The neurobiology of bipolar disorder

Incidence of psychiatric disorders after total knee or hip arthroplasty by anesthesia type: A nationwide cohort study

BACKGROUND

Evidence is lacking of an association between anesthetic choice and the risk of psychiatric disorders. Therefore, this study aimed to examine the impact of regional anesthesia (R/A) versus general anesthesia (G/A) on the occurrence of psychiatric disorders in patients undergoing total knee arthroplasty (TKA) or total hip arthroplasty (THA).

METHODS

Data for this population-based cohort study were sourced from the National Health Insurance Service of South Korea. The study included adult patients who underwent TKA or THA between January 1, 2016, and December 31, 2021. The endpoint was the diagnosis of postoperative psychiatric disorders within 1 year postoperative.

RESULTS

This study included 411,967 patients who underwent THA or TKA. Among them, 290,476 (70.5 %) underwent THA or TKA under R/A (R/A group), while 121,491 (29.5 %) underwent THA or TKA under G/A (G/A group). In multivariate logistic regression, the R/A group had an 8 % lower incidence of postoperative psychiatric disorders (odds ratio [OR], 0.92; 95 % confidence interval [CI], 0.90-0.94; P < 0.001) than the G/A group. Specifically, a lower incidence of postoperative psychiatric disorder for depression (OR, 0.89; 95 % CI, 0.86-0.92; P < 0.001), bipolar disorder (OR, 0.88; 95 % CI, 0.83-0.94; P < 0.001), anxiety disorder (OR, 0.95; 95 % CI, 0.92-0.98; P = 0.001), and insomnia disorder (OR, 0.95; 95 % CI, 0.80-1.11; P = 0.496) was observed in the R/A versus G/A group.

CONCLUSIONS

Among these South Korean patients who underwent TKA or THA, the R/A group had a lower incidence of postoperative psychiatric disorders than the G/A group.

SNP Data Science for Classification of Bipolar Disorder I and Bipolar Disorder II

Bipolar disorder I (BD-I) and bipolar disorder II (BD-II) have specific characteristics and clear diagnostic criteria, but quite different treatment guidelines. In clinical practice, BD-II is commonly mistaken as a mild form of BD-I. This study uses data science technique to identify the important Single Nucleotide Polymorphisms (SNPs) significantly affecting the classifications of BD-I and BD-II, and develops a set of complementary diagnostic classifiers to enhance the diagnostic process. Screening assessments and SNP genotypes of 316 Han Chinese were performed with the Affymetrix Axiom Genome-Wide TWB Array Plate. The results show that the classifier constructed by 23 SNPs reached the area under curve of ROC (AUC) level of 0.939, while the classifier constructed by 42 SNPs reached the AUC level of 0.9574, which is a mere addition of 1.84 percent. The accuracy rate of classification increased by 3.46 percent. This study also uses Gene Ontology (GO) and Pathway to conduct a functional analysis and identify significant items, including calcium ion binding, GABA-A receptor activity, Rap1 signaling pathway, ECM proteoglycans, IL12-mediated signaling events, Nicotine addiction), and PI3K-Akt signaling pathway. The study can address time-consuming SNPs identification and also quantify the effect of SNP-SNP interactions.

Resolvin D1 as a novel anti-inflammatory marker in manic, depressive and euthymic states of bipolar disorder

Background: Resolvin D1 (RvD1) is a soluble mediator, which is the metabolite of docosahexaenoic acid (DHA), an omega-3 fatty acid. It is thought that RvD1 may contribute to the etiology of bipolar disorder (BD) because of its anti-inflammatory and antidepressant effect. In this study, it was aimed to compare the serum RvD1 levels of patients with BD diagnosed manic-depressive-euthymic episodes with those of healthy subjects. The secondary objective of this study is to investigate the relationship between RvD1 measures and inflammatory markers.Methods: We included 121 male patients with BD type I, 44 in a mania, 35 in depression and 42 in euthymic state, and 41 healthy controls. Serum RvD1 levels and inflammation indicators (CRP, neutrophil, leukocyte, and albumin) were measured.Results: When the RvD1 values of patients were compared, the median (interquartile range) RvD1 value was 11.2 (5.2) for manic patients, 11.2 (6.6) for depressive patients, 9.6 (5.6) for euthymic patients and 8.4 (7.7) for the control group. There were statistically significant differences between the groups in terms of RvD1 values (p < .001). After adjustment for age and current state with ANCOVA, there were statistically significant differences between manic vs. control groups and depression vs. control groups (p < .001, p=.047). Also mean CRP measures (p=.029) and neutrophil counts (p=.009) were significantly correlated with log transformed RvD1 levels.Conclusions: Our results of increased anti-inflammatory RvD1 during manic and depressive states suggest RvD1 may serve as a delayed resolvent possibly improving inflammatory imbalance. Further research is needed to confirm our findings.

