Abdominal obesity is associated with impaired cognitive function in euthymic bipolar individuals

Machine-based learning of multidimensional data in bipolar disorder - pilot results

INTRODUCTION

Owing to the heterogenic picture of bipolar disorder, it takes approximately 8.8 years to reach a correct diagnosis. Early recognition and early intervention might not only increase quality of life, but also increase life expectancy as a whole in individuals with bipolar disorder. Therefore, we hypothesize that implementing machine learning techniques can be used to support the diagnostic process of bipolar disorder and minimize misdiagnosis rates.

MATERIALS AND METHODS

To test this hypothesis, a de-identified data set of only demographic information and the results of cognitive tests of 196 patients with bipolar disorder and 145 healthy controls was used to train and compare five different machine learning algorithms.

RESULTS

The best performing algorithm was logistic regression, with a macro-average F1-score of 0.69 [95% CI 0.66-0.73]. After further optimization, a model with an improved macro-average F1-score of 0.75, a micro-average F1-score of 0.77, and an AUROC of 0.84 was built. Furthermore, the individual amount of contribution per variable on the classification was assessed, which revealed that body mass index, results of the Stroop test, and the d2-R test alone allow for a classification of bipolar disorder with equal performance.

CONCLUSION

Using these data for clinical application results in an acceptable performance, but has not yet reached a state where it can sufficiently augment a diagnosis made by an experienced clinician. Therefore, further research should focus on identifying variables with the highest amount of contribution to a model's classification.

Neurocognitive correlates of metabolic dysregulation in individuals with mood disorders: a systematic review and meta-analysis

Individuals with mood disorders are predisposed to metabolic dysfunction, while those with metabolic dysregulation such as diabetes and obesity experience more severe depressive symptoms. Both metabolic dysfunction and mood disorders are independently associated with cognitive deficits. Therefore, given their close association, this study aimed to explore the association between metabolic dysfunction in individuals with mood disorders in relation to cognitive outcomes. A comprehensive search comprised of these three domains was carried out; a random-effects meta-analysis pooling mean cognitive outcomes was conducted (PROSPERO ID: CRD42022295765). Sixty-three studies were included in this review; 26 were synthesized in a quantitative meta-analysis. Comorbid metabolic dysregulation was associated with significantly lower global cognition among individuals with mood disorders. These trends were significant within each mood disorder subgroup, including major depressive disorder, bipolar disorder, and self-report depression/depressive symptoms. Type 2 diabetes was associated with the lowest cognitive performance in individuals with mood disorders, followed by peripheral insulin resistance, body mass index ⩾25 kg/m2, and metabolic syndrome. Significant reduction in scores was also observed among individual cognitive domains (in descending order) of working memory, attention, executive function, processing speed, verbal memory, and visual memory. These findings demonstrate the detrimental effects of comorbid metabolic dysfunction in individuals with mood disorders. Further research is required to understand the underlying mechanisms connecting mood disorders, metabolism, and cognition.

Shared and unique characteristics of metabolic syndrome in psychotic disorders: a review

Introduction

People with psychosis spectrum disorders (PSD) face an elevated risk of metabolic syndrome (MetS), which may reduce their life expectancy by nearly 20%. Pinpointing the shared and specific characteristics and clinical implications of MetS in PSD is crucial for designing interventions to reduce this risk, but an up-to-date review on MetS across the psychosis spectrum is lacking.

Methods

This narrative review fills this gap by examining the clinical literature on characteristics and implications of MetS in both distinct PSD and transdiagnostically, i.e., across traditional categorical diagnoses, with a focus on psychiatric and cardio-metabolic management.

Results

We discuss common and specific characteristics of MetS in PSD, as well as factors contributing to MetS development in PSD patients, including unhealthy lifestyle factors, genetic predisposition, pro-inflammatory state, drugs consumption, antipsychotic medication, and psychotic symptoms. We highlight the importance of early identification and management of cardio-metabolic risk in PSD patients, as well as the existing gaps in the literature, for instance in the screening for MetS in younger PSD patients. We compare hypotheses-generating clinical associations and characteristics of MetS in different PSD, concluding by reviewing the existing recommendations and challenges in screening, monitoring, and managing MetS in PSD.

Conclusion

Early identification and management of MetS are crucial to mitigate the long-term cardio-metabolic toll in PSD patients. Interventions should focus on healthy lifestyle and appropriate pharmacological and behavioral interventions. Further translational and clinical research is needed to develop targeted interventions and personalized treatment approaches for this vulnerable population, aiming at improving physical health and overall well-being.

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.

The clinical characterization of the adult patient with bipolar disorder aimed at personalization of management

Bipolar disorder is heterogeneous in phenomenology, illness trajectory, and response to treatment. Despite evidence for the efficacy of multimodal-ity interventions, the majority of persons affected by this disorder do not achieve and sustain full syndromal recovery. It is eagerly anticipated that combining datasets across various information sources (e.g., hierarchical "multi-omic" measures, electronic health records), analyzed using advanced computational methods (e.g., machine learning), will inform future diagnosis and treatment selection. In the interim, identifying clinically meaningful subgroups of persons with the disorder having differential response to specific treatments at point-of-care is an empirical priority. This paper endeavours to synthesize salient domains in the clinical characterization of the adult patient with bipolar disorder, with the overarching aim to improve health outcomes by informing patient management and treatment considerations. Extant data indicate that characterizing select domains in bipolar disorder provides actionable information and guides shared decision making. For example, it is robustly established that the presence of mixed features - especially during depressive episodes - and of physical and psychiatric comorbidities informs illness trajectory, response to treatment, and suicide risk. In addition, early environmental exposures (e.g., sexual and physical abuse, emotional neglect) are highly associated with more complicated illness presentations, inviting the need for developmentally-oriented and integrated treatment approaches. There have been significant advances in validating subtypes of bipolar disorder (e.g., bipolar I vs. II disorder), particularly in regard to pharmacological interventions. As with other severe mental disorders, social functioning, interpersonal/family relationships and internalized stigma are domains highly relevant to relapse risk, health outcomes, and quality of life. The elevated standardized mortality ratio for completed suicide and suicidal behaviour in bipolar disorder invites the need for characterization of this domain in all patients. The framework of this paper is to describe all the above salient domains, providing a synthesis of extant literature and recommendations for decision support tools and clinical metrics that can be implemented at point-of-care.

The Role of Tryptophan Metabolites in Neuropsychiatric Disorders

In recent decades, neuropsychiatric disorders such as major depressive disorder, schizophrenia, bipolar, etc., have become a global health concern, causing various detrimental influences on patients. Tryptophan is an important amino acid that plays an indisputable role in several physiological processes, including neuronal function and immunity. Tryptophan’s metabolism process in the human body occurs using different pathways, including the kynurenine and serotonin pathways. Furthermore, other biologically active components, such as serotonin, melatonin, and niacin, are by-products of Tryptophan pathways. Current evidence suggests that a functional imbalance in the synthesis of Tryptophan metabolites causes the appearance of pathophysiologic mechanisms that leads to various neuropsychiatric diseases. This review summarizes the pharmacological influences of tryptophan and its metabolites on the development of neuropsychiatric disorders. In addition, tryptophan and its metabolites quantification following the neurotransmitters precursor are highlighted. Eventually, the efficiency of various biomarkers such as inflammatory, protein, electrophysiological, genetic, and proteomic biomarkers in the diagnosis/treatment of neuropsychiatric disorders was discussed to understand the biomarker application in the detection/treatment of various diseases.

