Biological aspects and candidate biomarkers for psychotic bipolar disorder: A systematic review

Biomarkers for Psychosis: Are We There Yet? Umbrella Review of 1478 Biomarkers

Background and Hypothesis

This umbrella review aims to comprehensively synthesize the evidence of association between peripheral, electrophysiological, neuroimaging, neuropathological, and other biomarkers and diagnosis of psychotic disorders.

Study Design

We selected systematic reviews and meta-analyses of observational studies on diagnostic biomarkers for psychotic disorders, published until February 1, 2018. Data extraction was conducted according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. Evidence of association between biomarkers and psychotic disorders was classified as convincing, highly suggestive, suggestive, weak, or non-significant, using a standardized classification. Quality analyses used the Assessment of Multiple Systematic Reviews (AMSTAR) tool.

Study Results

The umbrella review included 110 meta-analyses or systematic reviews corresponding to 3892 individual studies, 1478 biomarkers, and 392 210 participants. No factor showed a convincing level of evidence. Highly suggestive evidence was observed for transglutaminase autoantibodies levels (odds ratio [OR] = 7.32; 95% CI: 3.36, 15.94), mismatch negativity in auditory event-related potentials (standardized mean difference [SMD] = 0.73; 95% CI: 0.5, 0.96), P300 component latency (SMD = -0.6; 95% CI: -0.83, -0.38), ventricle-brain ratio (SMD = 0.61; 95% CI: 0.5, 0.71), and minor physical anomalies (SMD = 0.99; 95% CI: 0.64, 1.34). Suggestive evidence was observed for folate, malondialdehyde, brain-derived neurotrophic factor, homocysteine, P50 sensory gating (P50 S2/S1 ratio), frontal N-acetyl-aspartate, and high-frequency heart rate variability. Among the remaining biomarkers, weak evidence was found for 626 and a non-significant association for 833 factors.

Conclusions

While several biomarkers present highly suggestive or suggestive evidence of association with psychotic disorders, methodological biases, and underpowered studies call for future higher-quality research.

Impaired olfactory function in bipolar disorder patients during acute episodes regardless of psychotic symptoms

Background

The aim of this study was to analyze whether the presence of psychotic symptoms affects olfactory function in patients with bipolar disorder (BD). We also compared olfactory function between the period of episode and remission in patients with BD.

Methods

BD patients in the acute phase were tracked to the remission stage. The psychiatric symptoms and social function of the enrolled subjects were assessed using the Hamilton Rating Scale for Depression (HAMD), the Young Mania Rating Scale (YMRS), the Hamilton Rating Scale for Anxiety (HAMA), the Positive and Negative Syndrome Scale (PANSS) and the Global Assessment Function (GAF). Olfactory sensitivity (OS) and olfactory identification (OI) was assessed using the Sniffin' Sticks test. Differences in OS and OI among the episodic group, the euthymic group, and the healthy control (HC) group were compared. According to whether BD is accompanied by psychotic symptoms, the OS and OI in the BD with psychotic symptoms group (P-BD), the BD without psychotic symptoms group (NP-BD), and the HC group were compared.

Results

The P-BD and NP-BD groups exhibited impaired OI compared with the HC group, but there was no significant difference in OI between the P-BD and NP-BD groups, or in OS among all three groups. All patients with episodic BD had significantly lower OS and OI compared with the HC group. OI in euthymic BD patients was still impaired; however, OS recovered, showing no significant difference compared with that in the HC group.

Conclusion

The results indicate that patients with episodic BD have impaired OS and OI, regardless of psychotic symptoms. OI may be a characteristic marker of BD, and OS may be a state marker that can be used to distinguish between episodic and euthymic BD.

Are There Any Differences in Clinical and Biochemical Variables between Bipolar Patients with or without Lifetime Psychotic Symptoms?

INTRODUCTION

Psychotic symptoms occur in more than half of patients affected by Bipolar Disorder (BD) and are associated with an unfavorable course of the disorder. The objective of this study is to identify the differences in the clinical and biochemical parameters between bipolar patients with or without psychotic symptoms.

METHODS

A total of 665 inpatients were recruited. Demographic, clinical, and biochemical data related to the first day of hospitalization were obtained via a screening of the clinical charts and intranet hospital applications. The two groups identified via the lifetime presence of psychotic symptoms were compared using t tests for quantitative variables and χ2 tests for qualitative ones; binary logistic regression models were subsequently performed.

RESULTS

Patients with psychotic BD (compared to non-psychotic ones) showed a longer duration of hospitalization (p < 0.001), higher Young Mania Rating Scale scores (p < 0.001), lower Global Assessment of Functioning scores (p = 0.002), a less frequent history of lifetime suicide attempts (p = 0.019), less achievement of remission during the current hospitalization (p = 0.028), and a higher Neutrophile to Lymphocyte Ratio (NLR) (p = 0.006), but lower total cholesterol (p = 0.018) and triglycerides (p = 0.013).

CONCLUSIONS

Patients with psychotic BD have a different clinical and biochemical profile compared to their counterparts, characterized by more clinical severity, fewer metabolic alterations, and a higher grade of inflammation. Further multi-center studies have to confirm the results of this present study.

Psychotic symptoms and neurocognition among patients with major depressive disorder: A chained mediation model of depressive symptoms and socio-occupational functioning

BACKGROUND

Depressive symptom and psychotic symptom have been identified as risk factors for impaired socio-occupational functioning in patients with major depressive disorder (MDD), while neurocognitive functioning is considered to be a potential protective factor against socio-occupational functioning. Nevertheless, little is known about the complex relationship among these factors in patients with MDD. The purpose of this research was to explore whether the relationship between depressive symptom severity and social-occupational functioning is mediated by neurocognitive functioning and psychotic symptom severity in MDD patients.

METHODS

A total of 659 eligible MDD patients included male and female, and their depressive symptoms and psychotic symptoms at baseline were assessed by the 17-item Hamilton Depression Scale (HAMD-17) and The Brief Psychiatric Rating Scale (BPRS) respectively. Cognitive domains were assessed by the MATRICS Consensus Cognitive Battery (MCCB), and subjective and objective functioning were measured by the Global Assessment of Functioning (GAF).

LIMITATION

The analysis is cross-sectional, which limits causal inference.

RESULT

(1) The correlation between depressive symptoms and thought disturbance was positive (r = 0.125, p = 0.001), whereas the correlations with visual learning and memory (r = -0.146, p < 0.001) and socio-occupational functioning (r = -0.175, p < 0.001) were negative. (2) Depressive symptoms mainly affect the socio-occupational functioning of MDD patients via three indirect effects: the single mediating effect of psychotic symptoms and neurocognitive functioning, and the chain mediating effect of psychotic symptoms and neurocognitive functioning.

CONCLUSIONS

The results suggest that the relationship between depressive symptom severity and socio-occupational functioning in MDD patients is partially mediated by psychotic symptom severity and neurocognitive functioning.