Evaluation of Neurotransmitter Alterations in Four Distinct Brain Regions After Rapid Eye Movement Sleep Deprivation (REMSD) Induced Mania-Like Behaviour in Swiss Albino Mice

A number of neurotransmitter systems have been implicated in contributing to the pathology of mood disorders, including those of dopamine (DA), serotonin (5-HT), norepinephrine (NE) and γ-aminobutyric acid (GABA). Rapid eye movement sleep deprivation (REMSD) alters most of the neurotransmitters, which may have adverse behavioural changes and other health consequences like mania and other psychiatric disorders. The exact role of REMSD altered neurotransmitter levels and the manner in which emerging consequences lead to mania-like behaviour is poorly understood. Thus, we sought to verify the levels of neurotransmitter changes after 48, 72 and 96 h of REMSD induced mania-like behaviour in mice. We performed modified multiple platform (MMP) method of depriving the REM sleep and one group maintained as a control. To measure the hyperactivity through locomotion, exploration and behavioural despair, we performed the Open Field Test (OFT) and the Forced Swim Test (FST). Quantitative determinations of DA, 5-HT, NE and GABA concentrations in four distinct brain regions (cerebral cortex, hippocampus, midbrain, and pons) were determined by the spectrofluorimetric method. These experiments showed higher locomotion and increased swimming, struggling/climbing and decreased mobility among REMSD animals as well as disrupted concentrations of the majority of the studied neurotransmitters during REMSD. Our study indicated that REMSD results in mania-like behaviour in mice and associated disruption to neurotransmitter levels, although the exact mechanisms by which these take place remain to be determined.

Quantitative genetic analysis of anxiety trait in bipolar disorder

BACKGROUND

Bipolar disorder type I (BPI) affects approximately 1% of the world population. Although genetic influences on bipolar disorder are well established, identification of genes that predispose to the illness has been difficult. Most genetic studies are based on categorical diagnosis. One strategy to overcome this obstacle is the use of quantitative endophenotypes, as has been done for other medical disorders.

METHODS

We studied 619 individuals, 568 participants from 61 extended families and 51 unrelated healthy controls. The sample was 55% female and had a mean age of 43.25 (SD 13.90; range 18-78). Heritability and genetic correlation of the trait scale from the Anxiety State and Trait Inventory (STAI) was computed by using the general linear model (SOLAR package software).

RESULTS

we observed that anxiety trait meets the following criteria for an endophenotype of bipolar disorder type I (BPI): 1) association with BPI (individuals with BPI showed the highest trait score (F = 15.20 [5,24], p = 0.009), 2) state-independence confirmed after conducting a test-retest in 321 subjects, 3) co-segregation within families 4) heritability of 0.70 (SE: 0.060), p = 2.33 × 10^-14 and 5) genetic correlation with BPI was 0.20, (SE = 0.17, p = 3.12 × 10^-5).

LIMITATIONS

Confounding factors such as comorbid disorders and pharmacological treatment could affect the clinical relationship between BPI and anxiety trait. Further research is needed to evaluate if anxiety traits are specially related to BPI in comparison with other traits such as anger, attention or response inhibition deficit, pathological impulsivity or low self-directedness.

CONCLUSIONS

Anxiety trait is a heritable phenotype that follows a normal distribution when measured not only in subjects with BPI but also in unrelated healthy controls. It could be used as an endophenotype in BPI for the identification of genomic regions with susceptibility genes for this disorder.

Lithium ameliorates sleep deprivation-induced mania-like behavior, hypothalamic-pituitary-adrenal (HPA) axis alterations, oxidative stress and elevations of cytokine concentrations in the brain and serum of mice

OBJECTIVES

The goal of the present study was to investigate the effects of lithium administration on behavior, oxidative stress parameters and cytokine levels in the periphery and brain of mice subjected to an animal model of mania induced by paradoxical sleep deprivation (PSD).

METHODS

Male C57 mice were treated with saline or lithium for 7 days. The sleep deprivation protocol started on the 5th day during for the last 36 hours of the treatment period. Immediately after the sleep deprivation protocol, animals locomotor activity was evaluated and serum and brain samples was extracted to evaluation of corticosterone and adrenocorticotropic hormone circulating levels, oxidative stress parameters and citokynes levels.

RESULTS

The results showed that PSD induced hyperactivity in mice, which is considered a mania-like behavior. PSD increased lipid peroxidation and oxidative damage to DNA, as well as causing alterations to antioxidant enzymes in the frontal cortex, hippocampus and serum of mice. In addition, PSD increased the levels of cytokines in the brains of mice. Treatment with lithium prevented the mania-like behavior, oxidative damage and cytokine alterations induced by PSD.

CONCLUSIONS

Improving our understanding of oxidative damage in biomolecules, antioxidant mechanisms and the inflammatory system - alterations presented in the animal models of mania - is important in helping us to improve our knowledge concerning the pathophysiology of BD, and the mechanisms of action employed by mood stabilizers.