Nutrition, Overweight, and Cognition in Euthymic Bipolar Individuals Compared to Healthy Controls

Bipolar disorder (BD) is associated with impairments in cognitive functions, in which metabolic factors, e.g., overweight, seem to play a significant role. The aim of this study was to investigate the association between nutritional factors and cognitive performance in euthymic individuals with BD. A study cohort of 56 euthymic individuals with BD was compared to a sample of 53 mentally healthy controls. To assess cognitive function, the following tests were applied: California Verbal Learning Test, Trail Making Test A/B, d2 Test of Attention-Revised, and Stroop’s Color-Word Interference Test. Furthermore, a 4-day food record was processed to evaluate dietary intake of macronutrients, specific micronutrients, and food diversity. Body mass index and waist to height ratio were calculated to assess overweight and central obesity. Results showed no nutritional differences between individuals with BD and controls. Individuals with BD performed worse in the d2 test than controls. Hierarchical regression analyses yielded no association between cognitive and nutritional parameters. However, waist to height ratio was negatively correlated with almost all cognitive tests. Central obesity seems to affect cognitive functioning in BD, while the lack of finding differences in nutritional data might be due to problems when collecting data and the small sample size. Consequently, further studies focusing on objectively measuring food intake with adequate sample size are needed.

Combined influence of medication and symptom severity on visual processing in bipolar disorder

Previous studies have reported visual impairments in patients with bipolar disorder (BPD), but unclear were whether clinical variables would be associated with those disturbances. Here, we investigate the relationship between visual functioning, in terms of color discrimination, and the impact of BPD duration, mood state, and the patients' medication. Forty-five participants (25-45 years old) were recruited for this study. Color discrimination was performed using the Cambridge Colour Test. Serial multiple mediations were run to investigate the assumption of association between color discrimination and the clinical variables. Our findings showed that, compared with healthy controls, BPD patients' performance was worse for the Protan, Deutan, and Tritan vectors, revealing deterioration of color discrimination. In addition, the mediation analyses revealed a strong direct (p < .001) and moderate-to-high indirect effects (p < .01) of medication and symptom severity on color discrimination. Overall, both longer the duration of the disease and greater the symptom severity of BPD patients resulted in worse performance. It highlights the importance of examining the wider clinical context of an affective disorder to understand how it affects visual processing in this population.

Violent suicide attempt history in elderly patients with bipolar disorder: The role of sex, abdominal obesity, and verbal memory: Results from the FACE-BD cohort (FondaMental Advanced center of Expertise for Bipolar Disorders)

BACKGROUND

Bipolar disorder (BD) is a chronic, lifelong condition, associated with increased risk of obesity, cognitive impairment, and suicidal behaviors. Abdominal obesity and a higher risk of violent suicide attempt (SA) seem to be shared correlates with older age, BD, and male sex until middle age when menopause-related female body changes occur. This study aimed at assessing the role of abdominal obesity and cognition in the violent SA burden of individuals with BD.

METHODS

From the well-defined nationwide cohort FACE-BD (FondaMental Advanced center of Expertise for Bipolar Disorders), we extracted data on 619 euthymic BD patients that were 50 years or older at inclusion. Cross-sectional clinical, cognitive, and metabolic assessments were performed. SA history was based on self-report.

RESULTS

Violent SA, in contrast to non-violent and no SA, was associated with higher waist circumference, abdominal obesity and poorer California Verbal Learning Test short-delay free recall (CVLT-SDFR) (ANOVA, p < .001, p = .014, and p = .006). Waist circumference and abdominal obesity were associated with violent SA history independently of sex, BD type and anxiety disorder (Exp(B) 1.02, CI 1.00-1.05, p = .018; Exp(B) 2.16, CI 1.00-4.64, p = .009, accordingly). In an exploratory model, waist circumference and CVLT-SDFR performance mediated the association between male sex and violent SA.

LIMITATIONS

Cross-sectional design and retrospective reporting.

CONCLUSIONS

Violent SA history was associated with abdominal obesity and poorer verbal memory in older age BD patients. These factors were interlinked and might mediate the association between male sex and violent SA.

Does metabolic syndrome or its component factors alter the course of bipolar disorder? A systematic review

Metabolic syndrome (MetS) and its component factors, obesity, hypertension, dyslipidaemia and insulin resistance, have shown a bidirectional relationship with the prevalence and severity of bipolar disorder (BD). A systematic search of electronic databases (Pubmed, PsycINFO, clinicaltrials.gov) was conducted to explore and integrate current evidence about the role of MetS and its component factors with clinical outcomes of BD. Thirty-four articles met the inclusion criteria. Studies were grouped by the metabolic factors assessed, which included MetS, obesity and body mass index (BMI), dyslipidaemia, impaired glucose metabolism (IGM), diabetes mellitus and hypertension. They were then classified according to outcomes such as course of episodes, rapid cycling, suicidal behavior, treatment response, and global and cognitive functioning. Although current evidence remains controversial in most aspects of clinical outcomes, metabolic risk factors could alter the course of BD, with worse global functioning, poorer treatment response and a chronic course of illness, as well as enhancing rapid cycling. Further research is needed to elucidate the role of each risk factor in the mentioned outcomes.

Tryptophan Metabolism in Bipolar Disorder in a Longitudinal Setting

Immune-mediated inflammatory processes and oxidative stress are involved in the aetiopathogenesis of bipolar disorder (BD) and weight-associated comorbidities. Tryptophan breakdown via indoleamine 2,3-dioxygenase-1 (IDO-1) along the kynurenine axis concomitant with a pro-inflammatory state was found to be more active in BD, and associated with overweight/obesity. This study aimed to investigate tryptophan metabolism in BD compared to controls (C), stratified by weight classes, in a longitudinal setting, dependent on the incidence of BD episodes. Peripheral tryptophan, kynurenine, and neopterin were assessed in the serum of 226 BD individuals and 142 C. Three samples in a longitudinal assessment were used for 75 BD individuals. Results showed a higher kynurenine/tryptophan in both BD compared to C and overweight compared to normal weight persons. Levels remained stable over time. In the longitudinal course, no differences were found between individuals who were constantly euthymic or not, or who had an illness episode or had none. Findings indicate that tryptophan, kynurenine, and IDO-1 activity may play a role in pathophysiology in BD but are not necessarily associated with clinical manifestations. Accelerated tryptophan breakdown along the kynurenine axis may be facilitated by being overweight. This may increase the risk of accumulation of neurotoxic metabolites, impacting BD symptomatology, cognition, and somatic comorbidities.

Metabolic Syndrome Impairs Executive Function in Bipolar Disorder

Background: Metabolic syndrome (MetS) is more prevalent in individuals with bipolar disorder and has a negative impact on cognition, in particular on executive function, which is already impaired in individuals with bipolar disorder compared to healthy controls.

