Obesity and bipolar disorder: synergistic neurotoxic effects?

A meta-analysis of data-driven cognitive subgroups in bipolar disorder

The delineation of cognitive subgroups of bipolar disorder (BD) might be helpful for identifying biologically valid subtypes of this disorder. This meta-analysis identified peer-reviewed literature on studies investigating cognitive subgroups of BD with data-driven clustering methods. Relevant studies were searched in PubMed, Scopus, and Web of Science. Random-effects meta-analysis was performed using R software. A total of 14 cross-sectional studies including euthymic or mildly symptomatic patients with BD were included in the current meta-analysis. The available studies have consistently supported a 3-cluster solution. The pooled prevalence of the severe-impairment, moderate-impairment, and major good-functioning groups were 23.1 % (95%CI, 18.5 %-27.7 %), 42.5 % (95%CI, 36.3 %-48.8 %), and 33.5 % (95%CI, 25.9 %-41.1 %) respectively. Compared to healthy controls, both the severe-impairment (g=-1.40 to -1.73) and moderate-impairment groups (g=-0.59 to -0.96) had significant deficits in all six cognitive domains (verbal memory, visual memory, executive functions, working memory, attention and processing speed). The good-performance subgroup had a small increase in the performance of executive functions (g=0.23) and normal functioning in all other domains. Compared to the good-performance subgroup, the severe-impairment subgroup was characterized by more severe functional impairment, more hospital admissions, a higher percentage of type I BD and antipsychotic use. The characteristics of the moderate-impairment subgroup were lying between the other two subgroups for most of the measures. The current findings support the existence of 3 cognitive subgroups in BD including severe-impairment and moderate-impairment groups which are associated with a more severe course of illness.

Genetic associations and potential mediators between psychiatric disorders and irritable bowel syndrome: a Mendelian randomization study with mediation analysis

Objective

Potential causal associations between psychiatric disorders and irritable bowel syndrome have been demonstrated in observational studies; however, these studies are susceptible to underlying confounding and reverse causation biases. We aimed to assess the causal effects of psychiatric disorders on irritable bowel syndrome (IBS) and the potential mediators from a genetic perspective by conducting a Mendelian randomization (MR) study with mediation analysis.

Method

Genetic instruments associated with psychiatric disorders, potential mediators, and IBS were obtained from large-scale genome-wide association studies (GWAS). Three MR methods - the inverse-variance weighted (IVW) method, MR-Egger method, and weighted median method, were used to investigate causal association estimates. Heterogeneity among different genetic instrumental variables (IVs) was assessed using Q tests. Additionally, the MR-PRESSO and MR-Pleiotropy methods were used to verify horizontal pleiotropy and detect outliers that might bias the results, which were removed from further analysis. Consequently, we used MR mediation analysis to investigate potential mediators in the causal associations between psychiatric disorders and IBS.

Results

MR provided evidence of the causal effects of genetically predicted broad depression, major depressive disorder (MDD), anxiety disorder, post-traumatic stress disorder (PTSD), and schizophrenia on IBS. The results of MR mediation analysis demonstrated that the reduction in acetate levels mediated 12.6% of the effects of broad depression on IBS; insomnia mediated 16.00%, 16.20%, and 27.14% of the effects of broad depression, MDD, and PTSD on IBS, respectively; and the increase in blood β-hydroxybutyrate levels mediated 50.76% of the effects of schizophrenia on IBS.

Conclusion

Our study confirmed the brain-gut axis involvement and potential modulators in the pathophysiology of psychiatric disorder-induced IBS from a genetic perspective, and suggests potential therapeutic targets for the disrupted brain-gut axis.

Health behaviours of patients with affective disorders: a cross-sectional study

BACKGROUND

Severe mental disorders, including affective disorders (AD), are associated with high rates of physical illnesses that lead to premature patient death. Excess somatic comorbidity may be partially explained by lifestyle factors. This study aimed to investigate the health behaviours (HBs) of patients with AD in comparison to the HBs of patients with type 2 diabetes (T2D) and healthy controls (HCs) and to examine associations among HBs and sociodemographic and clinical factors, subjective quality of life and health status, and health locus of control.

METHODS

The sample consisted of 108 patients with AD, including 60 with bipolar disorder (BP) and 48 with unipolar disorder (UAD). Analyses included comparisons with a subgroup of AD individuals, patients with T2D and HCs matched in age and sex. The Health Behaviour Inventory was used to evaluate the overall levels of HBs and 4 HB categories. To identify independent determinants of health behaviours, a multivariate linear regression analysis was performed with factors identified as significant in bivariate analyses.

RESULTS

Most AD patients had a low level of HBs (40%), followed by moderate (35%) and high levels (25%), and there were no significant differences in HBs between the BP and UAD groups. Compared with the T2D and HC groups, the AD group had a significantly lower level of overall HBs and lower levels of HBs in one of the categories. Independent predictors of overall HBs were quality of life (β = 0.28, p < 0.001), age (β = 0.27, p = 0.002), and depressive symptoms (β = 0.23, p = 0.008). A total of 30% of the variance in HBs was explained.

