Pterin metabolism, inflammation and oxidative stress biochemical markers in schizophrenia: Factor analysis and assessment of clinical symptoms associations

Various aspects of folate and tetrahydrobiopterin (BH4) metabolism disturbances have been detected in patients with schizophrenia.Data were obtained that disturbances in the pterins (folates and BH4) metabolism can be associated with oxidative stress and inflammation, but has not yet been confirmed in clinical studies in schizophrenia. Within the framework of this study, a correlation and factor analysis of biochemical markersof pterin metabolism, inflammation and redox imbalance in patients with schizophrenia was performed in order to test the hypothesis of the single etiopathogenetic node, including the studied biochemical processes. Methods: 125 patients with schizophrenia and 95 healthy volunteers were randomly selected and evaluated with a biochemical examination of BH4, folate, B12, homocysteine, C-reactive protein, interleukin-6, reduced glutathione levels in the blood serum; activity of superoxide dismutase and catalase - in erythrocytes; malondialdehyde - in blood plasma. All patients underwent an examination using standardized psychopathology rating scales. Spearman rank coefficient (ρ) with Benjamini-Hochberg correction was used for the correlation analysis. The principal components analysis (PCA) was used as a factor analysis. Results: Significant correlations were found within groups of pterin metabolism, inflammatory markers and redox-imbalance, and also between separate inflammation, oxidative stress and markers of pterin metabolism. The performed factor analysis made it possible to distinguish two components: 1 - pterin metabolism, 2 - oxidativeinflammatory markers. Despite the weak statistical associations and, possibly, functional relationships between pterin metabolism and oxidative/inflammation markers, each of the components has its own clinical correlates and, probably, a separate contribution to the pathology of schizophrenia.

[Comorbidity patterns and structure of depressive episodes in patients with bipolar disorder and major depressive disorder]

OBJECTIVE

To conduct an exploratory analysis of comorbidity patterns and the structure of depressive episodes among Russian patients with bipolar disorder (BD) and major depressive disorder (MDD).

MATERIAL AND METHODS

This multicenter cross-sectional study included 178 patients with mood disorders, of which 78.1% (n=139) were women. The diagnosis of BD was made in 68.0% (n=121) patients, of them 37.1% (n=66) were diagnosed with BD type I. All study participants underwent a structured Mini International Neuropsychiatric Interview to verify the clinical diagnosis and identify concomitant mental disorders, and also filled out an electronic case report form. Statistical analysis was performed in RStudio v. 1.4.1717 using the standard R package and the «psych» package.

RESULTS

According to the results of stepwise regression, comorbid diagnoses of panic disorder (OR=5.3; 95% CI 1.9-19.1) and eating disorders (OR=7.7; 95% CI 2.8-27.4) were more associated with BD. In addition, depressive episodes in BD were more associated with symptoms of hypersomnia (OR=2.5; 95% CI 1.2-5.3) and psychomotor retardation (OR=3.2; 95% CI 1.5-7.6). Symptoms such as increased appetite (47.1% (n=57) vs 26.3% (n=15); p=0.009), ideas of guilt (92.6% (n=112) vs 7.2% (n=44); p=0.006) and thoughts of self-harm or death (70.2% (n=85) vs 45.6% (n=25); p=0.003) were also nominally more common in depressive episodes within the BD compared to MDD.

CONCLUSIONS

Mood disorders such as BD and MDD have significant differences in the patterns of comorbidity and the structure of depressive episodes, which is important to consider when conducting differential diagnosis of these disorders. The results also indicate the need for a comprehensive diagnostic interview with patients with mood disorders to assess the presence of comorbid mental disorders during life and the structure of depressive episodes throughout the clinical course from the moment of onset.

[Anhedonia in mood disorders and somatic diseases: results of exploratory Mendelian randomization analysis]

OBJECTIVE

To conduct an exploratory Mendelian randomization analysis of the causal relationships of anhedonia with a wide range of psychiatric and somatic phenotypes based on the genetic data of participants in a population study.

MATERIAL AND METHODS

This cross-sectional study included 4520 participants, of which 50.4% (n=2280) were female. The mean age was 36.8 (S.D.=9.8) years. Participants were pheno-nailed based on the DSM-5 criteria for anhedonia in the framework of depression. An episode of anhedonia exceeding 2 weeks during life was reported by 57.6% (n=2604) of participants. A genome-wide association study (GWAS) of the anhedonia phenotype was performed, as well as a Mendelian randomization analysis using summary statistics of large-scale GWASs on psychiatric and somatic phenotypes.