Methods: In a cross-sectional study, we compared 148 euthymic patients with bipolar disorder and 117 healthy controls in cognitive function depending on the diagnosis of MetS. A neuropsychological test battery was used including the Trail Making Test A/B, Stroop Color and Word Interference Test, the d2 Test of Attention Revised, and the California Verbal Learning Test. In addition, MetS variables as well as the defining variables waist circumference, serum triglyceride levels, high-density lipoprotein cholesterol levels, blood pressure, fasting glucose levels, and body mass index were compared between patients and controls. In addition, illness-related variables were associated with MetS in individuals with bipolar disorder.

Results: The prevalence of MetS in patients with bipolar disorder was higher than in controls (30.4 vs. 15.4%). Patients with bipolar disorder with MetS had impaired executive function compared to patients without MetS or healthy controls with and without MetS (p = 0.020). No MetS effects or interaction MetS × Group was found in attention/processing speed (p = 0.883) and verbal learning/memory (p = 0.373). Clinical variables (illness duration, suicidality, number of affective episodes, medication, age of onset, and history of psychosis) did not relate to MetS in bipolar disorder (p > 0.05).

Conclusion: Bipolar disorder comorbid with MetS bears additional risk for impaired executive function. Executive function includes action planning, inhibition, and impulse control and could play a critical role in keeping long-term goals in mind associated with gaining and maintaining a healthy weight.

Physical Health Profile and Associated Behavior During the COVID-19 Pandemic in Patients With Bipolar Disorder

Background: The COVID-19 pandemic has led to an increased psychological strain on public mental health and may impact behavioral, mental, and physical health, presumably with effects on patients with severe mental disorders. This study examines pandemic-related physical and mental health and (compensatory) behavioral changes, in patients with BD as compared to healthy control individuals. Method: Physical and mental health and self-reported changes in daily structure and behavior due to the pandemic were assessed using a self-constructed questionnaire and the brief symptom inventory (BSI) in Germany, Austria, and Denmark in individuals with BD and a healthy control group. Results: The present study included 118 individuals with BD and 215 healthy controls. Individuals with BD reported statistically significant higher physical risk burden, increased weight gain, more physical comorbidities, and a decrease in physical activity and they further reported higher rates of COVID-19 testing, had more worries concerning health, and experienced more anxiety but less social distancing. Conclusion: The COVID-19 pandemic seems to have a greater impact on physical health in individuals with BD than in healthy controls. Individuals with BD appear to be having more difficulties compensating their behavior due to the pandemic which could amplify the effect of risk factors associated with poorer physical health. This highlights the necessity for optimizing and targeting the overall treatment of both mental and physical health in patients with BD during periods with far-reaching changes such as the COVID-19 pandemic. Limitations: Sampling issues and self-report forms, selectivity (missing elderly, and those lacking access or knowledge of technology).

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.

Exploring brain insulin resistance in adults with bipolar depression using extracellular vesicles of neuronal origin

Accumulating evidence suggests that disrupted insulin signaling is involved in bipolar disorder (BD) pathogenesis. Herein, we aimed to directly explore the potential role of neuronal insulin signaling using an innovative technique based on biomarkers derived from plasma extracellular vesicles enriched for neuronal origin (NEVs). We leveraged plasma samples from a randomized, double-blind, placebo-controlled, 12-week clinical trial evaluating infliximab as a treatment of bipolar depression. We isolated NEVs using immunoprecipitation against neuronal marker L1CAM from samples collected at baseline and weeks 2, 6 and 12 (endpoint) and measured NEV biomarkers using immunoassays. We assessed neuronal insulin signaling at its first node (IRS-1) and along the canonical (Akt, GSK-3β, p70S6K) and alternative (ERK1/2, JNK and p38-MAPK) pathways. A subset of participants (n = 27) also underwent whole-brain magnetic resonance imaging (MRI) at baseline and endpoint. Pre-treatment, NEV biomarkers of insulin signaling were independently associated with cognitive function and MRI measures (i.e. hippocampal and ventromedial prefrontal cortex [vmPFC] volumes). In fact, the association between IRS-1 phosphorylation at serine site 312 (pS312-IRS-1), an indicator of insulin resistance, and cognitive dysfunction was mediated by vmPFC volume. In the longitudinal analysis, patients treated with infliximab, a tumor necrosis factor-alpha antagonist with known insulin sensitizing properties, compared to those treated with placebo, had augmented phosphorylation of proteins from the alternative pathway. Infliximab responders had significant increases in phosphorylated JNK levels, relative to infliximab non-responders and placebo responders. In addition, treatment with infliximab resulted in increase in MRI measures of brain volume; treatment-related changes in the dorsolateral prefrontal cortex volume were mediated by changes in biomarkers from the insulin alternative pathway. In conclusion, our findings support the idea that brain insulin signaling is a target for further mechanistic and therapeutic investigations.

The Relationship Between Food Craving, Appetite-Related Hormones and Clinical Parameters in Bipolar Disorder

Obesity and weight gain in bipolar disorder (BD) have multifactorial underlying causes such as medication side effects, atypical depressive symptomatology, genetic variants, and disturbances in the neuro-endocrinal system. Therefore, we aim to explore the associations between food craving (FC), clinical parameters, psychotropic medication, and appetite-related hormones. In this cross-sectional investigation, 139 individuals with BD and 93 healthy controls (HC) completed the food craving inventory (FCI). In addition, blood samples (including leptin and acylated ghrelin) were analyzed and sociodemographic and anthropometric data were collected. Individuals with BD reported higher frequencies of total FC as well as craving for fat and fast food than HC. Additionally, we found a significant negative correlation between FC and ghrelin levels in BD. Smokers with BD reported significantly more craving for high fat foods than non-smokers. Age was significantly associated with FC independent of group. Individuals with BD taking olanzapine and quetiapine reported higher frequencies of craving for sweet food, while patients currently taking lithium reported less total FC compared to those without lithium therapy. Likewise, patients currently taking valproate reported less total FC and less craving for sweets than those not taking valproate. FC appears to be of clinical relevance in individuals with BD. Contrary to previous data, this does not seem to be a female phenomenon only and might encompass more than the specific craving for carbohydrates. Although due to the cross sectional design, causality cannot be determined, the association between depressive symptomatology and fast food craving warrants further research.

Call to action regarding the vascular-bipolar link: A report from the Vascular Task Force of the International Society for Bipolar Disorders

OBJECTIVES

The association of bipolar disorder with early and excessive cardiovascular disease was identified over a century ago. Nonetheless, the vascular-bipolar link remains underrecognized, particularly with regard to how this link can contribute to our understanding of pathogenesis and treatment.

METHODS

An international group of experts completed a selective review of the literature, distilling core themes, identifying limitations and gaps in the literature, and highlighting future directions to bridge these gaps.

RESULTS

The association between bipolar disorder and vascular disease is large in magnitude, consistent across studies, and independent of confounding variables where assessed. The vascular-bipolar link is multifactorial and is difficult to study given the latency between the onset of bipolar disorder, often in adolescence or early adulthood, and subsequent vascular disease, which usually occurs decades later. As a result, studies have often focused on risk factors for vascular disease or intermediate phenotypes, such as structural and functional vascular imaging measures. There is interest in identifying the most relevant mediators of this relationship, including lifestyle (eg, smoking, diet, exercise), medications, and systemic biological mediators (eg, inflammation). Nonetheless, there is a paucity of treatment studies that deliberately engage these mediators, and thus far no treatment studies have focused on engaging vascular imaging targets.