CONCLUSIONS

These findings emphasise the need for a systematic assessment of single and multiple health behaviours to provide better care for patients with AD and reduce the potential adverse effects of an unhealthy lifestyle.

Insulin resistance disrupts white matter microstructure and amplitude of functional spontaneous activity in bipolar disorder

BACKGROUND

Bipolar disorder (BD) is linked to several structural and functional brain alterations. In addition, BD patients have a three-fold increased risk of developing insulin resistance, which is associated with neural changes and poorer BD outcomes. Therefore, we investigated the effects of insulin and two derived measures (insulin resistance and sensitivity) on white matter (WM) microstructure, resting-state (rs) functional connectivity (FC), and fractional amplitude of low-frequency fluctuation (fALFF).

METHODS

BD patients (n = 92) underwent DTI acquisition, and a subsample (n = 22) underwent rs-fMRI. Blood samples were collected to determine insulin and glucose levels. The Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) and quantitative insulin sensitivity check index (QUICKI) were computed. DTI data were analyzed via tract-based spatial statistics and threshold-free cluster enhancement. From rs-fMRI data, both ROI-to-ROI FC matrices and fALFF maps were extracted.

RESULTS

Insulin showed a widespread negative association with fractional anisotropy (FA) and a positive effect on radial diffusivity (RD) and mean diffusivity (MD). HOMA-IR exerted a significant effect on RD in the right superior longitudinal fasciculus, whereas QUICKI was positively associated with FA and negatively with RD and MD in the left superior longitudinal fasciculus, left anterior corona radiata, and forceps minor. fALFF was negatively modulated by insulin and HOMA-IR and positively associated with QUICKI in the precuneus. No significant results were found in the ROI-to-ROI analysis.

CONCLUSION

Our findings suggest that WM microstructure and functional alterations might underlie the effect of IR on BD pathophysiology, even if the causal mechanisms need to be further investigated.

Interventions targeting comorbid depression and overweight/obesity: A systematic review

BACKGROUND

Overweight/obesity and depression are highly co-occurring conditions with shared pathophysiology as well as social and economic determinants. To our knowledge, this is the first systematic review aims to comprehensively synthesize extant literature with a focus on the effectiveness of interventions targeting obesity and depression comorbidity.

METHODS

We searched databases including MEDLINE, ProQuest Central, Web of Science, PsycINFO, Cochrane Library, from inception of the databases until Nov 12, 2021. Articles were included if they reported on the effects of pharmacological, psychological or dietary interventions on comorbid depression and overweight/obesity as their primary or secondary outcome.

RESULTS

Of the 5480 identified records, 19 eligible researches comprising 15 RCTs and 4 uncontrolled longitudinal studies for 3408 participants with comorbid depression and overweight/obesity. The available literature is not sufficient to inform evidence-based treatments targeting obesity and comorbid depression contemporaneously. Notwithstanding, the combination of CBT and lifestyle intervention show efficacy targeting obesity and comorbid depression as do some nutritional supplements, antidepressants and anti-diabetic agents.

LIMITATIONS

The high heterogeneity of various interventions in the included studies may cause a lack of comparability between different studies.

CONCLUSIONS

Concurrent management of depression and overweight/obesity is suggested by available data. There is a pressing need for studies that evaluate the effectiveness in real world samples of persons experiencing multiple co-occurring chronic diseases including but not limited to depression and overweight/obesity.

Physical health in individuals with psychiatric disorders in Austria

INTRODUCTION

The association between severe psychiatric disorders and metabolic syndrome is well documented and goes along with a reduced life expectancy. The prevalence of medical comorbidities in individuals suffering from psychiatric disorders in Austria has not yet been examined; aim of this study was to analyze the prevalence of comorbid somatic disorder in individuals diagnosed with psychiatric disorders in Austria.

METHODS

Patients (n = 600) with a life-time diagnosis of mood and anxiety disorders undergoing a six-week course of intensive treatment in a psychiatric rehabilitation center were recruited. Prevalent somatic and psychological conditions, anamnestic data, medical history, blood samples, clinical and psychological tests as well as medication were examined to determine somatic and psychiatric diagnoses.

RESULTS

Metabolic disorders were highly prevalent especially in individuals diagnosed with affective disorders, respectively in bipolar disorder. Furthermore, obesity and thyroid dysfunction were found in about 40% of individuals diagnosed with bipolar disorder in the present study. Significant gender differences were found in CVD and hypertension with higher prevalence in men, while thyroid dysfunction occurred more often in women also compared to the general female population.

CONCLUSIONS

Characterizing somatic comorbidity in individuals with psychiatric disorders can stimulate research to better understand possible shared etiologic factors and has public health implications for improving models of care. This could have a positive effect on the course of mental disorders, and additionally improve social integration and life expectancy. Knowledge about sex differences should be used to further improve individualized treatment of individuals with psychiatric disorders.

