has shown that neurocognitive deficits, especially deficits in executive functions, may persist during euthymia and are associated with diminished occupational functioning.

Objectives

The aim of this scoping review was to identify published studies that report on the relationships between executive functions and occupational functioning in BD to review current knowledge and identify knowledge gaps. In addition to traditional neuropsychological approaches, we aimed to describe executive functioning from a self-regulation perspective, including emotion regulation.

Methods

We applied the methodological framework as described by Arksey and O’Malley (Int J Soc Res Methodol Theory Pract 8:19–32, 2005) and Levac et al. (Implement Sci 5:1–9, 2010). We searched PubMed and psycINFO for literature up to November 2021, after which we screened papers based on inclusion criteria. Two reviewers independently performed the screening process, data charting process, and synthesis of results.

Results

The search yielded 1202 references after deduplication, of which 222 remained after initial screening. The screening and inclusion process yielded 82 eligible papers in which relationships between executive functions and occupational functioning are examined.

Conclusion

Neurocognitive deficits, including in executive functions and self-regulation, are associated with and predictive of diminished occupational functioning. Definitions and measurements for neurocognitive functions and occupational functioning differ greatly between studies, which complicates comparisons. Studies on functional remediation show promising results for improving occupational functioning in patients with BD. In research and clinical practice more attention is needed towards the quality of work functioning and the various contexts in which patients with BD experience deficits.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40345-022-00255-7.

BIPOLAR DISORDER, MOOD STABILIZERS AND COGNITIVE FLEXIBILITY: TRANSLATIONALLY DISSECTING ILLNESS FROM DRUG EFFECTS

Bipolar disorder (BD) effects on cognition are confounded by the putative cognitive impact of its major pharmacological treatments, given the neurotrophic potential of mood stabilizers, particularly lithium. We examined the area of cognitive flexibility (CF), aiming to disentangle BD from medication effects, using translational methodology. CF was assessed by CANTAB-IED (intra- extra-dimensional shift; Study 1, euthymic BD participants) and its animal analogue (Study 2, rats). Both studies included groups (1) control, (2) lithium, chronic, current treatment (LI-CHRON-C, A: >2 years, N=32; B: 2 months, N=11); (3) valproate, chronic, current treatment (VPA-CHRON-C, A: >2 years, N=30; B: 2 months, N=12). Study 2 included 2 additional groups; Group 4: LI-CHRON-PAST (2 months, stopped 1 month pretest, N=13); Group 5: LI-ACUTE (LI on test days only, N=13). In Study 1, neither total nor stage (discrimination: D; reversal R; intra- extra-dimensional shifts: IED) IED errors differed between groups [(Kruskal-Wallis: H(2, N= 94) 0.95 > p > 0.65]. Similarly in Study 2, errors did not differentiate the 5 pharmacological groups. Differences emerged only between LI-ACUTE and Controls in response latencies (D, R, IED ANOVAS: 0.002 > p > 0.0003; contrasts D, R: p = 0.002, 0.0001). In conclusion, LI and VPA BD patients were indistinguishable from Controls in IED errors, as were animals treated with LI-CHRON, current or past, or VPA-CHRON-C vs Controls. LI-ACUTE treatment produced significant latency deficits vs. Controls. Within the limitations of translational comparisons, our results suggest that the normal CF noted in euthymic BDs is not attributable to mood stabilizer effects.

Long-term outcome predictors after functional remediation in patients with bipolar disorder

BACKGROUND

Improving functioning in patients with bipolar disorder (BD) is one of the main objectives in clinical practice. Of the few psychosocial interventions that have been specifically developed to enhance the psychosocial outcome in BD, functional remediation (FR) is one which has demonstrated efficacy. The aim of this study was to examine which variables could predict improved functional outcome following the FR intervention in a sample of euthymic or subsyndromal patients with BD.

METHODS

A total of 92 euthymic outpatients were included in this longitudinal study, with 62 completers. Partial correlations controlling for the functional outcome at baseline were calculated between demographic, clinical and neurocognitive variables, and functional outcome at endpoint was assessed by means of the Functioning Assessment Short Test scale. Next, a multiple regression analysis was run in order to identify potential predictors of functional outcome at 2-year follow-up, using the variables found to be statistically significant in the correlation analysis and other variables related to functioning as identified in the previous scientific literature.

RESULTS

The regression model revealed that only two independent variables significantly contributed to the model (F(6,53): 4.003; p = 0.002), namely verbal memory and inhibitory control. The model accounted for 31.2% of the variance. No other demographic or clinical variable contributed to the model.

CONCLUSIONS

Results suggest that patients with better cognitive performance at baseline, especially in terms of verbal memory and executive functions, may present better functional outcomes at long term follow-up after receiving functional remediation.

The long-term course of cognition in bipolar disorder: a systematic review and meta-analysis of patient-control differences in test-score changes

Neuropsychological impairment represents a key aspect of bipolar disorder (BD) that is evident even in early-course patients and is a strong predictor of functional outcomes among those affected. Previous meta-analyses of longitudinal studies suggest that BD-related cognitive deficits may not progress along the course of the disorder. However, short test-retest periods were used in most primary studies and comparisons with healthy controls were limited. The aim of this review was to synthesize the findings of research reports comparing long-term neurocognitive trajectories between BD patients and healthy individuals. PubMed, PsycINFO, and Scopus databases were searched from inception through July 2021. Publications were considered for inclusion if they reported cognitive test scores of BD patients and healthy controls at two different time points, with a minimum test-retest interval of 5 years. Fifteen studies compared the long-term course of cognition in BD patients with that of healthy controls. Ten of these were included in the quantitative analysis and involved 540 BD patients and 644 healthy individuals (mean follow-up period: 8.9 years). Patient-control effect sizes (standardized mean differences) were calculated for test-score changes in 24 neuropsychological variables and combined by means of meta-analytic procedures. No significant differences were found between patients and controls regarding long-term cognitive outcomes. These findings are consistent with previous shorter-term longitudinal meta-analyses and do not provide evidence for progressive cognitive deterioration in most bipolar individuals. Future studies should address the longitudinal course of cognition in different subgroups of BD patients and its prognostic and therapeutic value.