CONCLUSIONS

Further research focused on the vascular-bipolar link holds promise for gleaning insights regarding the underlying causes of bipolar disorder, identifying novel treatment approaches, and mitigating disparities in cardiovascular outcomes for people with bipolar disorder.

Differences in Kynurenine Metabolism During Depressive, Manic, and Euthymic Phases of Bipolar Affective Disorder

Background & Objectives:

The kynurenine pathway is involved in inflammatory diseases. Alterations of this pathway were shown in psychiatric entities as well. The aim of this study was to determine whether specific changes in kynurenine metabolism are associated with current mood symptoms in bipolar disorder.

Methods:

Sum scores of the Hamilton Depression Scale, Beck Depression Inventory, and Young Mania Rating Scale were collected from 156 bipolar individuals to build groups of depressive, manic and euthymic subjects according to predefined cut-off scores. Severity of current mood symptoms was correlated with activities of the enzymes kynurenine 3-monooxygenase (ratio of 3-hydroxykynurenine/ kynurenine), kynurenine aminotransferase (ratio of kynurenic acid/ kynurenine) and kynureninase (ratio of 3-hydroxyanthranilic acid/ 3-hydroxykynurenine), proxied by ratios of serum concentrations.

Results:

Individuals with manic symptoms showed a shift towards higher kynurenine 3-monooxygenase activity (χ2 = 7.14, Df = 2, p = .028), compared to euthymic as well as depressed individuals. There were no differences between groups regarding activity of kynurenine aminotransferase and kynureninase. Within the group of depressed patients, Hamilton Depression Scale and kynurenine aminotransferase showed a significant negative correlation (r = -0.41, p = .036), displaying lower metabolism in the direction of kynurenic acid.

Conclusion:

Depression severity in bipolar disorder seems to be associated with a decreased synthesis of putative neuroprotective kynurenic acid. Furthermore, higher kynurenine 3-monooxygenase activity in currently manic individuals indicates an increased inflammatory state within bipolar disorder with more severe inflammation during manic episodes. The underlying pathophysiological mechanisms of the different affective episodes could represent parallel mechanisms rather than opposed processes.

Current understandings of the trajectory and emerging correlates of cognitive impairment in bipolar disorder: An overview of evidence

OBJECTIVES

Cognitive dysfunction affects a significant proportion of people with bipolar disorder (BD), but the cause, trajectory and correlates of such dysfunction remains unclear. Increased understanding of these factors is required to progress treatment development for this symptom dimension.

METHODS

This paper provides a critical overview of the literature concerning the trajectories and emerging correlates of cognitive functioning in BD. It is a narrative review in which we provide a qualitative synthesis of current evidence concerning clinical, molecular, neural and lifestyle correlates of cognitive impairment in BD across the lifespan (in premorbid, prodromal, early onset, post-onset, elderly cohorts).

RESULTS

There is emerging evidence of empirical links between cognitive impairment and an increased inflammatory state, brain structural abnormalities and reduced neuroprotection in BD. However, evidence regarding the progressive nature of cognitive impairment is mixed, since consensus between different cross-sectional data is lacking and does not align to the outcomes of the limited longitudinal studies available. Increased recognition of cognitive heterogeneity in BD may help to explain some inconsistencies in the extant literature.

CONCLUSIONS

Large, longitudinally focussed studies of cognition and its covariation alongside biological and lifestyle factors are required to better define cognitive trajectories in BD, and eventually pave the way for the application of a precision medicine approach for individual patients in clinical practice.

Overlapping mechanisms linking insulin resistance with cognition and neuroprogression in bipolar disorder

Cognitive impairment is highly prevalent in the progression of both diabetes mellitus and bipolar disorder. The relationship between insulin resistance in diabetes and the risk of developing major neurocognitive disorders such as Alzheimer's disease has been well described. Insulin resistance and the associated metabolic deficiencies lead to biochemical alteration which hasten neurodegeneration and subsequent cognitive impairment. For bipolar disorder, some patients experience a cyclical, yet progressive course of illness. These patients are also more likely to have medical comorbidities such as cardiovascular disease and diabetes, and insulin resistance in particular may precede the neuroprogressive course. Diabetes and bipolar disorder share epidemiological, biochemical, and structural signatures, as well as cognitive impairment within similar domains, suggesting a common mechanism between the two conditions. Here we describe the association between insulin resistance and cognitive changes in bipolar disorder, as well as potential implications for therapeutic modulation of neuroprogression.

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.

Adiponectin is decreased in bipolar depression

Objectives: Bipolar disorder (BD) is often accompanied by medical comorbidities, which affect illness course and prognosis. Adipokines may not only be involved in the aetiopathogenetic mechanisms of these comorbidities; there might be an association between adipokines and the neuropsychiatric core features of BD such as mood disturbances and cognitive deficits.Methods: In this investigation, fasting blood samples from 120 individuals with BD (75 euthymic and 45 with mild depressive symptoms) and 68 control subjects were taken and adiponectin and leptin concentrations were analysed.Results: We found that, in female participants, adiponectin levels differed significantly between patients and controls indicating lower levels in individuals with BD, even after controlling for BMI (F(1,92) = 4.65, P = 0.034, partial η² = 0.05). After stratification by mood status we found a significant difference in adiponectin between controls, euthymic and depressive patients (F(2, 180) = 4.90, P = 0.008, partial η² = 0.05).Conclusions: This investigation confirms previous findings of an association between low adiponectin levels and depressive state in individuals with BD. Beyond its immediate effect on central nervous system function, adiponectin might interfere with pathophysiological mechanisms of BD and its somatic comorbidities via involvement in metabolic and inflammatory processes.

Branched-chain amino acids are associated with metabolic parameters in bipolar disorder

Objectives: An important aspect of bipolar disorder (BD) research is the identification of biomarkers pertaining to the somatic health state. The branched-chain essential amino acids (BCAAs), viz valine, leucine and isoleucine, have been proposed as biomarkers of an individual's health state, given their influence on protein synthesis and gluconeogenesis inhibition.Methods: BCAA levels of 141 euthymic/subsyndromal individuals with BD and 141 matched healthy controls (HC) were analysed by high-pressure lipid chromatography and correlated with clinical psychiatric, anthropometric and metabolic parameters.Results: BD and HC did not differ in valine and isoleucine, whereas leucine was significantly lower in BD. Furthermore, correlations were found between BCAAs and anthropometric and glucose metabolism data. All BCAAs correlated with lipid metabolism parameters in females. There were no associations between BCAAs and long-term clinical parameters of BD. A negative correlation was found between valine and Hamilton Depression-Scale, and Beck Depression Inventory II, in male individualsConclusions: Our results indicate the utility of BCAAs as biomarkers for the current state of health, also in BD. As BD individuals have a high risk for overweight/obesity, in association with comorbid medical conditions (e.g. cardiovascular diseases or insulin resistance), health state markers are urgently required. However, no illness-specific associations were found in this euthymic/subsyndromal BD group.

Cognitive Development in Patients with Bipolar Disorder and Metabolic Syndrome

OBJECTIVE

To describe and discuss current evidence on the relationship between cognitive performance, Bipolar Affective Disorder (BAD) and Metabolic Syndrome (MS).