Neurological and cerebellar soft signs in bipolar disorder: The role of staging, type and history of psychotic symptoms

AIM

Bipolar disorder (BD) patients show neurological abnormalities in form of neurological and cerebellar soft signs (NSS and CSS). NSS represents heterogeneous group of symptoms representing i.a. deficits of motor coordination, sequencing of complex motor acts and sensory integration. CSS were introduced as group of the neurological deficits of posture, gait, kinetic functions, eye movements and speech, associated more specifically to cerebellar abnormalities than NSS. Studies show significant effect size variability of those symptoms in BD group suggesting the existence of differing subpopulations. The aim of our study was to evaluate the effect of BD type, stage and the history of psychotic symptoms (HoPS) on the severity of CSS and NSS as none of the previous studies had verified the role of those categories.

METHODS

This study involved 181 participants: 116 euthymic BD patients (66 BD I, 50 BD II) and 65 healthy controls (HC). CSS was assessed with the International Cooperative Ataxia Rating Scale and NSS with Neurological Evaluation Scale. Patients were divided into early and late stage of the disorder according to Kapczinski's criteria. Rater was blind to patients' stage, type and HoPS.

RESULTS

Staging was related to vast majority of CSS and NSS scores. HoPS was related to oculomotor deficits. The effect of BD type was the least significant. Late stage BD showed more severe CSS and NSS than HC in every measure. There were no differences between early stage BD and HC, apart of posture and gait disturbances. Except of sensory integration scores, late stage BD showed higher CSS and NSS rates than early stage patients.

CONCLUSION

In this hitherto the largest study of neurological abnormalities in BD we have shown significant role of staging in CSS and NSS severity. Progression criteria based on inter-episode psychosocial functioning may stand as unrecognised factor responsible for variability observed in previous studies evaluating neurological abnormalities in BD. Our study suggests that in clinical practice NSS and CSS may be potentially used as easy-to-assess biological marker of BD staging. Observed severity of neurological impairments of BD patients may more likely correspond to the disease progression than to BD type and HoPS.

Investigation of Genetic Variants Associated with Tryptophan Metabolite Levels via Serotonin and Kynurenine Pathways in Patients with Bipolar Disorder

The kynurenine pathway (KP) may play a role in the pathophysiology of bipolar disorder (BD). We conducted a genome-wide association study (GWAS) to identify genetic variants associated with the plasma levels of the metabolites of tryptophan (TRP) via the serotonin (5-HT) and kynurenine (KYN) pathways in 44 patients with BD and 45 healthy controls. We assessed whether variants that were differentially associated with metabolite levels based on the diagnostic status improved the prediction accuracy of BD using penalized regression approaches. We identified several genetic variants that were significantly associated with metabolites (5-HT, 5-hydroxytryptophan (5-HTP), TRP, and quinolinic acid (QA) or metabolite ratios (5-HTP/TRP and KYN/TRP) and for which the diagnostic status exerted a significant effect. The inclusion of genetic variants led to increased accuracy in the prediction of the BD diagnostic status. Specifically, we obtained an accuracy of 0.77 using Least Absolute Shrinkage and Selection Operator (LASSO) regression. The predictors retained as informative in this model included body mass index (BMI), the levels of TRP, QA, and 5-HT, the 5-HTP/TRP ratio, and genetic variants associated with the levels of QA (rs6827515, rs715692, rs425094, rs4645874, and rs77048355) and TRP (rs292212) or the 5-HTP/TRP ratio (rs7902231). In conclusion, our study identified statistically significant associations between metabolites of TRP via the 5-HT and KYN pathways and genetic variants at the genome-wide level. The discriminative performance of penalized regression models incorporating clinical, genetic, and metabolic predictors warrants a follow-up analysis of this panel of determinants.

Psychotic symptoms in bipolar disorder and their impact on the illness: A systematic review

BACKGROUND

Lifetime psychotic symptoms are present in over half of the patients with bipolar disorder (BD) and can have an adverse effect on its course, outcome, and treatment. However, despite a considerable amount of research, the impact of psychotic symptoms on BD remains unclear, and there are very few systematic reviews on the subject.

AIM

To examine the extent of psychotic symptoms in BD and their impact on several aspects of the illness.

METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines were followed. An electronic literature search of six English-language databases and a manual search was undertaken to identify published articles on psychotic symptoms in BD from January 1940 to December 2021. Combinations of the relevant Medical Subject Headings terms were used to search for these studies. Articles were selected after a screening phase, followed by a review of the full texts of the articles. Assessment of the methodological quality of the studies and the risk of bias was conducted using standard tools.

RESULTS

This systematic review included 339 studies of patients with BD. Lifetime psychosis was found in more than a half to two-thirds of the patients, while current psychosis was found in a little less than half of them. Delusions were more common than hallucinations in all phases of BD. About a third of the patients reported first-rank symptoms or mood-incongruent psychotic symptoms, particularly during manic episodes. Psychotic symptoms were more frequent in bipolar type I compared to bipolar type II disorder and in mania or mixed episodes compared to bipolar depression. Although psychotic symptoms were not more severe in BD, the severity of the illness in psychotic BD was consistently greater. Psychosis was usually associated with poor insight and a higher frequency of agitation, anxiety, and hostility but not with psychiatric comorbidity. Psychosis was consistently linked with increased rates and the duration of hospitalizations, switching among patients with depression, and poorer outcomes with mood-incongruent symptoms. In contrast, psychosis was less likely to be accompanied by a rapid-cycling course, longer illness duration, and heightened suicidal risk. There was no significant impact of psychosis on the other parameters of course and outcome.

CONCLUSION

Though psychotic symptoms are very common in BD, they are not always associated with an adverse impact on BD and its course and outcome.

Phenotypes, mechanisms and therapeutics: insights from bipolar disorder GWAS findings

Genome-wide association studies (GWAS) have reported substantial genomic loci significantly associated with clinical risk of bipolar disorder (BD), and studies combining techniques of genetics, neuroscience, neuroimaging, and pharmacology are believed to help tackle clinical problems (e.g., identifying novel therapeutic targets). However, translating findings of psychiatric genetics into biological mechanisms underlying BD pathogenesis remains less successful. Biological impacts of majority of BD GWAS risk loci are obscure, and the involvement of many GWAS risk genes in this illness is yet to be investigated. It is thus necessary to review the progress of applying BD GWAS risk genes in the research and intervention of the disorder. A comprehensive literature search found that a number of such risk genes had been investigated in cellular or animal models, even before they were highlighted in BD GWAS. Intriguingly, manipulation of many BD risk genes (e.g., ANK3, CACNA1C, CACNA1B, HOMER1, KCNB1, MCHR1, NCAN, SHANK2 etc.) resulted in altered murine behaviors largely restoring BD clinical manifestations, including mania-like symptoms such as hyperactivity, anxiolytic-like behavior, as well as antidepressant-like behavior, and these abnormalities could be attenuated by mood stabilizers. In addition to recapitulating phenotypic characteristics of BD, some GWAS risk genes further provided clues for the neurobiology of this illness, such as aberrant activation and functional connectivity of brain areas in the limbic system, and modulated dendritic spine morphogenesis as well as synaptic plasticity and transmission. Therefore, BD GWAS risk genes are undoubtedly pivotal resources for modeling this illness, and might be translational therapeutic targets in the future clinical management of BD. We discuss both promising prospects and cautions in utilizing the bulk of useful resources generated by GWAS studies. Systematic integrations of findings from genetic and neuroscience studies are called for to promote our understanding and intervention of BD.