Deep brain stimulation for bipolar disorder-review and outlook

Research on deep brain stimulation (DBS) for treatment-resistant psychiatric disorders has established preliminary efficacy signals for treatment-resistant depression. There are only few studies on DBS that included patients suffering from bipolar disorder. This article gives an overview of these studies concerning DBS targets, antidepressant efficacy, and the occurrence of manic/hypomanic symptoms under stimulation. First, promising results show that all patients experienced significant improvement in depressive symptomatology. In a single case, hypomanic symptoms occurred, but they could be resolved by adjusting stimulation parameters. Furthermore, this article highlights important clinical differences between unipolar and bipolar depression that have to be considered throughout the course of treatment.

Natural and synthetic bioactive inhibitors of glycogen synthase kinase

Glycogen synthase kinase-3 is a multi-functional serine-threonine kinase and is involved in diverse physiological processes, including metabolism, cell cycle, and gene expression by regulating a wide variety of known substrates like glycogen synthase, tau-protein and β-catenin. Aberrant GSK-3 has been involved in diabetes, inflammation, cancer, Alzheimer's and bipolar disorder. In this review, we present an overview of the involvement of GSK-3 in various signalling pathways, resulting in a number of adverse pathologies due to its dysregulation. In addition, a detailed description of the small molecule inhibitors of GSK-3 with different mode of action discovered or specifically developed for GSK-3 has been presented. Furthermore, some clues for the future optimization of these promising molecules to develop specific drugs inhibiting GSK-3, for the treatment of associated disease conditions have also been discussed.

Toward a complex system understanding of bipolar disorder: A chaotic model of abnormal circadian activity rhythms in euthymic bipolar disorder

IMPORTANCE

In the absence of a comprehensive neural model to explain the underlying mechanisms of disturbed circadian function in bipolar disorder, mathematical modeling is a helpful tool. Here, circadian activity as a response to exogenous daily cycles is proposed to be the product of interactions between neuronal networks in cortical (cognitive processing) and subcortical (pacemaker) areas of the brain.

OBJECTIVE

To investigate the dynamical aspects of the link between disturbed circadian activity rhythms and abnormalities of neurotransmitter functioning in frontal areas of the brain, we developed a novel mathematical model of a chaotic system which represents fluctuations in circadian activity in bipolar disorder as changes in the model's parameters.

DESIGN, SETTING AND PARTICIPANTS

A novel map-based chaotic system was developed to capture disturbances in circadian activity across the two extreme mood states of bipolar disorder. The model uses chaos theory to characterize interplay between neurotransmitter functions and rhythm generation; it aims to illuminate key activity phenomenology in bipolar disorder, including prolonged sleep intervals, decreased total activity and attenuated amplitude of the diurnal activity rhythm. To test our new cortical-circadian mathematical model of bipolar disorder, we utilized previously collected locomotor activity data recorded from normal subjects and bipolar patients by wrist-worn actigraphs.

RESULTS

All control parameters in the proposed model have an important role in replicating the different aspects of circadian activity rhythm generation in the brain. The model can successfully replicate deviations in sleep/wake time intervals corresponding to manic and depressive episodes of bipolar disorder, in which one of the excitatory or inhibitory pathways is abnormally dominant.

CONCLUSIONS AND RELEVANCE

Although neuroimaging research has strongly implicated a reciprocal interaction between cortical and subcortical regions as pathogenic in bipolar disorder, this is the first model to mathematically represent this multilevel explanation of the phenomena of bipolar disorder.

The effects of n-acetylcysteine and/or deferoxamine on manic-like behavior and brain oxidative damage in mice submitted to the paradoxal sleep deprivation model of mania

Bipolar disorder (BD) is a severe psychiatric disorder associated with social and functional impairment. Some studies have strongly suggested the involvement of oxidative stress in the pathophysiology of BD. Paradoxal sleep deprivation (PSD) in mice has been considered a good animal model of mania because it induces similar manic-like behavior, as well as producing the neurochemical alterations which have been observed in bipolar patients. Thus, the objective of the present study was to evaluate the effects of the antioxidant agent's n-acetylcysteine (Nac) and/or deferoxamine (DFX) on behavior and the oxidative stress parameters in the brains of mice submitted to the animal model of mania induced by PSD. The mice were treated for a period of seven days with saline solution (SAL), Nac, DFX or Nac plus DFX. The animals were subject to the PSD protocol for 36 h. Locomotor activity was then evaluated using the open-field test, and the oxidative stress parameters were subsequently evaluated in the hippocampus and frontal cortex of mice. The results showed PSD induced hyperactivity in mice, which is considered a manic-like behavior. In addition to this, PSD increased lipid peroxidation and oxidative damage to proteins, as well as causing alterations to antioxidant enzymes in the frontal cortex and hippocampus of mice. The Nac plus DFX adjunctive treatment prevented both the manic-like behavior and oxidative damage induced by PSD. Improving our understanding relating to oxidative damage in biomolecules, and the antioxidant mechanisms presented in the animal models of mania are important in helping to improve our knowledge concerning the pathophysiology and development of new therapeutical treatments for BD.