Sleep quality and neuropsychological functioning in bipolar I disorder

BACKGROUND

Individuals with bipolar I disorder (BD-I) experience both poor sleep and neuropsychological dysfunction relative to non-psychiatric populations, which limits functional recovery. Poor sleep adversely affects learning, memory, and executive functioning in healthy individuals; however, little is known about the role of poor sleep in neuropsychological functioning in BD-I. We tested whether sleep disturbance was greater in BD-I than healthy control participants (HC), and compared the effect of sleep quality on learning, memory, and executive functioning between BD-I and HC.

METHODS

Participants with BD-I (N=250) and HC (N=206) completed the Pittsburgh Sleep Quality Index, neuropsychological testing, and clinician-administered mood measures as part of a naturalistic study of bipolar disorder. We examined effects of both diagnosis and sleep quality on neuropsychological functioning.

RESULTS

Relative to HC, BD-I showed poorer sleep quality and neuropsychological functioning in verbal learning, verbal and visual memory, processing speed, psychomotor speed, inhibitory control, and selective attention (7/9 domains). Poor sleep quality was associated with poorer verbal learning, verbal fluency, processing speed, and interference control (4/9). Effects of poor sleep on neuropsychological functioning did not differ between BD-I and HC.

LIMITATIONS

The assessment of sleep quality using a self-report measure and the effects of medications/sleeping aids (given the naturalistic study design) should be considered when interpreting results.

CONCLUSIONS

Those with BD-I experiencing poor sleep may also be more vulnerable to verbal learning and executive functioning impairments. The findings of poor sleep in relation to poorer neuropsychological functioning have implications for assessment and treatment of sleep disturbance in BD-I.

Is processing speed a valid neurocognitive endophenotype in bipolar disorder? Evidence from a longitudinal, family study

BACKGROUND

Substantial evidence supports the existence of neurocognitive endophenotypes in bipolar disorder (BD), but very few longitudinal studies have included unaffected relatives. In a 5-year, follow-up, family study, we have recently suggested that deficits in manual motor speed and visual memory could be endophenotype candidates for BD. We aimed to explore whether this also applies to processing speed.

METHODS

A sample of 348 individuals, including 163 BD patients, 65 unaffected first-degree relatives (BD-Rel) and 120 genetically unrelated healthy controls (HC), was assessed with the Digit Symbol Substitution Test (DSST) on two occasions over a 2-year period (T1, T2). DSST values were controlled for age, years of education, occupational status, and subsyndromic mood symptoms. Differences between groups were evaluated with ANCOVAs.

RESULTS

At T1 BD performed significantly worse than HC (p < 0.001; Cohen's d = 1.38) and BD-Rel (p < 0.001; Cohen's d = 0.82). BD-Rel showed an intermediate performance with significant differences with HC (p < 0.01; Cohen's d = 0.50). Similarly, at T2 BD performed significantly worse than HC (p < 0.001; Cohen's d = 1.44) and BD-Rel (p < 0.01; Cohen's d = 0.51). BD-Rel performance was intermediate and significantly lower than that of HC (p < 0.01; Cohen's d = 0.97). A Repeated Measures ANOVA revealed no significant between-group differences in performance over time (p > 0.05).

CONCLUSIONS

The results of this longitudinal, family study suggest that impaired processing speed may represent a suitable cognitive endophenotype for BD. Further research on the field is required to confirm these preliminary findings.

Manic morbidity and executive function impairment as determinants of long-term psychosocial dysfunction in bipolar disorder

OBJECTIVE

In this study, we aimed to evaluate the role of cognitive performance and measures of clinical course-including both syndromal and subsyndromal symptomatology-as determinants of the functional outcome of patients with Bipolar Disorder (BD) during a mean follow-up period of more than 4 years.

METHODS

Seventy patients with euthymic BD completed a neurocognitive battery at study entry. Clinical course was assessed prospectively for a period longer than 48 months by two measures: time spent ill (documented using a modified life charting technique) and density of affective episodes (defined as the number of depressive and hypo/manic episodes per year of follow-up). Psychosocial functioning was assessed during euthymia using the Functioning Assessment Short Test (FAST) total score at the end of follow-up period.

RESULTS

Baseline deficits in phonological fluency, a measure of executive functions (β = -2.49; 95% CI = -3.98, -0.99), and density of hypo/manic episodes during follow-up (β = 6.54; 95% CI = 0.43, 12.65) were independently associated with FAST total score at the end of study.

CONCLUSIONS

Although interrelated, manic morbidity and executive function impairments independently contribute to long-term psychosocial dysfunction in BD and could be potential targets of intervention.

Long-term trajectory of cognitive performance in people with bipolar disorder and controls: 6-year longitudinal study

BACKGROUND

Cross-sectional studies have found impaired cognitive functioning in patients with bipolar disorder, but long-term longitudinal studies are scarce.

AIMS

The aims of this study were to examine the 6-year longitudinal course of cognitive functioning in patients with bipolar disorder and healthy controls. Subsets of patients were examined to investigate possible differences in cognitive trajectories.

METHOD

Patients with bipolar I disorder (n = 44) or bipolar II disorder (n = 28) and healthy controls (n = 59) were tested with a comprehensive cognitive test battery at baseline and retested after 6 years. We conducted repeated measures ANCOVAs with group as a between-subject factor and tested the significance of group and time interaction.

RESULTS

By and large, the change in cognitive functioning between baseline and follow-up did not differ significantly between participants with bipolar disorder and healthy controls. Comparing subsets of patients, for example those with bipolar I and II disorder and those with and without manic episodes during follow-up, did not reveal subgroups more vulnerable to cognitive decline.

CONCLUSIONS

Cognitive performance remained stable in patients with bipolar disorder over a 6-year period and evolved similarly to healthy controls. These findings argue against the notion of a general progressive decline in cognitive functioning in bipolar disorder.