Is there an association between inflammatory/anti-oxidant markers and the presence of psychotic symptoms or severity of illness in mood and psychotic disorders? A multi-centric study on a drug-free sample

The immune and antioxidant systems are intimately connected and their role in the etiology of major psychiatric disorders is currently under study. The aim of this study was to evaluate the potential associations between inflammatory/antioxidant peripheral markers and presence of psychotic symptoms or severity of illness in patients affected by major psychiatric disorders.

One hundred and twenty-six drug-free patients were included. A blood sample was collected to measure total/B/T lymphocytes and plasma levels of albumin, total bilirubin, uric acid, C-reactive protein, and vitamins A and E. Severity of illness was assessed using psychometric scales. Groups of patients divided according to diagnosis were compared in terms of measured markers using multivariate analyses of variance (MANOVAs). Linear and logistic regression analyses were performed to investigate the potential association between markers and severity of illness or presence/absence of psychotic symptoms.

Albumin plasma levels were higher in patients with substance-induced psychotic disorder (SIPD) than subjects affected by schizophrenia (F ​= ​4.923; p ​= ​0.003). Lower vitamin E (OR ​= ​0.81; p ​= ​0.014) and T lymphocyte (OR ​= ​0.99; p ​= ​0.048) plasma levels were predictive of lifetime psychotic symptoms. Lower vitamin A levels were associated with higher Montgomery-Åsberg Depression Rating Scale scores (β ​= ​-24.26; p ​= ​0.029), independent of diagnosis.

Patients with SIPD may be less vulnerable to oxidative stress. The severity of depressive symptoms, inversely associated with vitamin A plasma levels, is likely to be modulated by the degree of inflammation. Patients presenting with lifetime psychotic symptoms may be more vulnerable to oxidative stress and may have a higher activation of humoral immunity.

Screening Biomarkers and Constructing a Predictive Model for Symptomatic Urinary Tract Infection and Asymptomatic Bacteriuria in Patients Undergoing Cutaneous Ureterostomy: A Metagenomic Next-Generation Sequencing Study

Objectives. To investigate the clinical diagnostic value of differential flora as biomarkers in patients with symptomatic urinary tract infection (UTI) and asymptomatic bacteriuria (ASB) undergoing cutaneous ureterostomy based on metagenomic next-generation sequencing and construct predictive models to provide a scientific reference for clinical diagnosis and treatment. Material and Methods. According to standard procedures, samples were taken from each patient for routine tests (urine, ureteral stent, and skin swab around the stoma). Cytokine levels in the blood were also detected. Urinary microflora were measured by mNGS, and potential biomarkers for distinguishing UTI and ASB were identified by differential flora. Finally, we generated the predictive models for ASB and UTI using the Lasso method and cytokine levels. Results. Urine culture was performed for 50 patients with cutaneous ureterostomy; 44 of these patients developed bacteriuria. The incidence of symptomatic bacteriuria was 54.55%. Biomarker analysis showed that Propionimicrobium lymphophilum, Staphylococcus haemolyticus, Stenotrophomonas maltophilia, Ralstonia insidiosa, and Aspergillus sydowii all had good predictive performance and were combined in a single model. The predictive model exhibited good prediction performance (area under the curve $\left(\text{AUC}\right)=0.8729$ , $\text{sensitivity}=80\%$ , $\text{specificity}=83.3\%$ , and $\text{cutoff}=1.855$ ). We also identified a significant negative correlation between the weight sum of the abundance for these five characteristic pathogens (Sum_weighted_Reads) and levels of the cytokine IL-6 and IL-1β ( $P<0.05$ ). Conclusion. mNGS had a higher positive detection rate for pathogens in urine samples. The selected differential bacteria can be used as biomarkers of ASB and UTI, and the prediction model has good predictive performance. Analysis also showed that the occurrence of symptoms was related to individual immunity. Combined with the Sum_weighted_Reads cutoff and cytokine levels (IL-6 and IL-1β) of differential flora, it was possible to judge the severity of symptoms in cutaneous ureterostomy patients with bacteriuria and provide new insights for the treatment and intervention of ASB and UTI.

Cortisol to Dehydroepiandrosterone Sulphate Ratio and Executive Function in Bipolar Disorder

INTRODUCTION

Bipolar disorder (BD) is associated with impairment in cognitive domains such as verbal memory and executive functions. Very few studies have assessed dehydroepiandrosterone sulphate (DHEA-S) in BD and its relation to cognitive functioning despite evidence showing its regulatory effects on glucocorticoid action. The aim of our study was to explore the association of cortisol, DHEA-S, and cortisol to DHEA-S ratio with visuospatial memory and executive functioning in BD.

METHODS

Cognitive performance of 60 bipolar I patients and 30 healthy subjects was evaluated by using Cambridge Neuropsychological Test Automated Battery tasks targeting visuospatial memory (spatial recognition memory) and executive functions (planning [Stockings of Cambridge; SOC] and attentional set shifting [ID/ED]). Morning serum cortisol and DHEA-S levels were measured in patients. Main effects of cortisol, DHEA-S, and cortisol/DHEA-S ratio for each neurocognitive task were explored in multiple regression analyses correcting for demographic and clinical parameters as well as treatment-related factors (current use of antipsychotic and mood stabilizer medication).

RESULTS

Bipolar patients showed poorer performance than healthy subjects in planning and attentional set shifting but not in visuospatial memory. Cortisol to DHEA-S ratio predicted worse performance in planning (SOC).

CONCLUSIONS

This is the first study to assess memory and executive function in BD in relation to DHEA-S and cortisol to DHEA-S ratio. We report an association of cortisol to DHEA-S ratio with worse performance in planning in bipolar I patients, which warrants further investigation.