Towards a complex system understanding of bipolar disorder: A map based model of a complex winnerless competition

Bipolar disorder is characterized by repeated erratic episodes of mania and depression, which can be understood as pathological complex system behavior involving cognitive, affective and psychomotor disturbance. In order to illuminate dynamical aspects of the longitudinal course of the illness, we propose here a novel complex model based on the notion of competition between recurrent maps, which mathematically represent the dynamics of activation in excitatory (Glutamatergic) and inhibitory (GABAergic) pathways. We assume that manic and depressive states can be considered stable sub attractors of a dynamical system through which the mood trajectory moves. The model provides a theoretical framework which can account for a number of complex phenomena of bipolar disorder, including intermittent transition between the two poles of the disorder, rapid and ultra-rapid cycling of episodes and manicogenic effects of antidepressants.

Deep brain stimulation for major depression

A third of patients suffering from major depression cannot be helped by conventional treatment methods. These patients face reduced quality of life, high risk of suicide, and little hope of recovery. Deep brain stimulation (DBS) is under scientific evaluation as a new treatment option for these treatment-resistant patients. First clinical studies with small samples have been stimulated at the subgenual cingulate gyrus (Cg25/24), the anterior limb of the capsula interna (ALIC), and the nucleus accumbens (NAcc). Long-term antidepressant effects, augmentation of social functioning, and normalization of brain metabolism have been shown in about 50% of patients. Cognitive safety regarding attention, learning, and memory has been reported. Adverse events were wound infection, suicide, and hypomania, amongst others. Larger studies are under way to confirm these preliminary encouraging results. New hypothesis-guided targets (e.g., medial forebrain bundle, habenula) are about to be assessed in clinical trials. The application of DBS for other psychiatric diseases (e.g., bipolar disorder, alcohol dependency, opioid addiction, schizophrenia) is debated and single case studies are under way. Standards are needed for study registration, target selection, patient inclusion and monitoring, and publication of results to guarantee safety for the patients and scientific exchange.

The relationship between oxidative stress and post-translational modification of the dopamine transporter in bipolar disorder

Bipolar disorder (BD) has been consistently associated with altered levels of oxidative stress markers, although the cause and consequences of these alterations remain to be elucidated. One of the main hypotheses regarding the pathogenesis of mania involves increased dopaminergic transmission. In this review, the authors aim to discuss a potential mechanism by which increased oxidative stress inhibits the uptake of dopamine through the post-translational modification of the dopamine transporter and its implications for BD. Within the next 5 years, the authors believe that the mechanisms of dopamine transporter oxidation and its impact on the pathophysiology of BD will be elucidated, which may open avenues for the development of more specific interventions for the treatment of this debilitating illness.

Lack of association to a NRG1 missense polymorphism in schizophrenia or bipolar disorder in a Costa Rican population

A missense polymorphism in the NRG1 gene, Val>Leu in exon 11, was reported to increase the risk of schizophrenia in selected families from the Central Valley region of Costa Rica (CVCR). The present study investigated the relationship between three NRG1 genetic variants, rs6994992, rs3924999, and Val>Leu missense polymorphism in exon 11, in cases and selected controls from an isolated population from the CVCR. Isolated populations can have less genetic heterogeneity and increase power to detect risk variants in candidate genes. Subjects with bipolar disorder (BD, n=358), schizophrenia (SZ, n=273), or unrelated controls (CO, n=479) were genotyped for three NRG1 variants. The NRG1 promoter polymorphism (rs6994992) was related to altered expression of NRG1 Type IV in other studies. The expression of NRG1 type IV in the dorsolateral prefrontal cortex (DLPFC) and the effect of the rs6994992 genotype on expression were explored in a postmortem cohort of BD, SZ, major depressive disorder (MDD) cases, and controls. The missense polymorphism Val>Leu in exon 11 was not significantly associated with schizophrenia as previously reported in a family sample from this population, the minor allele frequency is 4%, thus our sample size is not large enough to detect an association. We observed however an association of rs6994992 with NRG1 type IV expression in DLPFC and a significantly decreased expression in MDD compared to controls. The present results while negative do not rule out a genetic association of these SNPs with BD and SZ in CVCR, perhaps due to small risk effects that we were unable to detect and potential intergenic epistasis. The previous genetic relationship between expression of a putative brain-specific isoform of NRG1 type IV and SNP variation was replicated in postmortem samples in our preliminary study.