METHODS

We searched for related articles in different bibliographic databases (MEDLINE, EMBASE, Scielo) and performed a narrative review of the literature with the selected articles.

RESULTS

To date, evidence has not been conclusive and the effect of MS on BD has not been widely studied, but important correlations have been observed with individual metabolic variables. It is suggested that obesity in patients with BAD is associated wotj worse performance in verbal memory, psychomotor processing speed, and sustained attention. Hypertriglyceridemia in patients with BAD appears to be associated with a lower score in executive function tasks; hypertension appears to be associated with impairment in overall cognitive function.

CONCLUSIONS

Despite the associations between MS and poor cognitive performance in patients suffering from BAD, more studies are required to precisely determine how these variables are related to each other.

Weight Gain During Treatment of Bipolar Disorder (BD)-Facts and Therapeutic Options

Bipolar disorder (BPD) is a mood disorder, which is characterized by alternating affective states, namely (hypo)mania, depression, and euthymia. Evidence is growing that BPD has indeed a biologic substrate characterized by chronic inflammation, oxidative stress, and disturbed energy metabolism. Apart from this, there is obviously a hereditary component of this disease with multi-genetic factors. Most probably a susceptibility threshold favors the outbreak of clinical disease after a cascade of stress events that remain to be elucidated in more detail. Evidence is also growing that weak points in brain energy metabolism contribute to outbreak and severity of BPD. Conventional psychopharmacologic therapy must be reassessed under the aspects of weight cycling and development of central obesity as a deterioration factor for a worse clinical course leading to early cardiovascular events in BPD subgroups.

Neurococognitive and neuroimaging correlates of obesity and components of metabolic syndrome in bipolar disorder: a systematic review

BACKGROUND

Individuals with bipolar disorder (BD) have a higher prevalence of obesity and metabolic syndrome (MetS) compared with the general population. Obesity and MetS are associated with cognitive deficits and brain imaging abnormalities in the general population. Obesity and components of MetS might potentially associate with neuroimaging and neurocognitive findings in BD.

METHODS

A literature search of studies investigating the association between obesity (and other components of MetS) and neurocognitive and neuroimaging findings in BD was conducted. In addition to a systematic review, a random-effects meta-analysis was conducted when sufficient data were available.

RESULTS

Twenty-three studies were included in the current systematic review. Overweight/obese patients were significantly associated with impaired neurocognition compared normal weight individuals with BD (d = 0.37). The most robust association between obesity and cognitive deficits in BD was observed in the cognitive subdomain of executive functions (d = 0.61). There was also evidence for a significant relationship between cognitive impairment in BD and other components of MetS including hypertension, dyslipidemia, and diabetes. Overweight/obese individuals with BD had more pronounced brain imaging abnormalities than normal weight individuals with BD.

CONCLUSIONS

Obesity and related cardiovascular risk factors significantly are associated with more severe cognitive and brain imaging abnormalities in BD. Medical co-morbidities can potentially contribute to functional decline observed in some patients throughout the course of BD.

The relationship between "Eyes Reading" ability and verbal memory in bipolar disorder

In psychiatric disorders, neurocognitive impairments are prevalent and have been associated with poor outcome. Deficits in Theory of Mind (ToM, "mentalising") have also been observed in bipolar disorder (BD); however, the literature shows inconsistent data. The aim of this study was to explore ToM performance in a well-characterized sample of euthymic individuals with BD and its relationship with neurocognitive function. One hundred sixteen euthymic patients with BD between 18 and 74 years (mean age = 42.4, SD = 13.8) and 79 healthy controls (mean age = 39.8, SD = 16.5) were investigated with an extensive neurocognitive test battery (Trail Making Test A/B, d2 Test of Attention, Stroop Color-Word Test, California Verbal Learning Test, Multiple Choice Vocabulary Test). Additionally, all participants were given the Reading the Mind in the Eyes Test (RMET) to measure affective ToM, the ability to make assumptions about other people´s feelings. Overall, "Eyes Reading" performance was not impaired in individuals with BD compared with controls. However, a significant relationship between RMET and verbal memory in BD was shown, particularly in males. Data showed worse RMET performance in patients with memory deficits compared to patients without memory deficits and controls. Due to cross-sectional data, no conclusions can be made with respect to cause and effect.

The relationship between inflammatory state and quantity of affective episodes in bipolar disorder

OBJECTIVES

Immunological/inflammatory processes have been proposed to play an important role in the pathophysiology of mood disorders, including bipolar disorder (BD). The present study aimed to examine the influence of immune activation, measured on the basis of inflammatory markers, on the course of illness, proxied by the number of affective episodes, in patients with BD.

METHODS

We investigated the relationship between high-sensitive CRP (hsCRP) and Interleukin 6 (IL-6), two inflammatory markers and characteristics of course of illness (e.g. number of affective episodes, depressive and manic symptoms) amongst a group of 190 individuals with BD.

RESULTS

Among females with BD, there was a positive correlation between levels of hsCRP and the number of manic and depressive episodes. Moreover, levels of hsCRP and IL-6 were positively correlated with current manic symptoms, as measured by Young-Mania-Rating-Scale. There were no significant correlations between levels of the foregoing inflammatory markers, and manic and depressive symptoms in male individuals with BD. Furthermore, compared to their untreated counterparts, female patients treated with lithium demonstrated higher levels of hsCRP and male patients treated with atypical antipsychotics lower levels of hsCRP, respectively.

CONCLUSIONS

Our results are suggesting that the association between inflammatory state and affective response in patients with BD may be gender-dependent. A future research would be to evaluate whether or not these gender differences can be observed in other inflammatory pathways associated with BD.

Differential Impact of Obesity on CD69 Expression in Individuals with Bipolar Disorder and Healthy Controls

Preliminary evidence suggests that premature immunosenescence is involved in bipolar disorder (BD) pathophysiology. The cellular marker CD69 is expressed in T lymphocyte surface during their activation and its expression is negatively correlated with age. The objective of this study was to assess the moderating effects of obesity on the reduction of expression of CD69, a marker of immunosenescence. Forty euthymic patients with BD type I, aged 18-65 years, were included in this study. The healthy comparison group consisted of 39 volunteers who had no current or lifetime history of mental disorders, no use of psychotropic medications, and no known family history of mood disorders or psychosis. Peripheral blood mononuclear cells from BD patients and healthy controls were collected and isolated. The cells were allowed to grow in culture and stimulated for 3 days. CD69 was marked and read in flow cytometry. We found that the lower expression of CD69 in BD patients was moderated by body mass index (BMI) in both CD4+ (RR = 0.977, 95% CI 0.960-0.995, p = 0.013) and CD8+ cells (RR = 0.972, 95% CI 0.954-0.990, p = 0.003). Our findings indicate that BMI could potentially influence the process of premature aging in BD.

Brain structural networks and connectomes: the brain-obesity interface and its impact on mental health

PURPOSE

Obesity is a complex and multifactorial disease identified as a global epidemic. Convergent evidence indicates that obesity differentially influences patients with neuropsychiatric disorders providing a basis for hypothesizing that obesity alters brain structure and function associated with the brain's propensity toward disturbances in mood and cognition. Herein, we characterize alterations in brain structures and networks among obese subjects (ie, body mass index [BMI] ≥30 kg/m²) when compared with non-obese controls.