Analysis of Seasonal Clinical Characteristics in Patients With Bipolar or Unipolar Depression

This study was to investigate the characteristics of seasonal symptoms and non-enzymatic oxidative stress in the first hospitalized patients with bipolar and unipolar depression, aiming to differentiate bipolar depression from unipolar depression and reduce their misdiagnosis. A total of 450 patients with bipolar depression and 855 patients with depression were included in the present study. According to the season when the patients were admitted to the hospital due to the acute onset of depression, they were further divided into spring, summer, autumn and winter groups. According to the characteristics of symptoms of bipolar disorder in the DSM-5, the characteristic symptoms of bipolar disorder were collected from the medical record information, and clinical biochemical indicators that can reflect the oxidative stress were also recorded. The seasonal risk factors in patients with bipolar or unipolar depression were analyzed. The relationship of age and gender with the bipolar or unipolar depression which attacked in winter was explored. There were significant differences between groups in the melancholic features, atypical features and conjugated bilirubin in spring. In summer, there were significant differences between groups in the melancholic features, uric acid and conjugated bilirubin. In autumn, there were marked differences between groups in melancholic features, anxiety and pain, atypical features, uric acid, total bilirubin, conjugated bilirubin and albumin. In winter, the conjugated bilirubin and prealbumin were significantly different between two groups. The melancholic features and uric acid that in summer as well as melancholic features, uric acid and total bilirubin in autumn were the seasonal independent risk factors for the unipolar depression as compared to bipolar depression. In winter, significant difference was noted in the age between two groups. In conclusion, compared with patients with unipolar depression, patients with bipolar depression have seasonal characteristics. Clinical symptoms and indicators of oxidative stress may become factors for the differentiation of seasonal unipolar depression from bipolar depression. Young subjects aged 15-35 years are more likely to develop bipolar depression in winter.

Altered spatiotemporal consistency in pediatric bipolar disorder patients with and without psychotic symptoms

OBJECTIVE

Psychotic symptoms are quite common in patients with pediatric bipolar disorder (PBD) and may affect the symptom severity and prognosis of PBD. However, the potential mechanisms are less well elucidated until now. Thus, the purpose of this study was to investigate the brain functional differences between PBD patients with and without psychotic symptoms.

METHOD

A total of 71 individuals including: 27 psychotic PBD (P-PBD), 25 nonpsychotic PBD (NP-PBD), and 19 healthy controls were recruited in the present study. Each subject underwent 3.0 Tesla functional magnetic resonance imaging scan. Four-dimensional (spatiotemporal) Consistency of local neural Activities (FOCA) was employed to detect the local brain activity changes. Analyses of variance (ANOVA) were used to reveal brain regions with significant differences among three groups groups of individuals, and inter-group comparisons were assessed using post hoc tests.

RESULTS

The ANOVA obtained significant among-group FOCA differences in the left triangular inferior frontal gyrus, left supplementary motor area, left precentral gyrus, right postcentral gyrus, right superior occipital gyrus, and right superior frontal gyrus. Compared with the control group, the P-PBD group showed decreased FOCA in the left supplementary motor area and bilateral superior frontal gyrus and showed increased FOCA in the left triangular inferior frontal gyrus. In contrast, the NP-PBD group exhibited decreased FOCA in the right superior occipital gyrus and right postcentral gyrus and showed increased FOCA in the left orbital inferior frontal gyrus. Compared to the NP-PBD group, the P-PBD group showed decreased FOCA in the right superior frontal gyrus.

CONCLUSION

The present findings demonstrated that the two groups of PBD patients exhibited segregated brain functional patterns, providing empirical evidence for the biological basis of different clinical outcomes between PBD patients with and without psychotic symptoms.

A system biology approach based on metabolic biomarkers and protein-protein interactions for identifying pathways underlying schizophrenia and bipolar disorder

Mental disorders (MDs), including schizophrenia (SCZ) and bipolar disorder (BD), have attracted special attention from scientists due to their high prevalence and significantly debilitating clinical features. The diagnosis of MDs is still essentially based on clinical interviews, and intensive efforts to introduce biochemical based diagnostic methods have faced several difficulties for implementation in clinics, due to the complexity and still limited knowledge in MDs. In this context, aiming for improving the knowledge in etiology and pathophysiology, many authors have reported several alterations in metabolites in MDs and other brain diseases. After potentially fishing all metabolite biomarkers reported up to now for SCZ and BD, we investigated here the proteins related to these metabolites in order to construct a protein-protein interaction (PPI) network associated with these diseases. We determined the statistically significant clusters in this PPI network and, based on these clusters, we identified 28 significant pathways for SCZ and BDs that essentially compose three groups representing three major systems, namely stress response, energy and neuron systems. By characterizing new pathways with potential to innovate the diagnosis and treatment of psychiatric diseases, the present data may also contribute to the proposal of new intervention for the treatment of still unmet aspects in MDs.

Sex hormones and immune system: A possible interplay in affective disorders? A systematic review

BACKGROUND

Sex hormones and the immune system may play a key role in sex differences in affective disorders. The understanding of their interplay may lead to the detection of new sex-specific tailored therapeutic approaches. The aim of this systematic review is to summarise the evidence supporting a possible association between sex hormones and inflammatory biomarkers in people with affective disorders.

METHODS

A systematic search of the literature published until January 2021 was conducted on PubMed database. The initial search identified a total of 1259 studies; 20 studies investigating inflammatory biomarkers and sex hormones in patients exhibiting depressive symptoms were included: 10 studies focused on patients with affective disorders, and 10 studies focused on women in menopause or in the post-partum period exhibiting depressive symptoms.

RESULTS

Testosterone and exogenous female sex hormones may play protective roles through their modulation of the immune system, respectively, in male patients with bipolar disorder and in peri-/post-menopausal women with depression.

LIMITATIONS

The main limitations are the paucity of studies investigating both sex hormones and immune biomarkers, the lack of statistical analyses exploring specifically the association between these two classes of biomarkers, and the great heterogeneity between the participants' samples in the studies.

CONCLUSION

This review highlights the need to investigate the interplay between sex hormones and immune system in affective disorders. The inconsistent or incomplete evidence may be improved by studies in patients with moderate-high inflammatory levels that specifically evaluate the relationship between sex hormones and the immune system.

Brain structural alterations in pediatric bipolar disorder patients with and without psychotic symptoms

BACKGROUND

Bipolar disorder (BD) with psychotic symptoms is a specific phenotype that presents greater risk of relapse and worse outcomes than nonpsychotic BD, however, the underlying mechanisms remain unknown and are less revealed in youth. Thus, the aims of the present study were to investigate brain structural alterations in pediatric bipolar disorder (PBD) patients with and without psychotic symptoms, and specifically to evaluate the impact of psychotic features on gray matter volume (GMV) in PBD patients.

METHOD

A total of 73 individuals were recruited into three groups, n = 28, psychotic PBD, P-PBD; n = 26, nonpsychotic PBD, NP-PBD; and n = 19, healthy controls, HC. All participants underwent high-resolution structural magnetic resonance scans. Voxel-based morphometry was used to investigate GMV alterations. Analyses of variance (ANOVA) were performed to obtain brain regions with significant differences among three groups and then post hoc tests were calculated for inter-group comparisons.