Pediatric bipolar disorder: Executive, linguistic, mnemonic, and cognitive efficiency mapping

Neuropsychological assessment can enrich our understanding of Pediatric Bipolar Disorder (PB). This study aimed to: (1) analyze the occurrence of neuropsychological frequency of deficits and difficulties in children with PB; (2) verify whether there is a performance difference between PB type I (PB-I) and PB type II (PB-II)/unspecified, and between PB with and without ADHD; and (3) verify the cognitive efficiency differences within the PB group and control groups, and among clinical subgroups. Participants in the study were 16 children diagnosed with PB and 40 children with typical development (6-12 years old). The results indicated a high frequency of deficits/difficulties in verbal fluency, cognitive efficiency in performing basic abilities, inhibitory control, cognitive flexibility, and working memory, with emphasis on verbal and executive losses. There were indications that type PB-I and comorbidity with ADHD negatively impact a child's neuropsychological development. The clinical group showed more cognitive efficiency losses compared with the control group, and greater losses were observed in PB-I and in PB with ADHD. The role of neuropsychological evaluation in multidomain and nonlinear statistical analysis is critical to gaining an understanding of the clinical and cognitive heterogeneity of PB.

Neuropsychological Aspects of Bipolar Disorder

Bipolar disorder (BD) is a chronic condition with serious consequences on the health and functionality of patients who suffer from it, with a high heritability and segregation, and a prevalence of between 1% and 2%. Neuropsychological deficits have been implicated as a very important issue related to BD prognosis, so a review was conducted of these deficits, the related factors and their functional consequences. It has been determined that the presence of neuropsychological deficits can vary in patients with BD according to their mood state, with a great influence of depressive symptoms on the cognitive variability of patients with respect to the general population and differences with respect to patients in the manic phase. In euthymic patients, the most affected cognitive domains are those of memory, attention, and executive function, associated with a more severe disease, sociodemographic vulnerability factors, and stable over time. A relationship has been found between poor cognitive performance, especially executive dysfunction, and objective functional deficit. Furthermore, cognitive differences have been outlined between BD and other serious mental illnesses that are described in the review.

The impact of the trajectory of bipolar disorder on global cognitive function: A one-year clinical prospective case-control study

BACKGROUND

The relationship between cognitive function and relapse of affective episodes in bipolar disorder (BD) is rarely studied. The aim of this prospective, longitudinal, case-control study was to assess the trajectory of cognitive function and mood occilations within a one-year period in patients with BD relative to healthy control (HC) individuals.

METHODS

The sample included 86 outpatients with BD in euthymia, and 44 gender-and-age-matched HC. All participants were evaluated with clinical assessement and neuropsychological testing at baseline and during euthymia after a year. Further patients with BD were reevaluated if they developed a new affective episode during follow-up. The patients´ affective states were recorded on a weekly basis as asymptomatic, subthreshold level, major depression or (hypo)mania. Cognitive changes over time were measured for a global cognitive score and for the four cognitive domains: 'working memory and executive skills', 'psychomotor speed', 'sustained attention', and 'verbal learning and memory' in patients and HC.

RESULTS

The study showed that cognitive performance in patients with BD was unaltered compared to baseline when they stabilised in euthymia following an affective episode and, at the one-year follow-up. Cognitive performance showed practice effect, thus improved within a year across patients with BD and HC. Furthermore, cognitive functions were not related to clinical subtypes BDI/II, prior psychosis, the polarity of the relapse and week-to-week mood fluctuations during follow-up. Functioning correlated weakly to moderately with week-to-week mood fluctuations.

LIMITATIONS

Modest sample size.

CONCLUSION

A one-year trajectory of BD seems to have no direct negative impact on cognitive function.

Doxycycline reverses cognitive impairment, neuroinflammation and oxidative imbalance induced by D-amphetamine mania model in mice: A promising drug repurposing for bipolar disorder treatment?

Immune-inflammatory mechanisms are involved in the pathophysiology of bipolar disorder. Tetracyclines present neuroprotective actions based on their anti-inflammatory and microglia suppressant effects. Doxycycline (DOXY) is a tetracycline that demonstrates a better usage profile with protective actions against inflammation and CNS injury. Here, we investigated the effects of DOXY against behavioral, neuroinflammatory, and pro-oxidative changes induced by the d-amphetamine mania model. Adult mice were given d-amphetamine 2.0 mg/kg or saline for 14 days. Between days 8 and 14, received lithium, DOXY (25 or 50 mg/kg), or their combination (lithium+DOXY) on both doses. We collected the brain areas prefrontal cortex (PFC), hippocampus, and amygdala to evaluate inflammatory and oxidative alterations. D-amphetamine induced hyperlocomotion and impairment in recognition and working memory. Lithium reversed hyperlocomotion but could not restore cognitive alterations. DOXY alone (at both doses) or combined with lithium reversed d-amphetamine-induced cognitive changes. DOXY, better than lithium, reversed the d-amphetamine-induced rise in TNFα, MPO, and lipid peroxidation. DOXY reduced the hippocampal expression of Iba1 (a marker of microglial activation), inducible nitric oxide synthase (iNOS), and nitrite. Combined with lithium, DOXY increased the phosphorylated (inactivated) form of GSK3β (Ser9). Therefore, DOXY alone or combined with lithium reversed cognitive impairment and neuroinflammation induced by the mice's d-amphetamine model. This study points to DOXY as a promising adjunctive tool for bipolar disorder treatment focused on cognition and neuroimmune changes. Our data provide the first rationale for clinical trials investigating DOXY therapeutic actions in bipolar disorder mania.

Cumulative Cardiovascular Disease Risk and Triglycerides Differentially Relate to Subdomains of Executive Function in Bipolar Disorder; preliminary findings

OBJECTIVES

Cardiovascular disease is disproportionally prevalent in bipolar disorder (BD) and has been linked to cognition in preliminary studies. Herein we evaluate the association between known risk factors for cardiovascular disease and executive function in BD patients compared to healthy controls.