Glycogen synthase kinase-3 in the etiology and treatment of mood disorders

The mood disorders major depressive disorder and bipolar disorder are prevalent, are inadequately treated, and little is known about their etiologies. A better understanding of the causes of mood disorders would benefit from improved animal models of mood disorders, which now rely on behavioral measurements. This review considers the limitations in relating measures of rodent behaviors to mood disorders, and the evidence from behavioral assessments indicating that glycogen synthase kinase-3 (GSK3) dysregulation promotes mood disorders and is a potential target for treating mood disorders. The classical mood stabilizer lithium was identified by studying animal behaviors and later was discovered to be an inhibitor of GSK3. Several mood-relevant behavioral effects of lithium in rodents have been identified, and most have now been shown to be due to its inhibition of GSK3. An extensive variety of pharmacological and molecular approaches for manipulating GSK3 are discussed, the results of which strongly support the proposal that inhibition of GSK3 reduces both depression-like and manic-like behaviors. Studies in human postmortem brain and peripheral cells also have identified correlations between alterations in GSK3 and mood disorders. Evidence is reviewed that depression may be associated with impaired inhibitory control of GSK3, and mania by hyper-stimulation of GSK3. Taken together, these studies provide substantial support for the hypothesis that inhibition of GSK3 activity is therapeutic for mood disorders. Future research should identify the causes of dysregulated GSK3 in mood disorders and the actions of GSK3 that contribute to these diseases.

Successful combined therapy with tamoxifen and lithium in a paradoxical sleep deprivation-induced mania model

BACKGROUND

Previous studies have suggested that manic states and sleep deprivation could contribute to the pathophysiology of bipolar disorder (BD) through protein kinase C (PKC) signaling abnormalities. Moreover, adjunctive therapy has become a standard strategy in the management of BD patients who respond poorly to current pharmacological treatments.

AIM

Thus, the aim of this study was to investigate the possible involvement of PKC inhibition by tamoxifen both separately or in combination with lithium, in paradoxical sleep deprivation (PSD)-induced hyperactivity, one facet of mania-like behavior.

MATERIALS & METHODS

Adult male C57BL/6J mice were randomly distributed (n = 7/group) in 24-h PSD or control groups and injected intraperitoneally (i.p.) with vehicle, lithium (50, 100, or 150 mg/kg) or tamoxifen (0.5, 1.0, or 2.0 mg/kg - experiment 1). In a second experiment, mice were injected i.p. with vehicle or a combination of subeffective doses of lithium and tamoxifen. Animals were subjected to a protocol based on repetitive PSD conditions, followed by assessment of locomotion activity in the open-field task.

RESULTS

PSD significantly increased locomotor activity in both experiments. These behavioral changes were prevented by a treatment with lithium or tamoxifen, or a combined treatment with both lithium and tamoxifen.

DISCUSSION

Therefore, our findings suggest that lithium and tamoxifen exert reversal effects against PSD-induced hyperactivity in mice.

CONCLUSION

Furthermore, tamoxifen as an adjunct to lithium therapy provides support for an alternative treatment of individuals who either do not respond adequately or cannot tolerate the adverse effects associated with therapeutic doses of lithium.

The structure of cognitive abilities in youths with manic symptoms: a factorial invariance study

This study compared the structure of cognitive ability (specifically, verbal/crystallized [Gc] and visual-spatial ability [Gv]), as measured in the Wechsler Intelligence Scale for Children, in youth with manic symptoms with a nationally representative group of similarly aged youth. Multigroup confirmatory factor analysis found the majority of the estimated parameters were invariant between the groups, although there was a difference in the intercepts for the Similarities subtest and difference in unique variances for the Picture Completion, Comprehension, and Picture Arrangement subtests. Thus, although there are many neurological changes associated with manic symptoms, the structure of verbal/crystallized and visual-spatial abilities appear relatively robust and invariant. As Gc and Gv are the primary domains on all the Wechsler Intelligence Scales for Children, results also indicate that clinical interpretation of the Wechsler scales may be appropriate to measure cognitive performance in youths with manic symptoms.

Abnormalities in mitochondrial structure in cells from patients with bipolar disorder

Postmortem, genetic, brain imaging, and peripheral cell studies all support decreased mitochondrial activity as a factor in the manifestation of Bipolar Disorder (BD). Because abnormal mitochondrial morphology is often linked to altered energy metabolism, we investigated whether changes in mitochondrial structure were present in brain and peripheral cells of patients with BD. Mitochondria from patients with BD exhibited size and distributional abnormalities compared with psychiatrically-healthy age-matched controls. Specifically, in brain, individual mitochondria profiles had significantly smaller areas, on average, in BD samples (P = 0.03). In peripheral cells, mitochondria in BD samples were concentrated proportionately more within the perinuclear region than in distal processes (P = 0.0008). These mitochondrial changes did not appear to be correlated with exposure to lithium. Also, these abnormalities in brain and peripheral cells were independent of substantial changes in the actin or tubulin cytoskeleton with which mitochondria interact. The observed changes in mitochondrial size and distribution may be linked to energy deficits and, therefore, may have consequences for cell plasticity, resilience, and survival in patients with BD, especially in brain, which has a high-energy requirement. The findings may have implications for diagnosis, if they are specific to BD, and for treatment, if they provide clues as to the underlying pathophysiology of BD.