RESULTS

The ANOVA revealed significant GMV differences among three groups in the bilateral amygdala-hippocampus-parahippocampal complex (AMY-HIS-ParaHIS complex), left superior temporal gyrus (STG), left inferior frontal gyrus (IFG), bilateral putamen (PUT), left precentral gyrus (PG), left supramarginal gyrus (SMG), and right inferior parietal lobule (IPL). Compared with HCs, P-PBD patients showed decreased GMV in the bilateral AMY-HIS-ParaHIS complex, left STG, left IFG, bilateral PUT, and left PG; while NP-PBD patients exhibited decreased GMV in the left IFG, left PG, left SMG, and right IPL. Furthermore, P-PBD patients showed increased GMV in the right IPL when comparing to NP-PBD patients.

LIMITATION

The present findings require replication in larger samples and verification in medication free subjects.

CONCLUSION

The present findings suggested that psychotic features in PBD were associated with extensive brain structural lesions mainly located in the prefrontal-limbic-striatum circuit, which might represent the pathological basis of more sever symptoms in patients with psychotic PBD.

Brain activation during verbal fluency task in type II bipolar disorder patients: a near-infrared spectroscopy study

BACKGROUND

Previous studies have shown that BD patients exhibited impairment when performing a verbal fluency task (VFT) and abnormal prefrontal cortex activation during this task. However, no study has specifically examined whether patients with type II BD demonstrate difficulty in performing VFT and impairments in relevant neural correlates or whether these are related to psychotic symptoms, the present study aimed to examine these issues.

METHODS

Forty-nine patients with type II BD (21 patients with psychotic symptoms [BDIIp] and 28 patients without psychotic symptoms [BDIIn]) and 45 matched healthy controls (HCs) participated the study and completed the VFTs, while their brain activity was recorded with near-infrared spectroscopy (NIRS).

RESULTS

Both BDIIp and BDIIn patients showed poorer performance on VFTs than HCs. In addition, BDII patients showed lower brain activation than HCs in bilateral dorsolateral prefrontal cortex and right frontal pole, these results were mainly driven by BDIIn patients. Moreover, subjective psychotic symptoms were positively significantly correlated with left dorsolateral prefrontal cortex activation in BDII patients.

CONCLUSIONS

Type II BD patients showed significant impairment when performing VFTs and reduced activation in the prefrontal cortex, and subjective psychotic symptoms were associated with brain activation in left dorsolateral prefrontal cortex in BDII patients.

A miRNome analysis of drug-free manic psychotic bipolar patients versus healthy controls

The lifetime presence of psychotic symptoms is associated with more clinical severity, poorer outcome and biological changes in patients affected by bipolar disorder (BD). Epigenetic mechanisms have been evoked to explain the onset of psychotic symptoms in BD as well as the associated biological changes. The main objective of the present study was to evaluate the expression profiles of circulating microRNAs (miRNAs) in drug-free manic psychotic bipolar patients versus healthy controls (HC), to identify possible non-invasive molecular markers of the disorder. 15 drug-free manic psychotic bipolar patients and 9 HC were enrolled and 800 miRNAs expression profile was measured by Nanostring nCounter technology on plasma samples and validated through qPCR. Overall, twelve miRNAs showed a significantly altered expression between the two groups (p < 0.05). Functional annotation of predicted miRNAs targets by MultiMIR R tool showed repression in bipolar patients of genes with a role in neurodevelopment and neurogenesis, and upregulation of genes involved in metabolism regulation. We identified a signature of circulating miRNA characteristic of manic psychotic bipolar patients, suggesting a possible role in neurodevelopment and metabolic processes regulation.

Human Genomic Signatures of Brain Oscillations During Memory Encoding

Memory encoding is an essential step for all learning. However, the genetic and molecular mechanisms underlying human memory encoding remain poorly understood, and how this molecular framework permits the emergence of specific patterns of brain oscillations observed during mnemonic processing is unknown. Here, we directly compare intracranial electroencephalography recordings from the neocortex in individuals performing an episodic memory task with human gene expression from the same areas. We identify genes correlated with oscillatory memory effects across 6 frequency bands. These genes are enriched for autism-related genes and have preferential expression in neurons, in particular genes encoding synaptic proteins and ion channels, supporting the idea that the genes regulating voltage gradients are involved in the modulation of oscillatory patterns during successful memory encoding across brain areas. Memory-related genes are distinct from those correlated with other forms of cognitive processing and resting state fMRI. These data are the first to identify correlations between gene expression and active human brain states as well as provide a molecular window into memory encoding oscillations in the human brain.

Psychotic versus non-psychotic bipolar disorder: Socio-demographic and clinical profiles in an Italian nationwide study

OBJECTIVE

Psychotic versus non-psychotic patients with bipolar disorder have been traditionally associated with different unfavorable clinical features. In this study on bipolar Italian patients, we aimed to compare clinical and demographic differences between psychotic and non-psychotic individuals, exploring clinical factors that may favor early diagnosis and personalized treatment.

METHODS

A total of 1671 patients (males: n = 712 and females: n = 959; bipolar type 1: n = 1038 and bipolar type 2: n = 633) from different psychiatric departments were compared according to the lifetime presence of psychotic symptoms in terms of socio-demographic and clinical variables. Chi-square tests for qualitative variables and Student's t-tests for quantitative variables were performed for group comparison, and a multivariable logistic regression was performed, considering the lifetime psychotic symptoms as dependent variables and socio-demographic/clinical characteristics as independent variables.

RESULTS

Psychotic versus non-psychotic bipolar subjects resulted to: be more frequently unemployed (p < 0.01) and never married/partnered (p < 0.01); have an earlier age at onset (p < 0.01); more frequently receive a first diagnosis different from a mood disorder (p < 0.01); have a shorter duration of untreated illness (p < 0.01); have a more frequently hypomanic/manic prevalent polarity (p < 0.01) and a prevalent manic-depressive type of cycling (p < 0.01); present a lower lifetime number of depressive episodes (p < 0.01), but have more manic episodes (p < 0.01); and less insight (p < 0.01) and more hospitalizations in the last year (p < 0.01). Multivariable regression analysis showed that psychotic versus non-psychotic bipolar patients received more frequently a first diagnosis different from bipolar disorder (odds ratio = 0.64, 95% confidence interval = [0.46, 0.90], p = 0.02) or major depressive disorder (odds ratio = 0.66, 95% confidence interval = [0.48, 0.91], p = 0.02), had more frequently a prevalent manic polarity (odds ratio = 1.84, 95% confidence interval = [1.14, 2.98], p < 0.01) and had a higher number of lifetime manic episodes (more than six) (odds ratio = 8.79, 95% confidence interval = [5.93, 13.05], p < 0.01).

CONCLUSION

Lifetime psychotic symptoms in bipolar disorder are associated with unfavorable socio-demographic and clinical features as well as with a more frequent initial misdiagnosis.