The implications of hypersomnia in the context of major depression: Results from a large, international, observational study

According to the DSM-5, "reduction in the need for sleep" is the only sleep-related criteria for mixed features in depressive episodes. We aimed at studying the prevalence, clinical correlates and the role of hypersomnia in a sample of acutely depressed patients. Secondarily, we factors significantly increasing the odds of hypersomnia were studied. We conducted a post-hoc analysis of the BRIDGE-II-Mix study. Variables were compared between patients with hypersomnia (SLEEP+) and with insomnia (SLEEP-) with standard bivariate tests. A stepwise backward logistic regression model was performed with SLEEP+ as dependent variable. A total of 2514 subjects were dichotomized into SLEEP+ (n = 423, 16.8%) and SLEEP- (n = 2091, 83.2%). SLEEP+ had significant higher rates of obese BMI (p < 0.001), BD diagnosis (p = 0.027), severe BD (p < 0.001), lifetime suicide attempts (p < 0.001), lower age at first depression (p = 0.004) than SLEEP-. Also, SLEEP+ had significantly poorer response to antidepressants (AD) such as (hypo)manic switches, AD resistance, affective lability, or irritability (all 0<0.005). Moreover, SLEEP+ had significantly higher rates of mixed-state specifiers than SLEEP- (all 0 < 0.006). A significant contribution to hypersomnia in our regression model was driven by metabolic-related features, such as "current bulimia" (OR = 4.21) and "overweight/obese BMI (OR = 1.42)". Globally, hypersomnia is associated with poor outcome in acute depression. Hypersomnia is strongly associated with mixed features and bipolarity. Metabolic aspects could influence the expression of hypersomnia, worsening the overall clinical outcome. Along with commonly used screening tools, detection of hypersomnia has potential, costless discriminative validity in the differential diagnosis unipolar and bipolar depression.

Comprehensive identification of pleiotropic loci for body fat distribution using the NHGRI-EBI Catalog of published genome-wide association studies

We conducted a hypothesis-free cross-trait analysis for waist-to-hip ratio adjusted for body mass index (WHR_adjBMI ) loci derived through genome-wide association studies (GWAS). Summary statistics from published GWAS were used to capture all WHR_adjBMI single-nucleotide polymorphisms (SNPs), and their proxy SNPs were identified. These SNPs were used to extract cross-trait associations between WHR_adjBMI SNPs and other traits through the NHGRI-EBI GWAS Catalog. Pathway analysis was conducted for pleiotropic WHR_adjBMI SNPs. We found 160 WHR_adjBMI SNPs and 3675 proxy SNPs. Cross-trait analysis identified 239 associations, of which 100 were for obesity traits. The remaining 139 associations were filtered down to 101 unique linkage disequilibrium block associations, which were grouped into 13 categories: lipids, red blood cell traits, white blood cell counts, inflammatory markers and autoimmune diseases, type 2 diabetes-related traits, adiponectin, cancers, blood pressure, height, neuropsychiatric disorders, electrocardiography changes, urea measurement, and others. The highest number of cross-trait associations were found for triglycerides (n = 10), high-density lipoprotein cholesterol (n = 9), and reticulocyte counts (n = 8). Pathway analysis for WHR_adjBMI pleiotropic SNPs found immune function pathways as the top canonical pathways. Results from our original methodology indicate a novel genetic association between WHR_adjBMI and reticulocyte counts and highlight the pleiotropy between abdominal obesity, immune pathways, and other traits.

Leptin and adiponectin levels in major depressive disorder: A systematic review and meta-analysis

OBJECTIVES

To explore differences in adipokine levels (i.e., leptin and adiponectin levels) between adults with Major Depressive Disorder (MDD) and healthy controls (HC), and to discuss the possible role of adipokine regulation in the development and progression of MDD.

METHODS

A systematic review and meta-analysis were conducted based on the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. A systematic search was conducted for all English and Chinese peer-reviewed articles from inception to November 2017. A random effects model was used to calculate the standardized mean difference (SMD) of leptin and/or adiponectin levels in subjects diagnosed with MDD versus HC within a 95% confidence interval (CI).

RESULTS

Thirty-three studies were included in this meta-analysis. In total, 4,372 (52.3%) subjects with MDD and 3,984 (47.7%) HC were compared. We identified significant lower adiponectin levels in MDD compared to HC with a small effect size (ES) (SMD = -0.25; 95% CI: -0.48, -0.02; P < 0.001). However, no significant difference was observed in leptin levels between MDD subjects and HC (SMD = 0.13; 95% CI: -0.06, 0.31; P = 0.170). The heterogeneity in the results of our meta-analysis could not be completely explained by dividing subjects into subgroups. Results from subgroup analyses suggested that studies involving samples with BMI ≥ 25 had lower adiponectin levels in subjects with MDD compared to HC, and older age samples (i.e., age ≥ 40) with BMI ≥ 25 had both higher leptin levels and lower adiponectin levels in MDD subjects as compared to HC.

LIMITATIONS

The heterogeneity of included studies, small sample sizes, and potential publication bias were significant limitations.

CONCLUSIONS

The current systematic review and meta-analysis indicated that lower adiponectin levels may be associated with MDD. Moreover, the results suggest that males expressing lower adiponectin and leptin levels have an increased likelihood of developing MDD. Future studies should aim to investigate the manifestation of depressive phenotypes in older, obese populations with altered metabolic profiles resulting from adipokine dysregulation. The review has been registered with PROSPERO (registration number CRD42018082733).