Is subclinical anxiety an endophenotype for bipolar I patients? A study from a Costa Rican sample

BACKGROUND

Although genetic influences on bipolar I disorder are well established, localization of genes that predispose to the illness has been difficult. Some genes predisposing to bipolar I disorder may be transmitted without expression of the categorical clinical phenotype. One strategy to overcome this obstacle is the use of quantitative endophenotypes, as has been done for other medical disorders.

METHODS

We analyzed 30 bipolar I extended families (300 subjects, average family size 10.34 members, range: 2-31) and 20 unrelated healthy controls from a Costa Rican sample. Heritability and genetic correlation of the state and trait scale from the Anxiety State and Trait Inventory was computed by using the general linear model (SOLAR package software). We also assessed variation of both scores among groups (patients, relatives and controls) and tested independence of affection status.

RESULTS

Heritability for state is 0.45 (SE=0.11, p=0.0000001) and for trait is 0.89 (SE=0.06, p=6.22e-29). Genetic correlation for state and trait is 0.29, (SE=0.12, p=0.038-3.19e-8). Bipolar I patients showed the highest trait score (F=12.17 [5,24], p=0.002), (bipolar I patients>relatives with other pathologies, >healthy relatives>unrelated healthy controls) with normal distribution in healthy individuals and no difference regarding depression and mania current status, (F=0.230, df=1, p=0.632 and F=1.401, df=1, p=0.238, respectively), contrary to the state score.

LIMITATIONS

Confounding factors such as comorbid disorders could affect the interaction of subclinical anxiety with mania. Due to our limited budget we were not able to re-evaluate the subjects and conduct a test retest to assess the STAI reliability and mood state independence of anxiety traits over different times. Further research is needed to evaluate if anxiety traits are specially related to bipolar I disorder in comparison with other traits such as anger, attention or response inhibition deficit, pathological impulsivity or low self-directedness.

CONCLUSIONS

Anxiety state and trait are heritable and share some genetic factors but only trait showed normal distribution in healthy subjects, mood current status independence and significant liability for bipolar I disorder. A stair-step distribution of trait anxiety scores in the family members and controls based on their genetic proximity to affected individuals and diagnostic status suggests that trait anxiety could be an endophenotype in these bipolar I families.

Gender differences in prepulse inhibition (PPI) in bipolar disorder: men have reduced PPI, women have increased PPI

Prepulse inhibition (PPI) is a measure of sensorimotor gating or information processing. Few studies have examined PPI in bipolar disorder (BD); two studies reported a PPI disruption and two reported no change. There are gender differences in PPI and within the clinical profile of BD, which may explain some of these discrepancies. Thus, the effect of gender on PPI in BD was the focus of the current study. Euthymic BD patients (14 male/15 female) were compared to age- and IQ-matched healthy control participants (16 male/16 female). Assessment of PPI included 21 pulse-alone trials (115 dB) and a total of 42 prepulse-pulse trials (seven of each prepulse: 74, 78, 86 dB) at two stimulus onset asynchrony levels (SOA: 60, 120 ms). There was a group x SOA and a group x gender interaction, reflecting that men with BD showed reduced PPI compared to control males at the 60-ms SOA (3% in BD vs. 26% in controls), but not the 120-ms SOA. In contrast, women with BD had significantly increased PPI compared to female controls at the 120-ms SOA (49% in BD vs. 29% in controls), but not the 60-ms SOA. Compared to control participants BD patients showed changes in PPI, which are gender-dependent; male BD participants had reduced PPI, whereas female BD participants had increased PPI. This gender difference highlights the need to consider men and women with BD as two distinct groups, at least in PPI studies.

Premorbid adjustment: a phenotype highlighting a distinction rather than an overlap between schizophrenia and bipolar disorder

BACKGROUND

Premorbid adjustment (PMA) in schizophrenia (SZ) has been widely studied and shown to be worse in individuals who develop SZ as compared to controls. It has been proposed as a predictor of clinical presentation and outcome, and may delineate a specific SZ phenotype for genetic and other biological studies. Research into PMA in BD has been scarce and inconclusive.

AIMS

The authors compared PMA in individuals suffering from BD with that of healthy controls and investigated whether levels of PMA in BD patients correlate with specific phenotypic features.

METHODS

The authors investigated 344 BD patients and 137 population-based controls. Retrospective PMA assessment was performed using the Premorbid Adjustment Scale (PAS). An overall score as well as sub-scores for age ranges and functional domains were obtained.

RESULTS

Patients had a better overall PAS score than controls and outperformed controls during early and late adolescence. They scored significantly better than controls in the functional domains "sociability and withdrawal" and "adaptation to school". No differences were observed for the other subscales and there were no differences between groups during childhood. No association was observed between PMA and any of the phenotype characteristics investigated.