Associations of the serotonin transporter promoter polymorphism (5-HTTLPR) with bipolar disorder and treatment response: A systematic review and meta-analysis

BACKGROUND

Associations of the serotonin transporter promoter polymorphism (5-HTTLPR) with bipolar disorder (BPD) and treatment response in bipolar patients were not conclusive. This study not only assessed the association between the 5-HTTLPR and BPD with accumulating relevant studies, but also in the first time evaluated the effect of the 5-HTTLPR on both anti-depressive and anti-manic treatment responses in bipolar patients.

METHODS

PubMed, Embase, PsycINFO, Cochrane Library and Cochrane Control Trials databases were systematically searched before February 2017. This meta-analysis followed the PRISMA guidelines.

RESULTS

A total of 32 population-based studies (5567 cases and 6993 controls) and 9 family-based studies (837 trios) were finally screened out and statistically joined into a single meta-analysis that revealed an association between S allele and an increased risk of BPD (OR = 1.06, p = .038). Pooled analysis of the 32 population-based studies indicated an association of S-carrier genotypes with an increased risk of BPD (OR = 1.10, p = .029). Meanwhile, the association remained significant in Caucasians (OR = 1.15, p = .004), which could provide an enough power (88%) to detect a significant association. Regarding the treatment response studies, 6 studies reporting the relationship of the 5-HTTLPR in anti-depressive remission rate (1034 patients) and 7 studies reporting in response rate (1098 patients) were included for pooled analyses. We observed a significant association of S-carrier genotypes with a reduced anti-depressive remission rate (OR = 0.64, p = .006) but not with anti-depressive response rate. The association between the 5-HTTLPR with anti-manic response rate was not observed in the included 6 studies (676 patients).

CONCLUSIONS

The present study supported the presence of a marginal but detectable effect of the 5-HTTLPR on susceptibility to BPD. Moreover, the detected association in Caucasian was statistically reliable. Besides, the 5-HTTLPR was identified as a useful predictor for anti-depressive remission but not for anti-depressive or anti-manic response.

Neurocognition and functional outcome in patients with psychotic, non-psychotic bipolar I disorder, and schizophrenia. A five-year follow-up

Background:

Bipolar disorder (BD) and schizophrenia (SZ) are characterized by neurocognitive and functional deficits with marked heterogeneity. It has been suggested that BD with a history of psychotic symptoms (BD-P) could constitute a phenotypically homogeneous subtype characterized by greater neurocognitive and functional impairments, or by a distinct trajectory of such deficits. The aim of this study was to compare the neurocognitive and functional course of euthymic BD-P, euthymic BD patients without a history of psychosis (BD-NP), stabilized patients with schizophrenia and healthy subjects, during a five-year follow-up.

Methods:

Neurocognitive and psychosocial function was examined in 100 euthymic patients with BD (50 BD-P, 50 BD-NP), 50 stabilized patients with schizophrenia (SZ), and 51 healthy controls (HC) at baseline (T1), and after a 5-year follow-up (T2).

Results:

The course of both neurocognitive performance and functional outcome of patients with SZ and BD (BD-P and BD-NP) is stable. The profile of neurocognitive impairment of patients with SZ or BD (BD-P and BD-NP), is similar, with only quantitative differences circumscribed to certain domains, such as working memory. The subgroup of patients with BD-NP does not show functional deterioration.

Conclusions:

We have not found evidence of progression in the neurocognitive or psychosocial impairment in any of the three groups of patients, although it cannot be dismissed the possibility of a subset of patients with a progressive course. Other longitudinal studies with larger samples and longer duration are necessary to confirm these findings.

Gray matter bases of psychotic features in adult bipolar disorder: A systematic review and voxel-based meta-analysis of neuroimaging studies

Psychotic bipolar disorder (P-BD) is a specific subset that presents greater risk of relapse and worse outcomes than nonpsychotic bipolar disorder (NP-BD). To explore the neuroanatomical bases of psychotic dimension in bipolar disorder (BD), a systematic review was carried out based on the gray matter volume (GMV) among P-BD and NP-BD patients and healthy controls (HC). Further, we conducted a meta-analysis of GMV differences between P-BD patients and HC using a whole-brain imaging approach. Our review revealed that P-BD patients exhibited smaller GMVs mainly in the prefronto-temporal and cingulate cortices, the precentral gyrus, and insula relative to HC both qualitatively and quantitatively. Qualitatively the comparison between P-BD and NP-BD patients suggested inconsistent GMV alterations mainly involving the prefrontal cortex, while NP-BD patients showed GMV deficits in local regions compared with HC. The higher proportions of female patients and patients taking psychotropic medication in P-BD and P-BD type I were associated with smaller GMV in the right precentral gyrus, and the right insula, respectively. In conclusions, psychosis in BD might be associated with specific cortical GMV deficits. Gender and psychotropic medication might have effects on the regional GMVs in P-BD patients. It is necessary to distinguish psychotic dimension in neuroimaging studies of BD.

Mechanisms of Action of Dehydroepiandrosterone

Dehydroepiandrosterone (3β-hydroxy-5-androsten-17-one, DHEA) and its sulfated metabolite DHEA-S are the most abundant steroids in circulation and decline with age. Rodent studies have shown that DHEA has a wide variety of effects on liver, kidney, adipose, reproductive tissues, and central nervous system/neuronal function. The mechanisms by which DHEA and DHEA-S impart their physiological effects may be direct actions on plasma membrane receptors, including a DHEA-specific, G-protein-coupled receptor in endothelial cells; various neuroreceptors, e.g., aminobutyric-acid-type A, N-methyl-d-aspartate (NMDA), and sigma-1 (S1R) receptors; by binding steroid receptors: androgen and estrogen receptors (ARs, ERα, or ERβ); or by their metabolism to more potent sex steroid hormones, e.g., testosterone, dihydrotestosterone, and estradiol, which bind with higher affinity to ARs and ERs. DHEA inhibits voltage-gated T-type calcium channels. DHEA activates peroxisome proliferator-activated receptor (PPARα) and CAR by a mechanism apparently involving PP2A, a protein phosphatase dephosphorylating PPARα and CAR to activate their transcriptional activity. We review our recent study showing DHEA activated GPER1 (G-protein-coupled estrogen receptor 1) in HepG2 cells to stimulate miR-21 transcription. This chapter reviews some of the physiological, biochemical, and molecular mechanisms of DHEA and DHEA-S activity.

Genome-wide association studies of bipolar disorder: A systematic review of recent findings and their clinical implications

Recent advances in molecular genetics have enabled assessments of the associations among genetic variants (e.g., single-nucleotide polymorphisms) and susceptibility for complex diseases, including psychiatric disorders. Specifically, genome-wide association studies (GWAS), meta-analyses of the GWAS summary statistics, and mega-analyses (which use raw data, not summary statistics) of GWAS have provided revolutionary results and have identified numerous susceptibility genes or single-nucleotide polymorphisms. By using several tens of thousands of subjects, >40 genes have been identified as being associated with susceptibility for bipolar disorder so far. The purpose of this systematic review was to summarize the recent findings of bipolar disorder GWAS and discuss their clinical implications.

