A preliminary longitudinal study on the cognitive and functional outcome of bipolar excellent lithium responders

A longitudinal study of cognition, functional outcome and quality of life in bipolar disorder and major depression

OBJECTIVE

Cognitive impairments are known to be a frequent cause of disability in bipolar disorder (BD) and major depression (MDD). Yet there is no consensus regarding the particular cognitive functions whose impairments can lead to disability in each domain of functioning. The aim of this study was to perform a longitudinal evaluation of working memory, inhibition, cognitive flexibility and attention in BD and MDD, investigate the relationship of these cognitive functions to disability and quality of life, and evaluate the impact of variables related to cognitive reserve (education and daily cognitive stimulation) on cognitive performance.

METHOD

31 participants (MDD = 12; BD = 19) were evaluated at baseline and after an average time of 2 years.

RESULTS

the BD group showed improvements in attention while patients with MDD improved on measures of attention and working memory. In BD working memory performance was associated with the cognition and mobility domains of functioning, and with physical and environmental quality of life. In MDD, cognitive flexibility was related to social relationships and environmental quality of life.

CONCLUSION

working memory and cognitive flexibility may be an interesting target for interventions aiming to improve everyday functioning and quality of life in BD and MDD.

[Effects of lithium, valproic acid, carbamazepine and antipsychotic agents on cognition in bipolar disorders-A systematic review]

BACKGROUND

Until now the long-term consequences of the medical treatment for bipolar disorder have barely been examined, especially the consequences with respect to cognitive impairment and dementia. Some studies show signs that some treatment options have a better effect on the brain than others. This review summarizes the current state of research.

OBJECTIVE

The effects of long-term consequences of lithium, valproic acid, carbamazepine and antipsychotic agents on the development of dementia or cognitive impairments in patients with bipolar disorder were investigated.

METHODS

A systematic literature search was carried out in the PubMed data base from May to July 2022.

RESULTS

The majority of studies showed that lithium has a neuroprotective effect and can lower the risk of developing dementia, whereas an increased risk was found in patients taking valproic acid. There are only very few studies that deal with antipsychotic medication and the long-term consequences concerning dementia.

CONCLUSION

Lithium should be recommended for the long-term treatment of bipolar disorder. Valproic acid should not or carefully be used as it can affect the risk of developing dementia. With respect to antipsychotics there is no recommendation as more studies are needed to evaluate the long-term consequences.

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.

Limited time-specific and longitudinal effects of depressive and manic symptoms on cognition in bipolar spectrum disorders

OBJECTIVES

Previous research suggests that cognitive performance worsens during manic and depressed states in bipolar disorder (BD). However, studies have often relied upon between-subject, cross-sectional analyses and smaller sample sizes. The current study examined the relationship between mood symptoms and cognition in a within-subject, longitudinal study with a large sample.

METHODS

Seven hundred and seventy-three individuals with BD completed a neuropsychological battery and mood assessments at baseline and 1-year follow-up. The battery captured eight domains of cognition: fine motor dexterity, visual memory, auditory memory, emotion processing, and four aspects of executive functioning: verbal fluency and processing speed; conceptual reasoning and set shifting; processing speed with influence resolution; and inhibitory control. Structural equation modeling was conducted to examine the cross-sectional and longitudinal relationships between depressive symptoms, manic symptoms, and cognitive performance. Age and education were included as covariates. Eight models were run with the respective cognitive domains.

RESULTS

Baseline mood positively predicted 1-year mood, and baseline cognition positively predicted 1-year cognition. Mood and cognition were generally not related for the eight cognitive domains. Baseline mania was predictive in one of eight baseline domains (conceptual reasoning and set shifting); baseline cognition predicted 1-year symptoms (inhibitory control-depression symptoms, visual memory-manic symptoms).

CONCLUSIONS

In a large community sample of patients with bipolar spectrum disorder, cognitive performance appears to be largely unrelated to depressive and manic symptoms, suggesting that cognitive dysfunction is stable in BD and is not dependent on mood state in BD. Future work could examine how treatment affects relationship between cognition and mood.