Bipolar disorder and obsessive compulsive disorder: The comorbidity does not further impair the neurocognitive profile

BACKGROUND

The comorbidity of bipolar disorder (BD) and obsessive-compulsive disorder (OCD) has been widely described. Several studies have investigated the cognitive profiles of BD and OCD patients, but studies that compare BD, BD-OCD, and OCD patients in neuropsychological domains do not exist. The purpose of this study was to compare set-shifting, decision making, and central coherence among BD, BD-OCD, and OCD patients.

METHODS

A battery of neuropsychological tests was administered to 68 patients (22 BD, 26 BD-OCD, 20 OCD). The Young Mania Rating Scale and Hamilton Depression Rating Scale were used to evaluate manic and depressive symptoms, and OCD severity was assessed with the Yale Brown Obsessive Compulsive Scale.

RESULTS

No significant differences emerged in decision-making and cognitive flexibility, whereas BD patients had lower scores in the Accuracy Index on Rey-Osterrieth Complex Figure Test and poor response speed on Hayling Sentence Completion Test Part A than OCD patients.

LIMITATIONS

The small sample size with different BD patients, the cross-sectional design, and the study clinical nature.

CONCLUSIONS

The most striking result is that, contrary to our hypothesis, comorbidity does not further impair the neurocognitive profile. The clinical relevance of our work could be a shift from the current cognitive rehabilitation model focusing on individualized pathways towards a new overlapping model for all three patient groups. This could make the cognitive rehabilitation faster and less costly. Notwithstanding, these disorders do not only need cognitive training but also various psycho-educative approaches and treatment according to their different clinical profile.

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.

Food addiction: Prevalence, psychopathological correlates and associations with quality of life in a large sample

OBJECTIVE

To determine the prevalence of food addiction in a large Brazilian non-clinical sample. Sociodemographic and psychopathological correlates of food addiction as well as associations with quality (QoL) domains were also investigated.

METHODS

This cross-sectional study obtained data from a Brazilian anonymous web-based research platform (N = 7639; 71.3% females). Participants provided sociodemographic data and completed the modified Yale Food Addiction Scale 2.0, PHQ-9, hypomania checklist (HCL-32), Fagerström Test for Nicotine Dependence, AUDIT, modified Skin picking-Stanford questionnaire, Minnesota impulsive disorders interview, Symptom Checklist-90-Revised inventory (SCL-90R), early trauma inventory self report-short form, and the WHO Quality of Life instrument-Abbreviated version (WHOQOL-Bref). Associations were adjusted to potential confounders through multivariable models.

RESULTS

The prevalence of food addiction was 4.32% (95%CI: 3.89-4.80%), and was more common among females. Food addiction was associated with a positive screen for a major depressive episode (OR = 4.41; 95%CI: 3.46-5.62), bipolar spectrum disorder (OR = 1.98; 95%CI: 1.43-2.75), and skin picking disorder (OR = 2.02; 95%CI: 1.31-3.09). Food addiction was also independently associated with exposure to early life psychological and sexual abuse (P = 0.008) as well as with reduced physical, psychological, social, and environment QoL (all P < 0.001).

CONCLUSIONS

Food addiction may be common in low and middle-income countries, though possibly less prevalent than in the US. Food addiction was associated with co-occurring mood disorders and skin picking disorder as well as with early life psychological and sexual abuse. Finally, food addiction was independently associated with broad reductions in QoL. Public health efforts towards the early recognition and management of food addiction are warranted.

Shared metabolic and immune-inflammatory, oxidative and nitrosative stress pathways in the metabolic syndrome and mood disorders

This review examines the shared immune-inflammatory, oxidative and nitrosative stress (IO&NS) and metabolic pathways underpinning metabolic syndrome (MetS), bipolar disorder (BD) and major depressive disorder (MDD). Shared pathways in both MetS and mood disorders are low grade inflammation, including increased levels of pro-inflammatory cytokines and acute phase proteins, increased lipid peroxidation with formation of malondialdehyde and oxidized low density lipoprotein cholesterol (LDL-c), hypernitrosylation, lowered levels of antioxidants, most importantly zinc and paraoxonase (PON1), increased bacterial translocation (leaky gut), increased atherogenic index of plasma and Castelli risk indices; and reduced levels of high-density lipoprotein (HDL-c) cholesterol. Insulin resistance is probably not a major factor associated with mood disorders. Given the high levels of IO&NS and metabolic dysregulation in BD and MDD and the high comorbidity with the atherogenic components of the MetS, mood disorders should be viewed as systemic neuro-IO&NS-metabolic disorders. The IO&NS-metabolic biomarkers may have prognostic value and may contribute to the development of novel treatments targeting neuro-immune, neuro-oxidative and neuro-nitrosative pathways.