Biological aspects and candidate biomarkers for rapid-cycling in bipolar disorder: A systematic review

Rapid-cycling bipolar disorder represents a frequent severe subtype of illness which has been associated with poor response to pharmacological treatment. Aim of the present article is to provide an updated review of biological markers associated with rapid-cycling bipolar disorder. A research in the main database sources has been conducted to identify relevant papers about the topic. Rapid-cycling bipolar disorder patients seem to have a more frequent family history for bipolar spectrum disorders (d range: 0.44-0.74) as well as an increased susceptibility to DNA damage or mRNA hypo-transcription (d range: 0.78-1.67) than non rapid-cycling ones. A susceptibility to hypothyroidism, which is exacerbated by treatment with lithium, is possible in rapid-cycling bipolar disorder, but further studies are needed to draw definitive conclusions. Rapid-cycling bipolar patients might have more insuline resistance as well as more severe brain changes in frontal areas (d range: 0.82-0.94) than non rapid-cycling ones. Many questions are still open about this topic. The first is whether the rapid-cycling is inheritable or is more generally the manifestation of a severe form of bipolar disorder. The second is whether some endocrine dysfunctions (diabetes and hypothyroidism) predispose to rapid-cycling or rapid-cycling is the consequence of drug treatment or medical comorbidities (e.g. obesity).

Neurocognition in patients with psychotic and non-psychotic bipolar I disorder. A comparative study with individuals with schizophrenia

BACKGROUND

It has been suggested that patients with bipolar disorder with psychotic symptoms (BD-P) have larger neurocognitive impairment than patients with bipolar disorder without a history of psychotic symptoms (BD-NP). The objective of this study was to compare neurocognitive performance of BD-P and BD-NP relative to a group of patients with schizophrenia (SZ), and healthy controls (HC).

METHODS

Neurocognitive function was examined in 100 subjects with bipolar I disorder (50 BD-P, 50 BD-NP), 50 SZ, and 51 HC. All patients with BD fulfilled criteria for euthymia, while all SZ patients were stabilised for at least the previous 3 months.

RESULTS

Patients with BD-P and BD-NP performed worse than HC in all neurocognitive measures, except for sustained attention. Differences between BD-P and BD-NP were subtle and circumscribed to the working memory domain (effect size: 0.29). SZ performed worse than BD-NP in the neurocognitive composite index (NCI) and in the working memory domain. There were no differences between SZ and BD-P in any neurocognitive measure.

LIMITATIONS

The relatively small sample size, the cross-sectional design and, that patients were receiving pharmacological treatment are the main limitations of this study.

CONCLUSIONS

Our findings show that the three groups of patients have a large neurocognitive impairment. Differences are quantitative and only present in some neurocognitive domains, such as working memory. These results suggest that patients with BD and SZ can benefit from the same strategies of cognitive remediation.

Plasma Nervonic Acid Is a Potential Biomarker for Major Depressive Disorder: A Pilot Study

BACKGROUND

Diagnostic biomarkers of major depressive disorder, bipolar disorder, and schizophrenia are urgently needed, because none are currently available.

METHODS

We performed a comprehensive metabolome analysis of plasma samples from drug-free patients with major depressive disorder (n=9), bipolar disorder (n=6), schizophrenia (n=17), and matched healthy controls (n=19) (cohort 1) using liquid chromatography time-of-flight mass spectrometry. A significant effect of diagnosis was found for 2 metabolites: nervonic acid and cortisone, with nervonic acid being the most significantly altered. The reproducibility of the results and effects of psychotropic medication on nervonic acid were verified in cohort 2, an independent sample set of medicated patients [major depressive disorder (n=45), bipolar disorder (n=71), schizophrenia (n=115)], and controls (n=90) using gas chromatography time-of-flight mass spectrometry.

RESULTS

The increased levels of nervonic acid in patients with major depressive disorder compared with controls and patients with bipolar disorder in cohort 1 were replicated in the independent sample set (cohort 2). In cohort 2, plasma nervonic acid levels were also increased in the patients with major depressive disorder compared with the patients with schizophrenia. In cohort 2, nervonic acid levels were increased in the depressive state in patients with major depressive disorder compared with the levels in the remission state in patients with major depressive disorder and the depressive state in patients with bipolar disorder.

CONCLUSION

These results suggested that plasma nervonic acid is a good candidate biomarker for the depressive state of major depressive disorder.

Infectious and immunogenetic factors in bipolar disorder

OBJECTIVE

Despite the evidence supporting the association between infection and bipolar disorder (BD), the genetic vulnerability that mediates its effects has yet to be clarified. A genetic origin for the immune imbalance observed in BD, possibly involved in the mechanisms of pathogen escape, has, however, been suggested in recent studies.

METHOD

Here, we present a critical review based on a systematic literature search of articles published until December 2016 on the association between BD and infectious/immunogenetic factors.

RESULTS

We provide evidence suggesting that infectious insults could act as triggers of maladaptive immune responses in BD and that immunogenetic vulnerability may amplify the effects of such environmental risk factors, increasing susceptibility to subsequent environmental encounters. Quality of evidence was generally impaired by scarce attempt of replication, small sample sizes and lack of high-quality environmental measures.

CONCLUSION

Infection has emerged as a potential preventable cause of morbidity in BD, urging the need to better investigate components of the host-pathogen interaction in patients and at-risk subjects, and thus opening the way to novel therapeutic opportunities.

Clinical Phenotype of Depression Affects Interleukin-6 Synthesis

Major depressive disorder (MDD) is not a single disease, but a number of various ailments that form one entity. Psychomotor retardation, anhedonia, sleep disorders, an increased suicide risk, and anxiety are the main symptoms that often define the clinical diagnosis of depression. Interleukin-6 (IL-6), as one of the proinflammatory cytokines, seems to be overexpressed during certain mental disorders, including MDD. Overexpression of IL-6 in depression is thought to be a factor associated with bad prognosis and worse disease course. IL-6 may directly affect brain functioning and production of neurotransmitters; moreover, its concentration is correlated with certain clinical symptoms within the wide range of depressive symptomatology. Furthermore, there is a strong correlation between IL-6 synthesis and psychosomatic functioning of the patient. This article discusses potential sources and significance of IL-6 in the pathogenesis of depression.

Biological hypotheses and biomarkers of bipolar disorder

The most common mood disorders are major depressive disorders and bipolar disorders (BD). The pathophysiology of BD is complex, multifactorial, and not fully understood. Creation of new hypotheses in the field gives impetus for studies and for finding new biomarkers for BD. Conversely, new biomarkers facilitate not only diagnosis of a disorder and monitoring of biological effects of treatment, but also formulation of new hypotheses about the causes and pathophysiology of the BD. BD is characterized by multiple associations between disturbed brain development, neuroplasticity, and chronobiology, caused by: genetic and environmental factors; defects in apoptotic, immune-inflammatory, neurotransmitter, neurotrophin, and calcium-signaling pathways; oxidative and nitrosative stress; cellular bioenergetics; and membrane or vesicular transport. Current biological hypotheses of BD are summarized, including related pathophysiological processes and key biomarkers, which have been associated with changes in genetics, systems of neurotransmitter and neurotrophic factors, neuroinflammation, autoimmunity, cytokines, stress axis activity, chronobiology, oxidative stress, and mitochondrial dysfunctions. Here we also discuss the therapeutic hypotheses and mechanisms of the switch between depressive and manic state.