METHODS

In a sample of n=57 individuals (n=23 BD, n=34 controls) we assessed two subdomains of executive function; cognitive flexibility (using the Trail Making Test - Part B) and cognitive inhibition (using the Stroop Colour Word Interference Task). Cardiovascular risk was assessed by means of serum triglyceride levels, body mass index (BMI) and waist circumference, as well as dietary saturated fat intake and a sex-specific cumulative cardiovascular risk score calculated using the Framingham Heart Study method.

RESULTS

Patients with BD had higher BMI and waist circumference, with more BD patients categorized as having central obesity than controls. In the BD group only, higher triglyceride levels were associated with worse cognitive flexibility, and elevated cumulative cardiovascular disease risk was associated with worse cognitive inhibition. No correlations between cardiovascular risk factors and executive function were evident in the control group.

LIMITATIONS

The study was limited by the small sample size and should be considered hypothesis-generating CONCLUSIONS: The associations between triglyceride levels, cumulative cardiovascular disease risk and executive functioning evident in BD in this study preliminarily indicate the potential for mechanistic overlap of physical health and cognitive function in the disorder.

The impact of a new affective episode on psychosocial functioning, quality of life and perceived stress in newly diagnosed patients with bipolar disorder: A prospective one-year case-control study

BACKGROUND

Bipolar disorder (BD) has been associated with impaired functioning during periods of euthymia. This prospective one-year case-control study investigated the impact of a new affective episode on psychosocial functioning, quality of life (QoL) and perceived stress in newly diagnosed patients with BD in euthymia.

METHODS

Clinically evaluated psychosocial functioning (Functioning Assessment Short Test, FAST), self-reported QoL (WHOQoL-BREF scale) and stress (Cohens' Perceived Stress Scale) were collected from 87 patients with BD with (BD-E) (n=38) and without (BD-NE) (n=44) clinical relapse and 44 age and gender matched healthy control (HC) individuals at baseline (T0), following an episode if it occurred (T2) and at one-year follow-up (T3).

RESULTS

Patients with BD presented with poorer functioning compared to HC individuals at T0 and T3. There was no statistically significantly difference in the changes in FAST (-1.2, adjusted-p=0.82), PSS (0.34, adjusted-p=0.93) or WHOQoL (-0.67, adjusted-p=0.93) between BD-E and BD-NE during the one-year follow-up. The subgroup BD-E had statistically significantly higher FAST and stress scores and lower WHOQoL-scores compared to BD-NE at both T0 and T3.

LIMITATIONS

Modest sample size.

CONCLUSION

Functioning is impaired in newly diagnosed patients with BD in a euthymic state, however, a new affective episode does not affect functioning during subsequent euthymia at one-year follow-up. Patients with BD-E presented with overall most impaired functioning, highlighting the importance of early intervention strategies as essential to identify and treat patients at high risk of relapse and poor outcome.

Predictors of High Psychosocial Functioning in Bipolar Disorder

The aim of this study was to identify predictors of high psychosocial functioning in patients with bipolar disorder (BD). One hundred forty-five outpatients with BD and 50 healthy controls were included. Patients were categorized as having high psychosocial functioning if they concomitantly met three conditions: a) General Assessment of Functioning greater than 90, b) full-time employment, and c) full functional recovery. Clinical, demographical, and neurocognitive variables were assessed and considered as potential predictors of high functioning in regression models. We found that 22.8% (n = 33) of patients exhibited high psychosocial functioning. BD type II, higher educational level, and better performance in verbal memory, attention, and executive functions were independent predictors of high psychosocial functioning. Our results provide evidence that functional outcomes are heterogeneous in BD, including a percentage of patients who maintain good to excellent psychosocial functioning despite their illness. Neurocognitive functioning could be one of the most influential factors to explain this heterogeneity.

The Effect of Cognitive Impairment on the Prognosis of Major Depressive Disorder

The study recruited 168 patients diagnosed with major depressive disorder (MDD). The nine-item Patient Health Questionnaire (PHQ-9) and Perceived Deficits Questionnaire for Depression (PDQ-D) were lower and the Digit Symbol Substitution Test (DSST) was higher in the community volunteers than those in MDD patients. Depression-related scores (17-item Hamilton Depression Rating Scale [HAMD-17], Clinical Global Impressions-Severity of Illness Scale [CGI-S], and PHQ-9), functioning-related scores (Sheehan Disability Scale [SDS]), and Work Efficiency and Activity Damage-Specific Health Problems questionnaire work productivity loss were decreased, and the quality of life-related scores (European Quality of life-5 Dimensions [EQ-5D] utility score) were increased in the MDD patients. PDQ-D was decreased and DSST was increased with the increase of follow-up time. Linear regression indicated that cognitive symptoms (PDQ-D and DSST) improved more slowly than depressive symptoms (PHQ-9). At baseline, PDQ-D was related with functioning (SDS and work productivity loss). PDQ-D and DSST were related with EQ-5D utility score. In addition, at month 6, PDQ-D was related with functioning (SDS and work productivity loss) and EQ-5D utility score. Cognitive impairment might be a risk for MDD and MDD-related changes in the functioning and quality of life.

Functioning in euthymic patients with bipolar disorder: A systematic review and meta-analysis using the Functioning Assessment Short Test

OBJECTIVES

Systematically review the prevalence of functional impairment (FI) in euthymic patients with bipolar disorder (BD), as assessed only with the Functioning Assessment Short Test (FAST), explore the prevalence of this impairment among all the domains, identify the most compromised of them and the clinical variables associated with low functioning in this population.

METHODS

Meta-analyses were performed, searching for relevant papers published from 2007 to 2019 in Medline, Embase, Cochrane, PsycINFO databases and via hand-searching, without language restrictions. 1128 studies were initially identified, 13 of which were ultimately chosen based on the eligibility criteria. A two-step meta-analysis was performed using the mean difference with a 95% confidence interval for continuous variables and proportion estimation with a fixed-effects model for categorical variables.

RESULTS

In the first step, all FAST domains showed worse FI in patients than in healthy controls, with significant differences between groups. In the second step, the prevalence of FI domains were as follows: global, 58.6%; occupational, 65.6%; cognitive, 49.2%; autonomy, 42.6%; interpersonal relationships, 42.1%; leisure, 29.2%; and financial issues, 28.8%. Residual depressive symptoms were the most frequently cited variable associated with FI.