Physical exercise ameliorates mood disorder-like behavior on high fat diet-induced obesity in mice

Obesity is associated with mood disorders such as depression and anxiety. The aim of this study was to investigate whether treadmill exercise had any benefits on mood disorder by high fat diet (HFD) induced obesity. Mice were randomly divided into four groups: control, control and exercise, high fat diet (HFD), and HFD and exercise. Obesity was induced by a 20-week HFD (60%). In the exercise groups, exercise was performed 6 times a week for 12 weeks, with the exercise duration and intensity gradually increasing at 4-week intervals. Mice were tested in tail suspension and elevated plus maze tasks in order to verify the mood disorder like behavior such as depression and anxiety on obesity. In the present study, the number of 5-HT- and TPH-positive cells, and expression of 5-HT_1A and 5-HTT protein decreased in dorsal raphe, and depression and anxiety like behavior increased in HFD group compared with the CON group. In contrast, treadmill exercise ameliorated mood disorder like behavior by HFD induced obesity and enhanced expression of the serotonergic system in the dorsal raphe. We concluded that exercise increases the capacity of the serotonergic system in the dorsal raphe, which improves the mood disorders associated with HFD-induced obesity.

Adverse effects of obesity on cognitive functions in individuals at ultra high risk for bipolar disorder: Results from the global mood and brain science initiative

BACKGROUND

The burden of illness associated with bipolar disorder (BD) warrants early pre-emption/prevention. Prediction models limited to psychiatric phenomenology have insufficient predictive power. Herein, we aimed to evaluate whether the presence of overweight/obesity is associated with greater cognitive decline in individuals at high risk (HR) or ultra high risk (UHR) for BD.

METHODS

We conducted a retrospective analysis to investigate the moderational role of body mass index (BMI) on measures of cognitive function. Subjects between the ages of 8 and 28 years with a positive family history of BD were compared to age-matched controls with a negative family history of BD. Subjects with at least one biological parent with bipolar I/II disorder were further stratified into UHR or HR status by the presence or absence, respectively, of subthreshold hypomanic, major depressive, attenuated psychotic, and/or attention-deficit/hyperactivity disorder symptoms.

RESULTS

A total of 36 individuals at HR for BD, 33 individuals at UHR for BD, and 48 age-matched controls were included in the analysis. Higher BMI was significantly associated with lower performance on measures of processing speed (i.e. Brief Assessment of Cognition in Schizophrenia-symbol coding: r=-.186, P=.047) and attention/vigilance (i.e. Continuous Performance Test-Identical Pairs: r=-.257, P=.006). There were trends for negative correlations between BMI and measures of working memory (i.e. Wechsler Memory Scale-III Spatial Span: r=-0.177, P=.059) and overall cognitive function (i.e. Measurement and Treatment Research to Improve Cognition in Schizophrenia composite score: r=-.157, P=.097). Negative associations between BMI and cognitive performance were significantly stronger in the UHR group than in the HR group, when compared to controls.

CONCLUSIONS

Individuals at varying degrees of risk for BD exhibit greater cognitive impairment as a function of co-existing overweight/obesity. Prediction models for BD may be substantively informed by including information related to overweight/obesity and, perhaps, other general medical conditions that share pathology with BD. Our findings herein, as well as the salutary effects of bariatric surgery on measures of cognitive function in obese populations, provide the rationale for hypothesizing that mitigating excess weight in individuals at elevated risk for BD may forestall or prevent declaration of illness.

Systematic assessment of environmental risk factors for bipolar disorder: an umbrella review of systematic reviews and meta-analyses

OBJECTIVES

The pathophysiology of bipolar disorder is likely to involve both genetic and environmental risk factors. In our study, we aimed to perform a systematic search of environmental risk factors for BD. In addition, we assessed possible hints of bias in this literature, and identified risk factors supported by high epidemiological credibility.

METHODS

We searched the Pubmed/MEDLINE, EMBASE and PsycInfo databases up to 7 October 2016 to identify systematic reviews and meta-analyses of observational studies that assessed associations between putative environmental risk factors and BD. For each meta-analysis, we estimated its summary effect size by means of both random- and fixed-effects models, 95% confidence intervals (CIs), the 95% prediction interval, and heterogeneity. Evidence of small-study effects and excess of significance bias was also assessed.

RESULTS

Sixteen publications met the inclusion criteria (seven meta-analyses and nine qualitative systematic reviews). Fifty-one unique environmental risk factors for BD were evaluated. Six meta-analyses investigated associations with a risk factor for BD. Only irritable bowel syndrome (IBS) emerged as a risk factor for BD supported by convincing evidence (k=6; odds ratio [OR]=2.48; 95% CI=2.35-2.61; P<.001), and childhood adversity was supported by highly suggestive evidence. Asthma and obesity were risk factors for BD supported by suggestive evidence, and seropositivity to Toxoplasma gondii and a history of head injury were supported by weak evidence.

CONCLUSIONS

Notwithstanding that several environmental risk factors for BD were identified, few meta-analyses of observational studies were available. Therefore, further well-designed and adequately powered studies are necessary to map the environmental risk factors for BD.

A cluster analytic approach to identifying predictors and moderators of psychosocial treatment for bipolar depression: Results from STEP-BD

BACKGROUND

We sought to address how predictors and moderators of psychotherapy for bipolar depression - identified individually in prior analyses - can inform the development of a metric for prospectively classifying treatment outcome in intensive psychotherapy (IP) versus collaborative care (CC) adjunctive to pharmacotherapy in the Systematic Treatment Enhancement Program (STEP-BD) study.