PATIENTS AND METHODS

We obtained noninvasive diffusion tensor imaging and generalized q-sampling imaging scans of 20 obese subjects (BMI=37.9±5.2 SD) and 30 non-obese controls (BMI=22.6±3.4 SD). Graph theoretical analysis and network-based statistical analysis were performed to assess structural and functional differences between groups. We additionally assessed for correlations between diffusion indices, BMI, and anxiety and depressive symptom severity (ie, Hospital Anxiety and Depression Scale total score).

RESULTS

The diffusion indices of the posterior limb of the internal capsule, corona radiata, and superior longitudinal fasciculus were significantly lower among obese subjects when compared with controls. Moreover, obese subjects were more likely to report anxiety and depressive symptoms. There were fewer structural network connections observed in obese subjects compared with non-obese controls. Topological measures of clustering coefficient (C), local efficiency (E_local), global efficiency (E_global), and transitivity were significantly lower among obese subjects. Similarly, three sub-networks were identified to have decreased structural connectivity among frontal-temporal regions in obese subjects compared with non-obese controls.

CONCLUSION

We extend knowledge further by delineating structural interconnectivity alterations within and across brain regions that are adversely affected in individuals who are obese.

Gender differences in the association between physical activity and cognitive function in individuals with bipolar disorder

INTRODUCTION

Bipolar disorder (BD) is accompanied by a high number of comorbidities and associated with an overall increased mortality. Especially obesity, systemic inflammatory processes and cognitive deficits are highly prevalent and increase with the course of illness. Physical activity (PA) is associated with beneficial effects on somatic comorbidities such as obesity or cardiovascular disease in individuals without psychiatric disorder. Furthermore, PA might increase neurocognitive performance and reduce systemic inflammation.

OBJECTIVE

The aim of the study was to investigate the association between PA and neurocognitive function in euthymic individuals suffering from BD.

METHODS AND PARTICIPANTS

120 individuals with BD, euthymic at test time, completed the self-reported International Physical Activity Questionnaire (IPAQ) assessing PA of the past seven days and were accordingly assigned to a specific activity category (low, moderate or vigorous). Furthermore, clinical parameters were gathered and cognitive tests analysing verbal-dependent intelligence, attention, executive functioning as well as memory were administered.

RESULTS

Female individuals in the vigorous PA group performed significantly higher in most of the cognitive domains compared to females with moderate or low PA. In males, we only found a significant difference in one test for attention between moderate/vigorous and the low activity group.

CONCLUSION

Differences between PA groups in cognitive performance in female individuals with BD were obvious in almost all cognitive domains. As cognitive deficits are strongly associated with a worse course of disease and outcome, PA might offer a concomitant therapy targeting not only somatic comorbidities such as obesity and cardiovascular disease, but also neurocognition.

Inflammation: opportunities for treatment stratification among individuals diagnosed with mood disorders

Mood disorders continue to be a significant burden to those affected, resulting in significant illness-associated disability and premature mortality. In addition to mood disturbance, individuals also suffer from other transdiagnostic impairments (eg, anhedonia and cognitive impairment). Although there have been significant advancements in psychiatric treatment over the last few decades, treatment efficacy (eg, symptom remission, lack of functional recovery, and disease modification) continues to be an important limitation. Consequently, there is an urgent need to identify novel approaches capable of addressing the foregoing needs, providing the basis for the exploration of conceptual models and treatment opportunities that consider inflammation to be a key factor in mood disorder development. In part driven by metabolic comorbidities, a large proportion of individuals with mood disorders also have an imbalance in the inflammatory milieu. The aim of this review is to highlight evidence implicating inflammation in various effector systems in mood disorders, with a particular focus on the intercommunication with glutamatergic signaling, immune system signaling, as well as metabolic parameters (eg, L-methyl folate bioavailability). This article also briefly reviews novel and repurposed agents that are capable of targeting the innate immune inflammatory system and possibly correcting an abnormal immune/inflammatory milieu (eg, infliximab).

Serum levels of second-generation antipsychotics are associated with cognitive function in psychotic disorders

OBJECTIVES

Antipsychotics are effective in treating psychosis and mood episodes; however, the effect on cognition is less known. We investigated the association between serum levels of second-generation antipsychotics (SGAs) and cognitive performance in psychosis spectrum disorders in a naturalistic setting.

METHODS

A total of 495 patients with a DSM-IV Schizophrenia and Other Psychotic Disorders (SCZ, n = 373) or Bipolar Disorder (BD, n = 122) diagnosis treated with olanzapine, quetiapine, aripiprazole or risperidone were tested neuropsychologically with concurrent measurement of the serum concentration of the drug. Linear regression was used for association analyses.

RESULTS

Attention was positively associated with the olanzapine concentration (standardised beta (β) coefficient = 0.19, P = .006), and short-term verbal memory and verbal fluency were negatively associated with the quetiapine (β = -0.24, P = .004) and risperidone (β = -0.37, P = .007) concentrations respectively.

CONCLUSIONS

The present results suggest that SGA serum concentration is associated with better attention (small effect size), and worse verbal memory (small effect size) and verbal fluency (medium effect size). These findings are in line with the notion that SGAs affect aspects of cognitive function, and suggest careful dosing in patients with severe memory and executive problems.

Obesity in patients with major depression is related to bipolarity and mixed features: evidence from the BRIDGE-II-Mix study

OBJECTIVES

The Bipolar Disorders: Improving Diagnosis, Guidance and Education (BRIDGE)-II-Mix study aimed to estimate the frequency of mixed states in patients with a major depressive episode (MDE) according to different definitions. The present post-hoc analysis evaluated the association between obesity and the presence of mixed features and bipolarity.

METHODS

A total of 2811 MDE subjects were enrolled in a multicenter cross-sectional study. In 2744 patients, the body mass index (BMI) was evaluated. Psychiatric symptoms, and sociodemographic and clinical variables were collected, comparing the characteristics of MDE patients with (MDE-OB) and without (MDE-NOB) obesity.

RESULTS

Obesity (BMI ≥30) was registered in 493 patients (18%). In the MDE-OB group, 90 patients (20%) fulfilled the DSM-IV-TR criteria for bipolar disease (BD), 225 patients (50%) fulfilled the bipolarity specifier criteria, 59 patients (13%) fulfilled DSM-5 criteria for MDEs with mixed features, and 226 patients (50%) fulfilled Research-Based Diagnostic Criteria for an MDE. Older age, history of (hypo)manic switches during antidepressant treatment, the occurrence of three or more MDEs, atypical depressive features, antipsychotic treatment, female gender, depressive mixed state according to DSM-5 criteria, comorbid eating disorders, and anxiety disorders were significantly associated with the MDE-OB group. Among (hypo)manic symptoms during the current MDE, psychomotor agitation, distractibility, increased energy, and risky behaviors were the variables most frequently associated with MDE-OB group.

CONCLUSIONS

In our sample, the presence of obesity in patients with an MDE seemed to be associated with higher rates of bipolar spectrum disorders. These findings suggest that obesity in patients with an MDE could be considered as a possible marker of bipolarity.