CONCLUSIONS

This study reinforces the relevant functional impact of BD in this population and suggests that the occupational domain may be the most impaired. Greater efforts should be directed toward targeting functioning in patient care, as it constitutes the most meaningful endpoint of response to treatment, especially with occupational and cognitive rehabilitation, thus allowing patients to overcome the course of illness and carry fulfilling lives.

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.

The GLP-1 receptor agonist liraglutide reverses mania-like alterations and memory deficits induced by D-amphetamine and augments lithium effects in mice: Relevance for bipolar disorder

Metabolic and psychiatric disorders present a bidirectional relationship. GLP-1 system, known for its insulinotropic effects, has also been associated with numerous regulatory effects in cognitive and emotional processing. GLP-1 receptors (GLP-1R) agonists present neuroprotective and antidepressant/anxiolytic properties. However, the effects of GLP-1R agonism in bipolar disorder (BD) mania and the related cognitive disturbances remains unknown. Here, we investigated the effects of the GLP-1R agonist liraglutide (LIRA) at monotherapy or combined with lithium (Li) against D-amphetamine (AMPH)-induced mania-like symptoms, brain oxidative and BDNF alterations in mice. Swiss mice received AMPH 2 mg/kg or saline for 14 days. Between days 8-14, they received LIRA 120 or 240 μg/kg, Li 47.5 mg/kg or the combination Li + LIRA, on both doses. After behavioral evaluation the brain areas prefrontal cortex (PFC), hippocampus and amygdala were collected. AMPH induced hyperlocomotion, risk-taking behavior and multiple cognitive deficits which resemble mania. LIRA reversed AMPH-induced hyperlocomotion, working and recognition memory impairments, while Li + LIRA240 rescued all behavioral changes induced by AMPH. LIRA reversed AMPH-induced hippocampal oxidative and neurotrophic changes. Li + LIRA240 augmented Li antioxidant effects and greatly reversed AMPH-induced BDNF changes in PFC and hippocampus. LIRA rescued the weight gain induced by Li in the course of mania model. Therefore, LIRA can reverse some mania-like behavioral alterations and combined with Li augmented the mood stabilizing and neuroprotective properties of Li. This study points to LIRA as a promising adjunctive tool for BD treatment and provides the first rationale for the design of clinical trials investigating its possible antimanic effect.

Transdiagnostic neurocognitive subgroups and functional course in young people with emerging mental disorders: a cohort study

BACKGROUND

Neurocognitive impairments robustly predict functional outcome. However, heterogeneity in neurocognition is common within diagnostic groups, and data-driven analyses reveal homogeneous neurocognitive subgroups cutting across diagnostic boundaries.

AIMS

To determine whether data-driven neurocognitive subgroups of young people with emerging mental disorders are associated with 3-year functional course.

METHOD

Model-based cluster analysis was applied to neurocognitive test scores across nine domains from 629 young people accessing mental health clinics. Cluster groups were compared on demographic, clinical and substance-use measures. Mixed-effects models explored associations between cluster-group membership and socio-occupational functioning (using the Social and Occupational Functioning Assessment Scale) over 3 years, adjusted for gender, premorbid IQ, level of education, depressive, positive, negative and manic symptoms, and diagnosis of a primary psychotic disorder.

RESULTS

Cluster analysis of neurocognitive test scores derived three subgroups described as 'normal range' (n = 243, 38.6%), 'intermediate impairment' (n = 252, 40.1%), and 'global impairment' (n = 134, 21.3%). The major mental disorder categories (depressive, anxiety, bipolar, psychotic and other) were represented in each neurocognitive subgroup. The global impairment subgroup had lower functioning for 3 years of follow-up; however, neither the global impairment (B = 0.26, 95% CI -0.67 to 1.20; P = 0.581) or intermediate impairment (B = 0.46, 95% CI -0.26 to 1.19; P = 0.211) subgroups differed from the normal range subgroup in their rate of change in functioning over time.

CONCLUSIONS

Neurocognitive impairment may follow a continuum of severity across the major syndrome-based mental disorders, with data-driven neurocognitive subgroups predictive of functional course. Of note, the global impairment subgroup had longstanding functional impairment despite continuing engagement with clinical services.

Convergent neural substrates of inattention in bipolar disorder patients and dopamine transporter-deficient mice using the 5-choice CPT

OBJECTIVES

Bipolar disorder (BD) is a debilitating psychiatric illness affecting 2%-5% of the population. Although mania is the cardinal feature of BD, inattention and related cognitive dysfunction are observed across all stages. Since cognitive dysfunction confers poor functional outcome in patients, understanding the relevant neural mechanisms remains key to developing novel-targeted therapeutics.

METHODS

The 5-choice continuous performance test (5C-CPT) is a mouse and fMRI-compatible human attentional task, requiring responding to target stimuli while inhibiting responding to nontarget stimuli, as in clinical CPTs. This task was used to delineate systems-level neural deficits in BD contributing to inattentive performance in human subjects with BD as well as mouse models with either parietal cortex (PC) lesions or reduced dopamine transporter (DAT) expression.

RESULTS

Mania BD participants exhibited severe 5C-CPT impairment. Euthymic BD patients exhibited modestly impaired 5C-CPT. High impulsivity BD subjects exhibited reduced PC activation during target and nontarget responding compared with healthy participants. In mice, bilateral PC lesions impaired both target and nontarget responding. In the DAT knockdown mouse model of BD mania, knockdown mice exhibited severely impaired 5C-CPT performance versus wildtype littermates.

CONCLUSIONS

These data support the role of the PC in inattention in BD-specifically regarding identifying the appropriate response to target vs nontarget stimuli. Moreover, the findings indicate that severely reduced DAT function/hyperdopaminergia recreates the attentional deficits observed in BD mania patients. Determining the contribution of DAT in the PC to attention may provide a future target for treatment development.