METHODS

We conducted post-hoc analyses on 135 STEP-BD participants using cluster analysis to identify subsets of participants with similar clinical profiles and investigated this combined metric as a moderator and predictor of response to IP. We used agglomerative hierarchical cluster analyses and k-means clustering to determine the content of the clinical profiles. Logistic regression and Cox proportional hazard models were used to evaluate whether the resulting clusters predicted or moderated likelihood of recovery or time until recovery.

RESULTS

The cluster analysis yielded a two-cluster solution: 1) "less-recurrent/severe" and 2) "chronic/recurrent." Rates of recovery in IP were similar for less-recurrent/severe and chronic/recurrent participants. Less-recurrent/severe patients were more likely than chronic/recurrent patients to achieve recovery in CC (p=.040, OR=4.56). IP yielded a faster recovery for chronic/recurrent participants, whereas CC led to recovery sooner in the less-recurrent/severe cluster (p=.034, OR=2.62).

LIMITATIONS

Cluster analyses require list-wise deletion of cases with missing data so we were unable to conduct analyses on all STEP-BD participants.

CONCLUSIONS

A well-powered, parametric approach can distinguish patients based on illness history and provide clinicians with symptom profiles of patients that confer differential prognosis in CC vs. IP.

Body mass index and psychiatric disorders: a Mendelian randomization study

Obesity is a highly prevalent risk factor for cardiometabolic diseases. Observational studies suggest that obesity is associated with psychiatric traits, but causal inference from such studies has several limitations. We used two-sample Mendelian randomization methods (inverse variance weighting, weighted median and MR-Egger regression) to evaluate the association of body mass index (BMI) with three psychiatric traits using data from the Genetic Investigation of Anthropometric Traits and Psychiatric Genomics consortia. Causal odds ratio estimates per 1-standard deviation increment in BMI ranged from 0.88 (95% CI: 0.62; 1.25) to 1.23 (95% CI: 0.65; 2.31) for bipolar disorder; 0.93 (0.78; 1.11) to 1.41 (0.87; 2.27) for schizophrenia; and 1.15 (95% CI: 0.92; 1.44) to 1.40 (95% CI: 1.03; 1.90) for major depressive disorder. Analyses removing potentially influential SNPs suggested that the effect estimates for depression might be underestimated. Our findings do not support the notion that higher BMI increases risk of bipolar disorder and schizophrenia. Although the point estimates for depression were consistent in all sensitivity analyses, the overall statistical evidence was weak. However, the fact that SNP-depression associations were estimated in relatively small samples reduced power to detect causal effects. This should be re-addressed when SNP-depression associations from larger studies become available.

Obesity, but not metabolic syndrome, negatively affects outcome in bipolar disorder

OBJECTIVE

Examine the effects of obesity and metabolic syndrome on outcome in bipolar disorder.

METHOD

The Comparative Effectiveness of a Second Generation Antipsychotic Mood Stabilizer and a Classic Mood Stabilizer for Bipolar Disorder (Bipolar CHOICE) study randomized 482 participants with bipolar disorder in a 6-month trial comparing lithium- and quetiapine-based treatment. Baseline variables were compared between groups with and without obesity, with and without abdominal obesity, and with and without metabolic syndrome respectively. The effects of baseline obesity, abdominal obesity, and metabolic syndrome on outcomes were examined using mixed effects linear regression models.

RESULTS

At baseline, 44.4% of participants had obesity, 48.0% had abdominal obesity, and 27.3% had metabolic syndrome; neither obesity, nor abdominal obesity, nor metabolic syndrome were associated with increased global severity, mood symptoms, or suicidality, or with poorer functioning or life satisfaction. Treatment groups did not differ on prevalence of obesity, abdominal obesity, or metabolic syndrome. By contrast, among the entire cohort, obesity was associated with less global improvement and less improvement in total mood and depressive symptoms, suicidality, functioning, and life satisfaction after 6 months of treatment. Abdominal obesity was associated with similar findings. Metabolic syndrome had no effect on outcome.

CONCLUSION

Obesity and abdominal obesity, but not metabolic syndrome, were associated with less improvement after 6 months of lithium- or quetiapine-based treatment.

Inflammation as a neurobiological substrate of cognitive impairment in bipolar disorder: Evidence, pathophysiology and treatment implications

BACKGROUND

Bipolar disorder (BD) has been associated with cognitive impairment during depressed, manic and euthymic periods. Inflammation has been shown to be involved in the pathophysiology of BD and cognitive impairment.

METHODS

For this systematic review, the MEDLINE/PubMed, Embase, Google Scholar and ClinicalTrials.gov databases were searched for relevant articles assessing the association between cognitive function and inflammatory markers in BD subjects. A discussion of potential mechanisms and therapeutic implications is also included to provide further context to the subject matter.