The role of tryptophan metabolism and food craving in the relationship between obesity and bipolar disorder

BACKGROUND & AIMS

Individuals with bipolar disorder (BD) have a significantly increased risk of obesity-related conditions. The imbalance between food intake and energy expenditure is assumed to be a major risk factor for obesity in BD. This study analyzed food craving in relation to anthropometric, metabolic, and neurobiological parameters in a well-characterized cohort of euthymic individuals with BD.

METHODS

One-hundred-thirty-five patients completed the Food-Craving Inventory assessing four categories of food craving (fat, fast-food, sweets and carbohydrate craving). Additionally, clinical, metabolic and anthropometric parameters were assessed.

RESULTS

Higher levels of fat craving were observed in males, versus females, with BD. High levels of carbohydrate craving positively correlated with kynurenine and the kynurenine-to-tryptophan ratio. Higher serum nitrite and neopterin levels were related to fat craving. Parameters of fat metabolism (triglycerides, high-density lipoprotein) were associated with fat and fast-food craving. Anthropometric measures of obesity (e.g. body mass index, waist-to-hip-ratio) were not related to food craving.

CONCLUSIONS

Overweight/obese individuals with BD show an increased driving of tryptophan down the kynurenine pathways, as indicated by an increase in the serum kynurenine-to-tryptophan ratio. The driving of tryptophan down the kynurenine pathway is mediated by immune-inflammatory activity and stress. The correlation of increased kynurenine with food craving, especially carbohydrate craving, probably indicates a regulatory deficit in the maintenance of chronic inflammatory processes in obesity and BD. Food craving seems to be of clinical importance in the treatment of metabolic disturbances in BD, although not associated with anthropometric measures of obesity. Rather, food craving correlates with blood metabolic parameters and an increased activation of the kynurenine pathway, both of which are linked to higher affective symptomatology and the development of cardiovascular diseases.

Tryptophan breakdown and cognition in bipolar disorder

INTRODUCTION

It has been demonstrated that bipolar disorder (BD) is often accompanied by cognitive deficits across all subdomains including verbal memory, attention and executive functioning. Cognitive deficits are observed both during episodes of mania or depression, as well as during the euthymic phase. It has been proposed that chronic immune-mediated inflammation in the central nervous system results in alterations in neural structures that subserve cognitive function. Kynurenine is an intermediate in the inflammatory cascade and can be peripherally measured to proxy inflammatory activity. Herein, we sought to determine whether serum levels of kynurenine and/or its metabolites were associated with cognitive function in BD.

METHODS

In this investigation 68 euthymic individuals with BD according to DSM-IV completed a cognitive test battery to asses premorbid intelligence (Multiple Choice Word Test; MWT-B), verbal memory (California Verbal Learning Test; CVLT), attention (d2 Test of Attention; d2 test, Trail Making Test-A; TMT-A, Stroop word reading/Stroop color naming) and executive functioning (TMT-B, Stroop interference). In addition, fasting blood samples were taken and serum levels of kynurenine and its metabolites 3-hydroxykynurenine and kynurenic acid were analyzed. Subsequently ratios were formed from individual parameters. Patient data were compared with those of a mentally healthy control group (n=93).

RESULTS

In male participants with BD only we found a significant negative correlation between the 3-hydroxykynurenine to kynurenic acid ratio and performance on the CVLT. Additionally, the kynurenine to 3-hydroxykynurenine ratio was associated with performance on a sub-score of the CVLT. Those associations were neither present in female individuals with BD nor in the control group.

DISCUSSION

Our findings suggest that a shift towards the hydroxykynurenine arm of the kynurenine pathway may be associated with poorer memory performance due to its effects on neuronal functioning and neurogenesis in the hippocampus. Our results implicate a mechanistic role of central inflammatory processes in cognitive functions in adults with bipolar disorder.

Cognitive Impairment in Bipolar Disorder: Treatment and Prevention Strategies

Over the last decade, there has been a growing appreciation of the importance of identifying and treating cognitive impairment associated with bipolar disorder, since it persists in remission periods. Evidence indicates that neurocognitive dysfunction may significantly influence patients' psychosocial outcomes. An ever-increasing body of research seeks to achieve a better understanding of potential moderators contributing to cognitive impairment in bipolar disorder in order to develop prevention strategies and effective treatments. This review provides an overview of the available data from studies examining treatments for cognitive dysfunction in bipolar disorder as well as potential novel treatments, from both pharmacological and psychological perspectives. All these data encourage the development of further studies to find effective strategies to prevent and treat cognitive impairment associated with bipolar disorder. These efforts may ultimately lead to an improvement of psychosocial functioning in these patients.

Lower cognitive functioning as a predictor of weight gain in bipolar disorder: a 12-month study

OBJECTIVE

In cross-sectional studies, elevated body mass index (BMI) is associated with cognitive impairment in bipolar disorder (BD). We investigated the direction of this association by prospectively examining changes in BMI and cognition.

METHOD

We measured BMI and performance in six cognitive domains over 12 months in 80 adolescent and young adult BD patients and 46 healthy comparison subjects (HS). Ninety-three percent of patients received pharmacotherapy and 84% were euthymic. We used repeated-measures ancova and longitudinal mixed models to investigate whether (i) higher BMI and increasing BMI over time predicted lower subsequent cognitive functioning, and (ii) lower cognitive functioning and changes in cognition predicted increasing BMI.

RESULTS

Neither baseline BMI nor BMI change predicted lower cognitive functioning. Lower baseline scores in attention, verbal memory, working memory, and a composite measure of global cognition predicted increasing BMI in patients and HS. In patients, lower cognitive functioning remained associated with increasing BMI when clinical and treatment variables were adjusted for. Improvement in working memory predicted a smaller subsequent BMI increase in patients.

CONCLUSION

Lower cognitive functioning in specific domains predicts increasing BMI in patients with BD and healthy young adults. Targeting cognition may be important for minimizing weight gain in BD.

Increased breakdown of kynurenine towards its neurotoxic branch in bipolar disorder

Introduction

Bipolar disorder (BD) is a chronic psychiatric disease which can take most different and unpredictable courses. It is accompanied by unspecific brainstructural changes and cognitive decline. The neurobiological underpinnings of these processes are still unclear. Emerging evidence suggests that tryptophan catabolites (TRYCATs), which involve all metabolites of tryptophan towards the kynurenine (KYN) branch, are involved in the etiology as well as in the course of BD. They are proposed to be mediators of immune-inflammation and neurodegeneration. In this study we measured the levels of KYN and its main catabolites consisting of the neurotoxic hydroxykynurenine (3-HK), the more neuroprotective kynurenic acid (KYNA) and anthranilic acid (AA) and evaluated the ratios between end-products and substrates as proxies for the specific enzymatic activity (3-HK/KYN, KYNA/KYN, AA/KYN) as well as 3-HK/KYNA as a proxy for neurotoxic vs. neuroprotective end-product relation in individuals with BD compared to healthy controls (HC).

Methods

We took peripheral TRYCAT blood levels of 143 euthymic to mild depressive BD patients and 101 HC. For statistical analyses MANCOVA’s controlled for age, sex, body mass index, cardiovascular disease and smoking were performed.