CONCLUSIONS

In the largest study to date on PMA in BD, PMA was shown to be better in bipolar patients than in healthy controls. PMA in BD is not a simple proxy for commonly studied phenotypic markers of severity. PMA emerges as a phenotype in its own right, and highlights an aspect of disparity rather than overlap between SZ and BD.

Aberrant amino acid transport in fibroblasts from patients with bipolar disorder

Aberrant tyrosine transport is a repeated finding in fibroblasts from schizophrenic patients. The transport aberration could lead to disturbances in the dopaminergic and noradrenergic neurotransmitter systems. Tyrosine and tryptophan are the precursors of the neurotransmitters dopamine and serotonin. Disturbed dopaminergic, noradrenergic and serotoninergic systems are implicated as causes of bipolar disorder. Hence, the aim of this study was to explore whether patients with bipolar disorder have an aberrant transport of tyrosine and/or tryptophan. Fibroblast cell lines from patients with bipolar type-1 disorder (n=10) and healthy controls (n=10) were included in this study. All patients fulfilled the DSM-IV diagnostic criteria. The transport of amino acids across the cell membranes was measured by the cluster tray method. The kinetic parameters, maximal transport velocity (V(max)) and affinity constant (K(m)) were determined. A significantly lower V(max) for tyrosine (p=0.027) was found in patients with bipolar type-1 disorder in comparison to healthy controls. No significant differences in K(m) for tyrosine and in the kinetic parameters of tryptophan between patients with bipolar type-1 disorder and healthy controls were observed. The decreased tyrosine transport (low V(max)) found in this study may indicate less access of dopamine in the brain, resulting in disturbed dopaminergic and/or noradrenergic neurotransmission, that secondarily could lead to disturbances in other central neurotransmitter systems, such as the serotoninergic system. However, as sample size was small in this study and an age difference between patients and controls existed, the present findings should be considered as pilot data. Further studies with larger sample number are needed to elucidate the transport aberration and the significance of these findings.

Antidepressant-like effect of the novel thiadiazolidinone NP031115 in mice

Glycogen synthase kinase-3beta (GSK-3beta) is an enzyme that phosphorylates glycogen synthase, thereby inhibiting glycogen synthesis. Besides this role, it is now believed that this enzyme plays an important role in the pathophysiology of many brain diseases including depression. Some inhibitors of this enzyme have shown antidepressant effects in animal models. This study investigated the effects of a novel thiadiazolidinone NP031115, a putative GSK-3beta inhibitor, and the well-established GSK-3beta inhibitor AR-A014418 in the mouse forced swimming test (FST), a model widely used to evaluate antidepressant activity. We found that NP031115 had an IC50 of 1.23 and 6.5 microM for GSK-3beta and GSK-3alpha, respectively. NP031115 (0.5 and 5 mg/kg, i.p.), in a way similar to imipramine (15 mg/kg, i.p), fluoxetine (32 mg/kg, i.p), AR-A014418 (9 mg/kg, i.p.), and rosiglitazone (5 microg/site, i.c.v.), significantly reduced immobility time in the FST. NP031115 at the higher dose and AR-A014418 (9 mg/kg, i.p.) reduced locomotion in the open-field test. Rosiglitazone (30 microM), AR-A014418 (1 microM), PG(J2) (10 microM), and NP031115 (1, 10 and 25 microM) activate PPARgamma in CHO transfected cells. GW-9662 (10 microg/site, i.c.v, a PPARgamma antagonist) administered 15 min before NP03115 (5 mg/kg, i.p.) or co-administered with rosiglitazone (5 microg/site, i.c.v.) prevented the antidepressant-like effect of these drugs in the FST. The results of this study show that NP031115 can exhibit an antidepressant effect, likely by inhibiting GSK-3beta and enhancing PPARgamma activity.

Social phobia is associated with suicide attempt history in bipolar inpatients

OBJECTIVES

In an attempt to reduce the phenotypical heterogeneity in an ongoing genetic study of suicidal behavior, we investigated the impact of comorbid anxiety disorders on suicidal behavior in bipolar disorder (BD) patients.

METHODS

Anxiety disorders were compared in 406 BD I and BD II patients with or without lifetime history of suicide attempt.

RESULTS

Among anxiety disorders, only social phobia (SP) was significantly associated with history of suicide attempt in BD [p<0.001, odds ratio 4.26 (2.284-7.946)]. Moreover, onset of SP was found to precede onset of BD.

CONCLUSIONS

This result suggests that SP is an important risk factor for suicidal behavior in BD. Further studies are required to determine whether comorbid SP may help to identify a more homogeneous BD sub-group, especially when studies of suicidal behavior are conducted. A second question is whether SP identifies a sub-group of subjects with BD who have a more severe illness course and whether treatment of SP with selective serotonin reuptake inhibitor (SSRI) antidepressants is associated with improvement or worsening of the course of BD.