RESULTS

Eight studies, including a total of 555 BD subjects, assessing the association between cognitive function and inflammatory markers were identified. Cognitive dysfunction was associated with elevated levels of pro-inflammatory markers YKL40, IL-6, sCD40L, IL-1Ra, hsCRP and TNF-α. Mechanistically, elevation in inflammatory cytokines alters monoamine levels leading to cognitive and affective dysfunction. Neuro-inflammation, manifesting as microglial activation, leads to increased oxidative stress, pathologic synaptic pruning and impaired neuroplasticity in key brain regions sub-serving mood and cognition. Immune dysfunction also activates the hypothalamic-pituitary-adrenal (HPA) axis leading to hypercortisolemia and metabolic dysfunction, further promoting neuronal dysfunction. Anti-inflammatory agents are therefore currently being investigated in the treatment of BD and appear to exert an antidepressant effect; however, cognitive outcomes have yet to be reported.

CONCLUSION

Several studies suggest that immune dysfunction is associated with cognitive impairment in BD. Several neurobiological pathways have been identified whereby immune dysfunction may promote cognitive impairment in BD. Future investigations of anti-inflammatory agents targeting cognitive function as a treatment outcome are merited.

Treating to target in major depressive disorder: response to remission to functional recovery

Treating to target in chronic diseases [e.g. Major Depressive Disorder (MDD)] fosters precision, consistency, and appropriateness of treatment selection and sequencing. Therapeutic target definitions/endpoints in MDD should satisfy patient-, provider-, and societal expectations. Functional recovery in depression and return to both physical and mental health are the overarching therapeutic objectives. Treating to target in MDD implies multidimensional symptomatic remission, with a particular emphasis on cognitive function and aspects of positive mental health. Several atypical antipsychotic agents (i.e. brexpiprazole, aripiprazole, quetiapine) are FDA-approved as augmentation agents in MDD. Vortioxetine, duloxetine, and psychostimulants have evidence of independent, direct, and robust effects on cognitive function in MDD. Vortioxetine is the only agent that demonstrates efficacy across multiple cognitive domains in MDD associated with functional recovery. Measurement-based care, health information technology/systems, and integrated care models (e.g. medical homes) provide requisite tools and health environments for optimal health outcomes in MDD. Achieving remission in MDD does not equate to health. Return to positive mental health as well as full functioning provide the impetus to pivot away from traditional provider-defined outcomes toward an inclusive perspective involving patient- and society-defined outcomes (i.e. optimization of human capital). As in other chronic diseases, treating to target (e.g. cognitive function) further increases the probability of achieving optimal health outcomes.

Is bipolar disorder associated with accelerating aging? A meta-analysis of telomere length studies

BACKGROUND

Bipolar disorder (BD) is associated with a reduced life expectancy compared to the general population mainly due to a high prevalence of comorbid somatic illnesses. A model of accelerated aging has been proposed as a potential explanation to these epidemiological findings. Nevertheless, studies measuring telomere length (TL) in patients with BD compared to healthy controls have provided mixed results.

OBJECTIVE

To compare TL between BD patients and healthy controls, and to search for potential modeP<rators for observed differences.

METHODS

We performed a systematic review and meta-analysis of original studies comparing TL in patients with BD vs. healthy controls published up to February 24th, 2015 in main electronic databases. Heterogeneity was explored through meta-regression and subgroup analysis.

RESULTS

Seven studies met inclusion criteria (N=1115). There was no difference in TL between participants with BD and healthy controls (Hedges's g=-0.012; 95% CI=-0.418 to 0.393, P=0.952). There was no evidence for publication bias. Heterogeneity was high (I(2)=89.65%). In meta-regression analyses, the percentage of females in healthy control samples (P=0.04) and the methodological quality of included studies (P<0.001) emerged as significant moderators, while subgroup analyses suggest that the type of assay employed to measure TL and age- and gender-matching of BD and HC participants may contribute to heterogeneity.

CONCLUSIONS

Telomere length does not differ between participants with BD vs. healthy controls; this finding does not support the view of BD as an illness associated with accelerated cellular aging. However, more studies controlling for potential confounders are necessary.

Atypical features in depression: Association with obesity and bipolar disorder

OBJECTIVES

Depression with atypical features amounts to a significant proportion of depressed patients. Studies have shown its association with bipolarity and, recently, with obesity. In this study, we investigated atypical features of depression in relation to overweight/obesity in three diagnostic categories: unipolar depression, bipolar depression and dysthymia.

METHODS

Out of 512 depressed patients screened, we recruited 182 research subjects, consisting of 91 pairs, matched by age, gender and diagnosis, in which one member of the pair was within the normal weight range (BMI≤25) and the other was either overweight or obese (BMI>25). There were 35 pairs with unipolar depression, 27 with bipolar depression and 29 with dysthymia. Symptoms of atypical depression, such as increased appetite, hypersomnia, leaden paralysis, longstanding pattern of interpersonal rejection sensitivity, and, a significant weight gain in the past 3 months, were assessed.

RESULTS

All the symptoms of atypical depression were significantly more pronounced in those depressed patients with a BMI>25, compared with depressed subjects with a normal weight. Except for hypersomnia, these symptoms scored significantly higher in women compared to men. Among the diagnostic categories, symptoms of atypical depression were significantly higher in patients with bipolar disorder compared with both major depressive disorder and dysthymia.

LIMITATIONS

The preponderance of women, the assessment of atypical depression by adaptation of the DSM criteria, entirely Polish population, specificity of selection criteria.