Modelling associations between neurocognition and functional course in young people with emerging mental disorders: a longitudinal cohort study

Neurocognitive impairment is commonly associated with functional disability in established depressive, bipolar and psychotic disorders. However, little is known about the longer-term functional implications of these impairments in early phase transdiagnostic cohorts. We aimed to examine associations between neurocognition and functioning at baseline and over time. We used mixed effects models to investigate associations between neurocognitive test scores and longitudinal social and occupational functioning ("Social and Occupational Functioning Assessment Scale") at 1-7 timepoints over five-years in 767 individuals accessing youth mental health services. Analyses were adjusted for age, sex, premorbid IQ, and symptom severity. Lower baseline functioning was associated with male sex (coefficient -3.78, 95% CI -5.22 to -2.34 p < 0.001), poorer verbal memory (coefficient 0.90, 95% CI 0.42 to 1.38, p < 0.001), more severe depressive (coefficient -0.28, 95% CI -0.41 to -0.15, p < 0.001), negative (coefficient -0.49, 95% CI -0.74 to -0.25, p < 0.001), and positive symptoms (coefficient -0.25, 95% CI -0.41 to -0.09, p = 0.002) and lower premorbid IQ (coefficient 0.13, 95% CI 0.07 to 0.19, p < 0.001). The rate of change in functioning over time varied among patients depending on their sex (male; coefficient 0.73, 95% CI 0.49 to 0.98, p < 0.001) and baseline level of cognitive flexibility (coefficient 0.14, 95% CI 0.06 to 0.22, p < 0.001), such that patients with the lowest scores had the least improvement in functioning. Impaired cognitive flexibility is common and may represent a meaningful and transdiagnostic target for cognitive remediation in youth mental health settings. Future studies should pilot cognitive remediation targeting cognitive flexibility while monitoring changes in functioning.

Polypharmacy-induced cognitive dysfunction and discontinuation of psychotropic medication: a neuropsychological case report

Polypharmacy is common in patients with a diagnosis of bipolar disorder. Although polypharmacy is known to increase the risk of iatrogenic neurological conditions, the recovery of cognitive function after drug withdrawal has been rarely documented in psychiatric patients using standardized neuropsychological methods. We present a neuropsychological case report of patient SN, a 41-year-old woman who developed a socially and occupationally detrimental condition of cognitive dysfunction likely induced by long-term exposure to lithium and other psychiatric medications. To shed light on SN's cognitive deficits and their recovery after drug withdrawal, neuropsychological assessments were conducted before, and approximately 2 years after, lithium and other psychiatric drugs were discontinued. Selective cognitive impairments were observed before drug discontinuation in visuomotor speed, visuoperceptual reasoning and delayed visual memory. Partial, but not complete, recovery of function was observed 2 years after drug withdrawal.

Lifetime Psychotic Symptoms, Subthreshold Depression and Cognitive Impairment as Barriers to Functional Recovery in Patients with Bipolar Disorder

(1) Background: bipolar disorder (BD) is a chronic disease that often leads to functional impairment. The objective of this study is to elucidate which variables are associated with better functional outcomes in a sample of euthymic patients with BD. (2) Methods: patients were recruited at the Hospital Clinic of Barcelona and they underwent a clinical interview, a functional assessment, and a comprehensive neuropsychological evaluation. After that, patients were divided into two groups according to the Functioning Assessment Short Test total score: functionally remitted vs. functionally impaired. Following this, a multivariate logistic regression was run in order to identify clinical, demographic and cognitive factors associated with functional remission. (3) Results: a total of 420 euthymic patients with BD were assessed for this study, distributed as follows: functionally remitted (n = 221) and functionally impaired (n = 199). Finally, the multivariate logistic regression revealed that only five variables significantly contributed to the model, including: lifetime history of psychotic symptoms (the variable that contributed the most to the model), followed by the Hamilton Depression total score, and cognitive performance (executive functions and verbal memory). (4) Conclusions: treatments to ensure a good functional outcome in BD should specially prevent psychosis, target subthreshold depressive symptoms and enhance cognition, more specifically executive functions and verbal memory.

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.

Functional outcome assessment in bipolar disorder: A systematic literature review

OBJECTIVES

Functional impairment is an important driver of disability in patients with bipolar disorder (BD) and can persist even when symptomatic remission has been achieved. The objectives of this systematic literature review were to identify studies that assessed functioning in patients with BD and describe the functional scales used and their implementation.

METHODS

A systematic literature review of English-language articles published between 2000 and 2017 reporting peer-reviewed, original research related to functional assessment in patients with BD was conducted.

RESULTS

A total of 40 articles met inclusion criteria. Twenty-four different functional scales were identified, including 13 clinician-rated scales, 7 self-reported scales, and 4 indices based on residential and vocational data. The Global Assessment of Functioning (GAF) and the Functional Assessment Short Test (FAST) were the most commonly used global and domain-specific scales, respectively. All other scales were used in ≤2 studies. Most studies used ≥1 domain-specific scale. The most common applications of functional scales in these studies were evaluations of the relationships between global or domain-specific psychosocial functioning and cognitive functioning (eg, executive function, attention, language, learning, memory) or clinical variables (eg, symptoms, duration of illness, number of hospitalizations, number of episodes).

CONCLUSIONS

The results of this review show growing interest in the assessment of functioning in patients with BD, with an emphasis on specific domains such as work/educational, social, family, and cognitive functioning and high utilization of the GAF and FAST scales in published literature.

Cognitive variability in bipolar I disorder: A cluster-analytic approach informed by resting-state data

BACKGROUND

While the presence of cognitive performance deficits in bipolar disorder I (BD-I) is well established, there is no consensus about which cognitive abilities are affected. Heterogeneous phenotypes displayed in BD-I further suggest the existence of subgroups among the disorder. The present study sought to identify different cognitive profiles among BD-I patients as well as potentially underlying neuronal network changes.

METHODS

54 euthymic BD-I patients underwent cognitive testing and resting state neuroimaging. Hierarchical cluster-analysis was performed on executive function scores of bipolar patients. The derived clusters were compared against 54 age-, gender- and IQ-matched healthy controls (HC) to facilitate the interpretation of results. Further, resting state network properties were compared to identify differences probably underlying cognitive profiles.