A final common pathway for depression? Progress toward a general conceptual framework

Functional neuroimaging studies of depressed patients have converged with functional brain mapping studies of depressed animals in showing that depression is accompanied by a hypoactivity of brain regions involved in positively motivated behavior together with a hyperactivity in regions involved in stress responses. Both sets of changes are reversed by diverse antidepressant treatments. It has been proposed that this neural pattern underlies the symptoms common to most forms of the depression, which are the loss of positively motivated behavior and increased stress. The paper discusses how this framework can organize diverse findings ranging from effects of monoamine neurotransmitters, cytokines, corticosteroids and neurotrophins on depression. The hypothesis leads to new insights concerning the relationship between the prolonged inactivity of the positive motivational network during a depressive episode and the loss of neurotrophic support, the potential antidepressant action of corticosteroid treatment, and to the key question of whether antidepressants act by inhibiting the activity of the stress network or by enhancing the activity of the positive motivational system.

A final common pathway for depression: implications for therapy

Depression in humans and animal models has been found to be accompanied by a hypoactivity of brain regions involved in positively motivated behavior together with a hyperactivity in regions involved in stress responses. Both sets of changes are reversed by diverse antidepressant treatments. It has been proposed that this neural pattern underlies the symptoms common to most forms of depression, which are the loss of positively motivated behavior and the increase in stress. The present paper discusses how this framework can organize diverse findings on the multiple factors associated with this disorder. The hypothesis suggests new therapeutic strategies involving treatment with low-dose corticosteroids to suppress the stress network or with antagonists of alpha(1A)- and agonists of alpha(1B)-adrenoceptors to disinhibit or activate the positive motivational network, respectively.

A prospective study of the association of cerebrospinal fluid monoamine metabolite levels with lethality of suicide attempts in patients with bipolar disorder

OBJECTIVES

Bipolar disorder is a severe illness that is associated with suicidal behavior. A biological predictor of highly lethal suicide attempts in patients with bipolar disorder would be valuable. We hypothesized that cerebrospinal fluid (CSF) monoamine metabolite levels are related to lethality of suicide attempts in bipolar patients and examined the relation between CSF 5-hydroxyindolacetic acid (5-HIAA), homovanillic acid (HVA), and 3-methoxy-4-hydroxyphenylglycol (MHPG) levels and maximum lethality of suicide attempts at baseline and during a 2-year follow up.

METHODS

Twenty-seven bipolar depressed patients participated in the study. Demographic and clinical parameters were examined and recorded. Lumbar punctures were performed and CSF 5-HIAA, HVA, and MHPG were assayed by high-performance liquid chromatography with electrochemical detection. Following discharge, patients were evaluated after 3 months, 1 year, and 2 years. Each follow-up interview included an in-depth assessment of suicidal behavior during the intervening time period.

RESULTS

Six subjects made suicide attempts during the 2-year follow-up. Bipolar patients who attempted suicide during the follow-up period had higher aggression and hostility scale scores compared to bipolar subjects who did not make a suicide attempt during the follow-up period. CSF 5-HIAA, HVA, and MHPG levels were negatively correlated with the maximum lethality of suicide attempts during the 2-year follow-up period.

CONCLUSIONS

Our finding is the first observation that CSF monoamine metabolite levels may be predictors of lethality of suicide attempts in patients with bipolar disorder. Further studies are necessary to answer the question whether CSF monoamine metabolite levels are clinically useful biochemical predictors of highly lethal suicide attempts or completed suicides.

Explicit and implicit facial affect recognition in manic and depressed States of bipolar disorder: a functional magnetic resonance imaging study

BACKGROUND

The pathophysiology of abnormal mood states-mania and depression-in patients with bipolar disorder remains unclear. Facial affect processing paradigms are an effective way of studying behavioral and functional magnetic resonance imaging (fMRI) correlates of affective disorders.

METHODS

We used a factorial design to measure the neural correlates of tasks, tapping explicit and implicit recognition of sad, fearful, and happy facial expressions using event-related fMRI paradigms in three groups of participants: eight bipolar depressed patients, eight bipolar manic patients, and eight control subjects.

RESULTS

Depressed and manic patients exhibited overactivated responses to fearful faces, as well as to mood-incongruent facial expressions, with the depressed group exhibiting overactivity in fronto-striato-thalamic systems in response to happy faces and the manic group exhibiting overactivity in the fusiform gyrus in response to sad faces. For manic patients, task type also affected the neural response to sad faces, with the corticolimbic regions showing overactivation for implicit processing and underactivation for explicit processing.

CONCLUSIONS

Depressed and manic patients exhibited abnormal neural responses to sad, fearful, and happy facial expressions. Additionally, the attentional level of sad facial affect processing has important consequences for abnormalities of amygdala and cingulate activation in manic patients.