SIGNIFICANT OUTCOMES

Cognitive dysfunction appears to be largely independent of mood symptoms in bipolar disorder.

LIMITATIONS

The sample was generally highly educated (M = 15.22), the majority of the subsample with elevated manic symptoms generally presented with concurrent depressive elevated symptoms, and the study did not stratify recruitment based on mood state.

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.

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.

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 black sheep of the family- whole-exome sequencing in family of lithium response discordant bipolar monozygotic twins

Twin studies are among the most promising strategies for studying heritable disorders, including bipolar disorder (BD). The aim of the present study was to identify distinguishing genes between monozygotic (MZ) twins with different BD phenotype and compare them to their non-affected siblings. Whole-exome sequencing (WES) can identify rare and structural variants that could detect the polygenetic burden of complex disorders. WES was performed on a family composed of two MZ twins with BD, their unaffected brother and unaffected parents. The twins have a discordant response to lithium and distinct course of illness. Following WES, six genes of particular interest emerged: Neurofibromin type 1 (NF1), Biorientation of chromosomes in cell division 1 (BOD1), Golgi-associated gamma adaptin ear-containing ARF binding protein 3 (GGA3), Disrupted in schizophrenia 1 (DISC1), Neuromedin U receptor 2 (NMUR2), and Huntingtin interacting protein 1-related (HIP1R). Interestingly, many of these influence glutamatergic pathways and thus the findings may have therapeutical implications. These results may provide important insights to unveil genetic underpinnings of BD and the response to lithium.

Diet and Neurocognition in Mood Disorders - An Overview of the Overlooked

Bipolar disorder and major depression are associated with significant disability, morbidity, and reduced life expectancy. People with mood disorders have shown higher ratios of unhealthy lifestyle choices, including poor diet quality and suboptimal nutrition. Diet and nutrition impact on brain /mental health, but cognitive outcomes have been less researched in psychiatric disorders. Neurocognitive dysfunction is a major driver of social dysfunction and a therapeutic target in mood disorders, although effective cognitive-enhancers are currently lacking. This narrative review aimed to assess the potential cognitive benefits of dietary and nutritional interventions in subjects diagnosed with mood disorders. Eight clinical trials with nutrients were identified, whereas none involved dietary interventions. Efficacy to improve select cognitive deficits has been reported, but results are either preliminary or inconsistent. Methodological recommendations for future cognition trials in the field are advanced. Current evidence and future views are discussed from the perspectives of precision medicine, clinical staging, nutritional psychiatry, and the brain-gut-microbiota axis.

Cognitive Impairment in Patients with Bipolar Disorder: Impact of Pharmacological Treatment

Bipolar disorder is an illness characterised by periods of elated and depressed mood. These mood episodes are associated with changes in cognitive function and there is evidence to suggest that cognitive dysfunction persists during euthymia. The extent to which this is a function of the illness or a result of treatment is less clear. In this narrative review, we explore the impact of commonly used medications for bipolar disorder on cognitive function. Specific impairments in executive function and verbal memory have been noted in bipolar disorder. The impact of pharmacological treatments upon cognitive function is mixed with a number of studies reporting conflicting results. Interpretation of the data is further complicated by the variety of cognitive tests employed, study design, the relatively small numbers of patients included and confounding by indication. Overall, there is some evidence that while lithium improves some cognitive domains, it impedes others. Antipsychotics may be deleterious to cognition, although this may relate to the patient population in which they are prescribed. Sodium valproate is also associated with worse cognitive outcomes, while the impact of other antiepileptics is unclear. Overall the quality of evidence is poor and is derived from a relatively small number of studies that often do not account for the significant heterogeneity of the disorder or common comorbidities. The use of consistent methodologies and measures of cognition across studies, as well as in naturalistic settings, would enable more certain conclusions to be drawn.