RESULTS

A three-cluster solution emerged. Cluster 1 (n = 22) was characterized by deficits in cognitive flexibility and motor inhibition, cluster 2 (n = 12) displayed impulsive decision-making, while cluster 3 (n = 20) showed good visuospatial planning. Weaker connections in cluster 1 compared to cluster 2 were found between regions activated during tasks cluster 1 showed deficits on. Cluster 3 had a higher modularity than cluster 2, which correlated positively with problem solving performance and risk-taking in this cluster.

CONCLUSION

Obtained clusters showed distinct cognitive profiles, characterized by deficits and strengths, most of which remained precluded in a general comparison. Weaker interregional connections and separated subnetworks might underly behavioral deficits and strengths, respectively. The findings help explain the phenotypic heterogeneity observed in BD-I. This article is part of the Special Issue entitled 'Current status of the neurobiology of aggression and impulsivity'.

The use of component-wise gradient boosting to assess the possible role of cognitive measures as markers of vulnerability to pediatric bipolar disorder

BACKGROUND AND AIMS

Cognitive impairments are primary hallmarks symptoms of bipolar disorder (BD). Whether these deficits are markers of vulnerability or symptoms of the disease is still unclear. This study used a component-wise gradient (CGB) machine learning algorithm to identify cognitive measures that could accurately differentiate pediatric BD, unaffected offspring of BD parents, and healthy controls.

METHODS

59 healthy controls (HC; 11.19 ± 3.15 yo; 30 girls), 119 children and adolescents with BD (13.31 ± 3.02 yo, 52 girls) and 49 unaffected offspring of BD parents (UO; 9.36 ± 3.18 yo; 22 girls) completed the CANTAB cognitive battery.

RESULTS

CGB achieved accuracy of 73.2% and an AUROC of 0.785 in classifying individuals as either BD or non-BD on a dataset held out for validation for testing. The strongest cognitive predictors of BD were measures of processing speed and affective processing. Measures of cognition did not differentiate between UO and HC.

CONCLUSIONS

Alterations in processing speed and affective processing are markers of BD in pediatric populations. Longitudinal studies should determine whether UO with a cognitive profile similar to that of HC are at less or equal risk for mood disorders. Future studies should include relevant measures for BD such as verbal memory and genetic risk scores.

Compensatory cognitive training for people with severe mental illnesses in supported employment: A randomized controlled trial

Treatments for cognitive and functional impairments associated with severe mental illnesses are urgently needed. We tested a 12-week, manualized, Compensatory Cognitive Training (CCT) intervention targeting prospective memory, attention, learning/memory, and executive functioning in the context of supported employment for people with severe mental illnesses who were seeking work. 153 unemployed, work-seeking outpatients with schizophrenia/schizoaffective disorder (n=58), bipolar disorder (n=37), or major depression (n=58) were randomized to receive supported employment plus CCT or enhanced supported employment, a robust control group. Assessments of neuropsychological performance, functional capacity, psychiatric symptom severity, and self-reported functioning and quality of life were administered at baseline and multiple follow-up assessments over two years; work outcomes were collected for two years. Forty-seven percent of the participants obtained competitive work, but there were no differences in work attainment, weeks worked, or wages earned between the CCT and the enhanced supported employment group. ANCOVAs assessing immediate post-treatment effects demonstrated significant, medium to large, CCT-associated improvements on measures of working memory (p=0.038), depressive symptom severity (p=0.023), and quality of life (p=0.003). Longer-term results revealed no statistically significant CCT-associated improvements, but a trend (p=0.058) toward a small to medium CCT-associated improvement in learning. Diagnostic group (schizophrenia-spectrum vs. mood disorder) did not affect outcomes. We conclude that CCT has the potential to improve cognitive performance, psychiatric symptom severity, and quality of life in people with severe mental illnesses. Receiving CCT did not result in better work outcomes, suggesting that supported employment can result in competitive work regardless of cognitive status.

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.

GSK3β: a plausible mechanism of cognitive and hippocampal changes induced by erythropoietin treatment in mood disorders?

Mood disorders are associated with significant psychosocial and occupational disability. It is estimated that major depressive disorder (MDD) will become the second leading cause of disability worldwide by 2020. Existing pharmacological and psychological treatments are limited for targeting cognitive dysfunctions in mood disorders. However, growing evidence from human and animal studies has shown that treatment with erythropoietin (EPO) can improve cognitive function. A recent study involving EPO-treated patients with mood disorders showed that the neural basis for their cognitive improvements appeared to involve an increase in hippocampal volume. Molecular mechanisms underlying hippocampal changes have been proposed, including the activation of anti-apoptotic, antioxidant, pro-survival and anti-inflammatory signalling pathways. The aim of this review is to describe the potential importance of glycogen synthase kinase 3-beta (GSK3β) as a multi-potent molecular mechanism of EPO-induced hippocampal volume change in mood disorder patients. We first examine published associations between EPO administration, mood disorders, cognition and hippocampal volume. We then highlight evidence suggesting that GSK3β influences hippocampal volume in MDD patients, and how this could assist with targeting more precise treatments particularly for cognitive deficits in patients with mood disorders. We conclude by suggesting how this developing area of research can be further advanced, such as using pharmacogenetic studies of EPO treatment in patients with mood disorders.

Sex-related variation of neurocognitive functioning in bipolar disorder: Focus on visual memory and associative learning

Bipolar disorder (BD) is associated with cognitive deficits in attention, verbal memory and executive functions. However, only few studies have examined sex effects on cognition despite their clinical relevance. Given that visual memory/ learning has been understudied the aim of our study was to investigate sex-related variation in cognition (executive functions and visual memory/ learning) in BD. Cognitive performance of 60 bipolar-I patients and 30 healthy controls was evaluated by using CANTAB battery tasks targeting spatial memory (SRM), paired associative learning (PAL) and executive functions. We fitted a multivariate analysis of covariance (MANCOVA), followed by task-specific ANCOVAs. A significant diagnosis by sex interaction effect was detected (MANCOVA); specifically, diagnosis-specific sex effects were found for SRM and PAL, as healthy males outperformed healthy females but this pattern was attenuated in BD patients. Patients' clinicodemographic characteristics, current psychopathology or medication status did not differ across sexes and were, therefore, unlikely to explain detected sex effects. Our study is one of few studies to assess sex-related variation in cognition in BD and the first to record a diagnosis-specific sex effect for two tasks of visuo-spatial memory/ learning, indicating that sex-related variation in healthy subjects is disrupted in BD.