Search for plasma biomarkers in drug-free patients with bipolar disorder and schizophrenia using metabolome analysis

AIM

There is an urgent need for diagnostic biomarkers of bipolar disorder (BD) and schizophrenia (SZ); however, confounding effects of medication hamper biomarker discovery. In this study, we conducted metabolome analyses to identify novel plasma biomarkers in drug-free patients with BD and SZ.

METHODS

We comprehensively analyzed plasma metabolites using capillary electrophoresis time-of-flight mass spectrometry in patients with SZ (n = 17), BD (n = 6), and major depressive disorder (n = 9) who had not received psychotropics for at least 2 weeks, and in matched healthy controls (n = 19). The results were compared with previous reports, or verified in an independent sample set using an alternative analytical approach.

RESULTS

Lower creatine level and higher 2-hydroxybutyric acid level were observed in SZ than in controls (uncorrected P = 0.016 and 0.043, respectively), whereas they were unaltered in a previously reported dataset. Citrulline was nominally significantly decreased in BD compared to controls (uncorrected P = 0.043); however, this finding was not replicated in an independent sample set of medicated patients with BD. N-methyl-norsalsolinol, a metabolite of dopamine, was suggested as a candidate biomarker of BD; however, it was not detected by the other analytical method. Levels of betaine, a previously reported candidate biomarker of schizophrenia, were unchanged in the current dataset.

CONCLUSION

Our preliminary findings suggest that the effect of confounding factors, such as duration of illness and medication, should be carefully controlled when searching for plasma biomarkers. Further studies are required to establish robust biomarkers for these disorders.

The serotonin transporter gene 5-HTTLPR polymorphism is associated with affective psychoses but not with schizophrenia: A large-scale study in the Russian population

BACKGROUND

Affective syndrome is thought to be a key feature that differentiates schizophrenia from schizoaffective disorder (SA) and bipolar disorder with psychotic features (BDP). However genetic underpinnings of these differences remain unresolved.

OBJECTIVES

We compared clinical variables of affective psychoses (SA, BDP and schizophrenia with affective symptoms (AFF SCZ)) and schizophrenia without affective symptoms (non-AFF SCZ) and searched for a genetic variant that may differentiate affective psychosis from non-AFF SCZ.

METHODS

A total of 2677 subjects, including 831 patients with affective psychosis, 785 patients with non-AFF SCZ and 1061 healthy controls, were used. Clinical symptoms were assessed with the PANSS. The sample was genotyped for 5-HTTLPR polymorphism of the serotonin transporter gene.

RESULTS

The diagnostic groups differed significantly on demographic and clinical variables. The percentage of men was higher, the current age and age at illness onset were lower in non-AFF SCZ and SA compared to AFF SCZ and BDP. The severity of positive and negative symptoms decreased significantly from group to group in the following manner: non-AFF SCZ>AFF SCZ>SA>BDP. There was the association between 5-HTTLPR polymorphism and affective psychosis (p=0.01). The frequency of the SS genotype was higher in the affective psychosis group compared to non-AFF SCZ and controls. No differences in the genotype distribution were identified between the non-AFF SCZ group and controls.

LIMITATIONS

Difficulties in the differentiation between non-AFF SCZ and AFF SCZ or SA and between AFF SCZ and SA due to uncertain diagnostic boundaries between these conditions.

CONCLUSIONS

SA is intermediate between non-AFF SCZ and BDP in the severity of positive and negative symptoms. The first episode patients, carriers of the SS genotype have a higher risk of developing affective psychosis than non-AFF SCZ. This finding carries implications for the prognosis of psychosis outcomes in the first-episode patients.

Neurocognitive performance, psychopathology and social functioning in individuals at high risk for schizophrenia or psychotic bipolar disorder

INTRODUCTION

Although cognitive deficits are consistent endophenotypes of schizophrenia and bipolar disorder, findings in psychotic bipolar disorder (BDP) are inconsistent. In this study we compared adult unaffected first-degree relatives of schizophrenia and BDP patients on cognition, psychopathology, social functioning and quality of life.

METHODS

Sixty-six unaffected first-degree relatives of schizophrenia patients (SUnR), 36 unaffected first-degree relatives of BDP patients (BDPUnR) and 102 controls participated in the study. Between-group differences were examined and Discriminant Function Analysis (DFA) predicted group membership.

RESULTS

Visual memory, control inhibition, working memory, cognitive flexibility and abstract reasoning were linearly impaired in the relatives' groups. Poorer verbal fluency and processing speed were evident only in the SUnR group. The SUnR group had higher depressive and somatization symptoms while the BDPUnR group had higher anxiety and lower social functioning compared with the controls. Individuals with superior cognition were more likely to be classified as controls; those with higher social functioning, prolonged processing speed and lower anxiety were more likely to be classified as SUnR.

LIMITATIONS

The relatives' sample is quite heterogeneous; the effects of genetic or environmental risk-factors were not examined.

CONCLUSIONS

Cognitive functions mediated by a fronto-parietal network, show linear impairments in unaffected relatives of BDP and schizophrenia patients; processing speed and verbal fluency impairments were evident only in schizophrenia relatives. Self-perceived symptomatology and social functioning also differ between schizophrenia and BDP relatives. The continuum seen in patients in several indices was also seen in the cognitive impairments in unaffected relatives of schizophrenia and BDP patients.

Gene expression-based biological test for major depressive disorder: an advanced study

PURPOSE

Recently, we could distinguished patients with major depressive disorder (MDD) from nonpsychiatric controls with high accuracy using a panel of five gene expression markers (ARHGAP24, HDAC5, PDGFC, PRNP, and SLC6A4) in leukocyte. In the present study, we examined whether this biological test is able to discriminate patients with MDD from those without MDD, including those with schizophrenia and bipolar disorder.

PATIENTS AND METHODS

We measured messenger ribonucleic acid expression levels of the aforementioned five genes in peripheral leukocytes in 17 patients with schizophrenia and 36 patients with bipolar disorder using quantitative real-time polymerase chain reaction (PCR), and we combined these expression data with our previous expression data of 25 patients with MDD and 25 controls. Subsequently, a linear discriminant function was developed for use in discriminating between patients with MDD and without MDD.

RESULTS

This expression panel was able to segregate patients with MDD from those without MDD with a sensitivity and specificity of 64% and 67.9%, respectively.

CONCLUSION

Further research to identify MDD-specific markers is needed to improve the performance of this biological test.