High BDNF serum levels are associated to good cognitive functioning in bipolar disorder

Background:

Neurotrophins such as brain-derived neurotrophic factor (BDNF), inflammation and oxidative damage may contribute to the pathophysiology of bipolar disorder (BD) in terms of illness activity. To date, there is a lack of studies linking the cognitive impairment observed in BD with these neurobiological mechanisms. This study aimed to investigate the role of these neurobiological factors in clinical and cognitive outcomes in a sample of bipolar individuals.

Methods:

We measured serum BDNF, cytokines and oxidative stress markers in a sample of 133 individuals: 52 euthymic bipolar patients, 32 manic patients and 49 healthy controls. They were all assessed with a comprehensive cognitive battery. Sociodemographic and clinical data were collected. Multiple linear regression models were built to study associations of neurotrophins and inflammatory and oxidative measures with cognitive functioning.

Results:

BDNF levels were decreased in euthymic (p = 0.039) and manic (p < 0.001) individuals. Conversely, inflammatory (interleukin 6 (IL-6)) (p = 0.019) and oxidative stress (p = 0.003) measures were increased in bipolar individuals compared to controls. BDNF levels were associated with executive functioning (β = 0.01, p = 0.02) and verbal memory (β = 0.013, p = 0.005), together with other demographic variables. In particular, verbal memory was also associated with obesity (β=-0.04, p = 0.005). Neither inflammatory markers, oxidative stress markers nor other relevant clinical variables showed any association with cognitive outcome.

Conclusions:

Of all the peripheral neurobiological factors analysed, BDNF was the only one significantly associated with cognitive dysfunction in bipolar disorder individuals. This study emphasizes the role of BDNF not only across mood phases but also in cognitive functioning.

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.

Can lithium salts prevent depressive episodes in the real world?

To critically examine the effectiveness of lithium in preventing depressive symptoms (mixed and depressive episodes) in real life settings, taking into account adherence to drug treatment and its implications for the clinical costs of the disease. Overall, 72 patients with bipolar disorder initially treated with lithium carbonate were included and followed-up for 10 years. Patients were assessed every 8 weeks for morbidity and alcohol/drug consumption. Patients with good adherence to lithium had fewer episodes with depressive features than poor adherers (B = 2.405, p = 0.046) and also fewer manic and hypomanic episodes (B = 2.572; p < 0.001), after controlling for confounders. Time to relapse into a depressive or mixed episode and into a manic or hypomanic episode was shorter in patients with poor adherence. The costs of the 1.95 ± 2.38 (mean ± standard deviation) admissions of adherent patients through the 10 years of follow-up were €10,349, while the costs of the 6.25 ± 4.92 admissions of non-adherent patients were €44,547. In clinical practice settings, long-term lithium salts seem to have a preventive effect on depressive symptoms.

Longitudinal relationship between clinical course and neurocognitive impairments in bipolar disorder

BACKGROUND

The aim of this study was to estimate the relationship between clinical course and trajectory of neurocognitive functioning during a follow-up period in a sample of euthymic bipolar patients.

METHODS

Fifty-one patients with BD performed two-neurocognitive assessment separated by a period of at least 48 months. The clinical course during the follow-up period was documented by: three measures 1) number of affective episodes, 2) time spent ill, and 3) mood instability.

RESULTS

Patients were followed-up for a mean period of 73.21 months. Neurocognitive performance tended to be stable throughout the follow-up. Performance in verbal memory and executive functions at the end of study were related with the number of hypo/manic episodes and time spent with hypo/manic symptoms during the follow-up. None of the clinical measures considered were related to changes in neurocognitive performance over the follow-up period.

LIMITATIONS

The relatively small sample size limits the value of subgroup analysis. The study design does not rule out some risk of selection bias.

CONCLUSIONS

Although there may be a positive relationship between number of episodes and neurocognitive deficits in patients with bipolar disorder, successive episodes do not seem to modify the trajectory of neurocognitive functioning over time. Theoretical implications of these findings are discussed.