Results

The levels of KYNA (F = 5,579; p <.05) were reduced in BD compared to HC. The enzymatic activity of the kynurenine-3-monooxygenase (KMO) reflected by the 3-HK/KYN ratio was increased in BD individuals compared to HC (F = 5,394; p <.05). Additionally the ratio of 3-HK/KYNA was increased in individuals with BD compared to healthy controls (F = 11,357; p <.01).

Discussion

In conclusion our findings subserve the concept of KYN -pathway alterations in the pathophysiology of BD. We present evidence of increased breakdown towards the neurotoxic branch in KYN metabolism even in a euthymic to mild depressive state in BD. From literature we know that depression and mania are accompanied by inflammatory states which should be capable to produce an even greater imbalance due to activation of key enzymes in the neurotoxic direction of KYN -conversion. These processes could finally be involved in the development of unspecific brain structural changes and cognitive deficits which are prevalent in BD. Further research should focus on state dependent changes in TRYCATs and its relation to cognition, brain structure and staging parameters.

A simple attention test in the acute phase of a major depressive episode is predictive of later functional remission

BACKGROUND

Functional recovery after a major depressive episode (MDE) requires both clinical remission and preservation of cognitive skills. As attentional deficit may persist after remission, leading to functional impairment, its role as a prognosis marker needs to be considered.

METHODS

Five hundred eight depressed outpatients (DSM-IV) were assessed at baseline for clinical symptoms (QIDS-SR), social functioning (Sheehan Disability Scale, SDS) and attention through the d2 test of attention and the trail making test, simple tests, respectively, requiring to quote or to interconnect relevant items. All patients were treated by agomelatine, and examined 6 to 8 weeks after baseline to assess clinical remission (QIDS-SR ≤ 5) and/or functional remission (SDS ≤ 6).

RESULTS

At follow up, 154 patients (31%) were in clinical and functional remission. Shorter cumulative duration of prior depression, shorter present MDE, and two parameters of the d2 test of attention were predictive of such positive outcome, the number of omission mistakes (F1) being the only one still significantly predictive (P < .05) with a multivariate approach. F1 was unchanged after remission, patients with less than 11 mistakes had a 2.27 times increased chance to reach full remission, and a dose-response relationship was observed, with a regular increase of positive outcome for less mistakes.

CONCLUSIONS

The number of omission mistakes (F1) of the d2 test of attention was a stable marker, being predictive of, and with a dose-effect for, clinical plus functional remission. It may constitute a specific marker of attentional deficit, involved in the resilience process that enables individuals to develop more adequate strategies to cope with everyday functional activities.

Metabolic syndrome and adverse clinical outcomes in patients with bipolar disorder

BACKGROUND

Metabolic syndrome (MetS) is highly prevalent among patients with bipolar disorder. MetS may cause complications in the brain, but studies investigating MetS-associated clinical psychiatric outcomes remain scant.

METHODS

We enrolled clinically stable outpatients with bipolar disorder aged 18-65 years and performed anthropometric and fasting biochemical assessments to investigate MetS prevalence. We then performed clinical assessments by using the Young Mania Rating Scale for manic symptoms, the Montgomery-Åsberg Depression Rating Scale for depressive symptoms, the Positive and Negative Symptom Scale for psychotic symptoms, the Involuntary Movement Scale for tardive dyskinesia, the Barnes Akathisia Rating Scale for akathisia, the Udvalg for Kliniske Undersogelser for general side effects, the Schedule for Assessment of Insight for insight, the Global Assessment of Functioning scale for global functioning, and the Wisconsin Card Sorting Test (WCST) for cognitive executive function.

RESULTS

In total, 143 patients were enrolled and had a MetS prevalence of 29.4%. The patients treated with atypical antipsychotics plus mood stabilizers (36.3%) and atypical antipsychotics alone (36.0%) had a significantly higher prevalence of MetS than did those treated with mood stabilizers alone (10.5%; p = 0.012). According to multivariate regression analyses adjusted for age, sex, smoking status, bipolar disorder subtype (I or II), pharmacological treatment duration, and psychiatric medication, compared with patients without MetS, those with MetS had significantly more previous hospitalizations (p = 0.036), severer tardive dyskinesia (p = 0.030), poorer insight (p = 0.036), poorer global function (p = 0.046), and more impaired executive function (conceptual level response on the WCST; p = 0.042).

CONCLUSIONS

Our results indicated that patients with comorbid bipolar disorder and MetS have more adverse clinical outcomes than those without, with more hospitalizations, severer tardive dyskinesia, poorer insight, poorer global function, and more impaired executive function. Monitoring MetS is crucial for assessing not only physical burden, but also psychiatric outcomes.

Diet Versus Exercise in Weight Loss and Maintenance: Focus on Tryptophan

An association between mood disturbance, the inability to lose or to stop gaining weight, and a craving for carbohydrates is manifested by many people who are overweight or are becoming so. In a recent study, we observed that low-calorie weight loss diet lowered not only levels of leptin but also levels of essential amino acid tryptophan (TRP) significantly. The disturbed metabolism of TRP might affect biosynthesis of serotonin and could thereby increase the susceptibility for mood disturbances and carbohydrate craving, increasing the cessation probability of weight reduction programs. Alternatively, moderate physical exercise – a potent stimulus to modulate (reduce/normalize) proinflammatory cytokines, which may affect TRP levels – could be helpful in improving mood status and preventing uncontrolled weight gain. In contrast, excessive physical exercise may induce breakdown of TRP when proinflammatory cascades together with TRP-degrading enzyme indoleamine 2,3-dioxygenase-1 are stimulated, which may lead to neuropsychiatric symptoms such as fatigue and low mood.

Impaired glucose metabolism moderates the course of illness in bipolar disorder

BACKGROUND

The longitudinal course of bipolar disorder (BD) is highly heterogeneous, and is moderated by the presence of general medical comorbidities. This study aimed to investigate the moderating effects of impaired glucose metabolism (IGM) on variables of illness course and severity in a BD population.

METHODS

Fifty-five patients with BD were evaluated. All subjects were evaluated with respect to current and past psychiatric and medical disorders, as well as lifetime use of any medication. Body mass index (BMI) and metabolic parameters were obtained. IGM was operationalized as pre-diabetes or type 2 diabetes mellitus.

RESULTS

Thirty (54.5%) individuals had IGM. After adjustment for age, gender, ethnicity, alcohol use, smoking, BMI and past and current exposure to psychotropic medications, individuals with IGM, when compared to euglycemic participants, had an earlier age of onset (RR: 0.835, p=0.024), longer illness duration (RR: 1.754, p=0.007), a higher number of previous manic/hypomanic episodes (RR: 1.483, p=0.002) and a higher ratio of manic/hypomanic to depressive episodes (RR: 1.753, p=0.028). Moreover, we observed a moderating effect of IGM on the association between number of mood episodes and other variables of illness course, with the correlation between lifetime mood episodes and frequency of episodes being significantly greater in the IGM subgroup (RR: 1.027, p=0.029). All associations observed herein remained significant after adjusting for relevant confounding factors (e.g. age, alcohol and tobacco use, exposure to psychotropic agents, BMI).

LIMITATIONS

Cross-sectional design, small sample size.

CONCLUSIONS

Comorbid IGM may be a key moderator of illness progression in BD.