CONCLUSIONS

The results demonstrated a higher intensity of atypical depression's symptoms in overweight/obese depressed patients. They also confirm the association between obesity and bipolarity.

Are medical comorbid conditions of bipolar disorder due to immune dysfunction?

OBJECTIVE

Epidemiological data have shown a clear association between bipolar disorder (BD) and medical comorbidities. The aim of this article was to assess the evidence of immune dysfunction as a key mediator of this observed association.

METHOD

For this narrative clinical overview, the MEDLINE/PubMed, EMBASE, Google Scholar, and ClinicalTrials.gov databases were searched for relevant articles.

RESULTS

Bipolar disorder has been shown to have an increased prevalence in patients with autoimmune disorders, cardiovascular disease, and metabolic dysfunction. Further, an elevation in proinflammatory cytokines in BD has been repeatedly demonstrated. Several mechanisms have been proposed to explain the effect of immune dysfunction on mood and cognition. Anti-inflammatory agents including TNF-α inhibitors, non-steroidal anti-inflammatory drugs (NSAIDs), minocycline and omega-3 polyunsaturated fatty acids (O3PUFA) are being investigated for their use as novel treatment of BD in patients with immune dysfunction.

CONCLUSION

Immune dysfunction appears to be an important mediator of the association observed between BD and medical comorbidities. It therefore serves as a potential novel target for treatment of BD. Further, the observed bidirectional interaction merits screening for psychiatric disorders in patients with immune dysfunction and vice versa to allow for early detection and treatment of this at risk population.

Comparison of pro-inflammatory cytokines among patients with bipolar disorder and unipolar depression and normal controls

OBJECTIVE

Research evidence has shown that bipolar disorder (BD) and unipolar depression (UD) are both related to inflammatory dysregulation, but few studies have compared the levels of cytokines between these two disorders.

METHODS

Study subjects were age- and gender-matched outpatients with BD or UD and normal controls (NC). Severities of depression and mania symptoms were assessed with the Montgomery-Åsberg Depression Rating Scale (MADRS) and the Young Mania Rating Scale (YMRS). Pro-inflammatory cytokines, including soluble interleukin-6 receptor (sIL-6R), soluble interleukin-2 receptor (sIL-2R), C-reactive protein (CRP), soluble tumor necrosis factor receptor type 1 (sTNF-R1), soluble p-selectin receptor (sP-selectin), and monocyte chemotactic protein-1 (MCP-1), were assessed in all subjects by enzyme-linked immunosorbent assays.

RESULTS

In all, 130 patients with BD, 149 patients with UD, and 130 NC were enrolled in the study; 67.6% were female and the average age was mean ± standard deviation (SD) 43.5 ± 11.8 years. The BD group had a significantly higher smoking rate, more medical comorbidity, higher body mass index (BMI), and higher levels of sIL-2R, sIL-6R, CRP, sTNF-R1, and MCP-1 (all p < 0.01) than the UD and NC groups. When the remitted patients with BD (YMRS scores ≤ 12) were compared with the patients with UD, controlling for age, MADRS score, smoking, medical comorbidity, and BMI in the regression model, the results showed that the BD group had significantly higher levels of sIL-6R (p < 0.001), CRP (p = 0.045), sTNF-R1 (p = 0.036), and MCP-1 (p = 0.001) than the UD group.

CONCLUSIONS

Higher levels of sIL-6R, CRP, sTNF-R1, and MCP-1 were noted in BD than in UD. These results may suggest a more severe inflammatory dysregulation in BD. Further studies are required to investigate whether these cytokines could be biomarkers for affective disorders.

Castelli risk indexes 1 and 2 are higher in major depression but other characteristics of the metabolic syndrome are not specific to mood disorders

AIMS

This study examined whether Castelli risk indexes 1 (total/high-density lipoprotein (HDL) cholesterol) and 2 (low density lipoprotein (LDL)/HDL cholesterol) and other shared metabolic disorders might underpin the pathophysiology of the metabolic syndrome, major depression or bipolar disorder.

MAIN METHODS

This cross-sectional study examined 92 major depressed, 49 bipolar depressed and 201 normal controls in whom the Castelli risk indexes 1 and 2 and key characteristics of the metabolic syndrome, i.e. waist/hip circumference, body mass index (BMI), systolic/diastolic blood pressure, total cholesterol, low-density lipoprotein (LDL) and HDL cholesterol, triglycerides, insulin, glucose, hemoglobin A1c (HbA1c) and homocysteine were assessed.

KEY FINDINGS

Castelli risk indexes 1 and 2 were significantly higher in major depressed patients than in bipolar disorder patients and controls. There were no significant differences in waist or hip circumference, total and LDL cholesterol, triglycerides, plasma glucose, insulin, homocysteine and HbA1c between depression and bipolar patients and controls. Bipolar patients had a significantly higher BMI than major depressed patients and normal controls.

SIGNIFICANCE

Major depression is accompanied by increased Castelli risk indexes 1 and 2, which may be risk factors for cardiovascular disease. Other key characteristics of the metabolic syndrome, either metabolic biomarkers or central obesity, are not necessarily specific to major depression or bipolar disorder.