Assessment of cognitive functions in bipolar I disorder: A 1-year naturalistic follow-up study

OBJECTIVE

Available findings from cross-sectional studies have demonstrated cognitive impairments in bipolar I disorder (BD-I) during various phases of illness. However, very little is known about the longitudinal course of these cognitive impairments. The purpose of the study was to explore the longitudinal pattern of changes in cognitive functioning of BD-I patients.

METHODS

A total of 129 BD-I subjects (manic, depressed and euthymic groups) and 49 healthy controls were recruited using predefined selection criteria. All four study groups were assessed on various clinical and cognitive parameters (for attention, memory, executive functions and working memory) at study intake and at 3-monthly intervals over the next year.

RESULTS

All three patient groups performed poorly compared to controls on all cognitive measures at study intake and on some cognitive measures at the 3-, 6-, 9- and 12-month assessments. No significant time effects were observed for any cognitive test. A significant group by time interaction effect was found for executive functions (β = -44.74; P = .018) and working memory (β = 0.77; P ≤ .019) in the depressed group at 12 months; for visual memory (β = 1.21; P = .039) and working memory (β = 1.17; P ≤ .029) in the manic group at 12 months; and for working memory (β = -0.52; P ≤ .036) in the euthymic group at 12 months.

CONCLUSION

The patient groups showed significant impairments in all or some test domains relative to controls at all time-points. The cognitive functions largely remained stable in all patient groups, with slight improvement over time in a few tests. Further investigation is warranted in larger samples in longitudinal studies.

Gender differences in C-reactive protein and homocysteine modulation of cognitive performance and real-world functioning in bipolar disorder

BACKGROUND

Cognitive and psychosocial impairment has been associated with increased levels of C-reactive protein (CRP) and homocysteine in bipolar disorder, but gender differences have seldom been studied.

METHODS

Two hundred and twenty-four bipolar outpatients were included. Cognitive performance was assessed through the Screen for Cognitive Impairment in Psychiatry (SCIP). Psychosocial functioning was evaluated using the Functioning Assessment Short Test (FAST) and the General Assessment of Functioning (GAF). Homocysteine and CRP levels were determined. Separate analyses were performed by gender. Partial correlations were calculated to test for associations between biomarkers and cognitive and psychosocial functioning. Hierarchical multiple regression was used to assess factors predicting cognitive and psychosocial functioning. Covariates were: age, education, duration of illness, hospital admissions, depressive symptoms, tobacco consumption, and BMI.

RESULTS

A better performance was noted in women in delayed verbal learning (p = 0.010), along with better occupational functioning (p = 0.027) and greater leisure time impairment (p = 0.034). In men, CRP and homocysteine levels were associated with psychosocial dysfunction (interpersonal relationships and financial functioning, respectively). In women, CRP levels correlated with cognitive performance (SCIP total raw score, immediate and delayed verbal learning, and verbal fluency). CRP was a predictor of cognitive performance in women only.

LIMITATIONS

The choice of the cognitive scale and covariates and the lack of a control group may be the main limitations.

CONCLUSIONS

A gender difference was found in biomarker modulation of cognition and psychosocial functioning. A gender-based approach to cognition and real-world functioning should be considered in bipolar disorder to ensure an optimal outcome.

Canadian Network for Mood and Anxiety Treatments (CANMAT) and International Society for Bipolar Disorders (ISBD) 2018 guidelines for the management of patients with bipolar disorder

The Canadian Network for Mood and Anxiety Treatments (CANMAT) previously published treatment guidelines for bipolar disorder in 2005, along with international commentaries and subsequent updates in 2007, 2009, and 2013. The last two updates were published in collaboration with the International Society for Bipolar Disorders (ISBD). These 2018 CANMAT and ISBD Bipolar Treatment Guidelines represent the significant advances in the field since the last full edition was published in 2005, including updates to diagnosis and management as well as new research into pharmacological and psychological treatments. These advances have been translated into clear and easy to use recommendations for first, second, and third- line treatments, with consideration given to levels of evidence for efficacy, clinical support based on experience, and consensus ratings of safety, tolerability, and treatment-emergent switch risk. New to these guidelines, hierarchical rankings were created for first and second- line treatments recommended for acute mania, acute depression, and maintenance treatment in bipolar I disorder. Created by considering the impact of each treatment across all phases of illness, this hierarchy will further assist clinicians in making evidence-based treatment decisions. Lithium, quetiapine, divalproex, asenapine, aripiprazole, paliperidone, risperidone, and cariprazine alone or in combination are recommended as first-line treatments for acute mania. First-line options for bipolar I depression include quetiapine, lurasidone plus lithium or divalproex, lithium, lamotrigine, lurasidone, or adjunctive lamotrigine. While medications that have been shown to be effective for the acute phase should generally be continued for the maintenance phase in bipolar I disorder, there are some exceptions (such as with antidepressants); and available data suggest that lithium, quetiapine, divalproex, lamotrigine, asenapine, and aripiprazole monotherapy or combination treatments should be considered first-line for those initiating or switching treatment during the maintenance phase. In addition to addressing issues in bipolar I disorder, these guidelines also provide an overview of, and recommendations for, clinical management of bipolar II disorder, as well as advice on specific populations, such as women at various stages of the reproductive cycle, children and adolescents, and older adults. There are also discussions on the impact of specific psychiatric and medical comorbidities such as substance use, anxiety, and metabolic disorders. Finally, an overview of issues related to safety and monitoring is provided. The CANMAT and ISBD groups hope that these guidelines become a valuable tool for practitioners across the globe.