RESULTS

The GWAS on anhedonia did not reveal the variants with genome-wide significant association (p<10^-8). The most significant (p=9.71×10^-7) was the variant rs296009 (chr5:168513184) in an intron of the slit guidance ligand 3 (SLIT3) gene. Using Mendelian randomization, nominally significant (p<0.05) causal associations of anhedonia with 24 phenotypes were identified, which can be divided into 5 main groups: psychiatric/neurological diseases, inflammatory diseases of the digestive system, respiratory diseases, oncological diseases and metabolic disorders. The most significant causal effects of anhedonia were found for breast cancer (p=0.0004, OR=0.9986, 95% confidence interval (CI) (0.9978-0.999)), minimal depression phenotype (p=0.009, OR=1.004, 95% CI (1.001-1.007)), as well as for apolipoprotein A (p=0.01, OR=0.973, 95% CI (0.952-0.993)) and respiratory diseases (p=0.01, OR=0.9988, 95% CI (0.9980-0.9997)).

CONCLUSION

The polygenic nature of anhedonia may cause the risks of comorbidity of this phenotype with a wide range of somatic diseases, as well as may be associated with mood disorders.

[Association of depression and anxiety with somatic diseases: negative lifestyle factors impact]

OBJECTIVE

To assess the associations of various depression and anxiety phenotypes with manifestations of different somatic disorders and negative lifestyle factors.

MATERIAL AND METHODS

The study involved 5116 people. In the online questionnaire, participants provided information about age, sex, height and weight, as well as a history of smoking, alcohol use, physical activity and diagnoses/symptoms of various physical diseases. Self-questions based on the DSM-5 criteria and the online version of the HADS were used to screen for phenotypes of affective and anxiety disorders in a population sample.

RESULTS

An association of both subclinical and clinical depressive symptoms on HADS-D was noted for respondents with weight gain (OR 1.43; CI: 1.29-1.58, p<0.05 and OR 1,CI: 1.05-1.52, p<0.05, respectively), increased BMI (OR 1.36; CI: 1.24-1.48, p<0.05 OR 1.27; CI: 1.09-1.47, p<0.05 respectively), and decreased physical activity (OR 1.67; CI: 1.35-2.07, p<0.05 and OR 2.35; CI: 1.59-3.57, p<0.05, respectively) at the time of testing. The phenotypes of depression, anxiety disorders, and bipolar disorder by DSM criteria were associated with a history of smoking. (OR 1.37; CI: 1.18-1.62, p<0.001; OR 1.36; CI: 1.24-1.48, p<0.05 and OR 1.59; CI: 1.26-2.01, p<0.001, respectively). For higher BMI the association was reported only for the bipolar depression phenotype (OR 1.16; CI: 1.04-1.29, p<0.05), and with a decrease in physical activity - for the phenotypes of major depression and anxiety disorders (OR 1.27; CI: 1.07-1.52, p<0.05 and OR 1.61; CI: 1.31-1.99, p<0.001, respectively). A significant association with various somatic disorders was noted for all phenotype variants, but to the greatest extent for those based on DSM criteria.

CONCLUSIONS

The study confirmed the association of negative external factors and various somatic disorders with depression. These associations were noted for various phenotypes of anxiety and depression, both in severity and structure, and may be due to complex mechanisms that have shared biological and environmental mechanisms.

Features of Temperament and Character in Families with Recurrent Depressive and Bipolar Affective Disorders

The research is devoted to the study of temperament and character characteristics in families with mood disorders (recurrent depressive disorder (RВВ) and bipolar affective disorder (BD)). Many temperament and character traits tend to aggregate in families and influence the risk of RDD and BD. At the same time, no studies have been conducted in the Russian population with an assessment of temperament and character traits depending on the presence of mood disorders in families. The hypothesis of the study: patients with mood disorders and their relatives have specific features of temperament and character. 36 probands with RDD and BD and 68 of their relatives were examined, as well as 23 probands without mood disorders and 53 of their relatives. A Cloninger&apos;s Temperament and Character Inventory (TCI-125) was used to assess personality traits. The results of the study showed that probands with mood disorders, in comparison with their relatives, had significantly higher scores on such TCI-125 dimensions as novelty seeking, harm avoidance, and reward dependence. However, the main contribution to the identified differences was made by relatives without mood disorders. Probands with mood disorders had a higher score on the dimension of harm avoidance compared to healthy probands. In addition, a higher score on the novelty seeking dimension was associated with the absence of relatives with mood disorders when comparing healthy relatives of probands with mood disorders and healthy relatives of probands without mood disorders. It is concluded that there are specific temperament traits in families with mood disorders that can be considered as candidates for the endophenotypes of RDD and BD.

[Association of anhedonia with comorbid mental disorders, suicidality and personality traits in patients with depression]

OBJECTIVE

A comprehensive assessment of anhedonia in patients with depression, considering their demographic, clinical and personality characteristics.

MATERIAL AND METHODS

This cross-sectional, multicenter study included 190 patients with depression (63.7% women, mean age (Me) 31 (24-46.5) years) diagnosed with a depressive episode (F32) and recurrent depressive disorder (F33) according to the ICD criteria regardless of the disease stage (exacerbation or remission). Comorbid mental disorders of the anxiety spectrum, eating behavior, substance abuse, and psychotic symptoms were assessed and recorded. The Snaith-Hamilton Pleasure Scale (SHAPS) was used to assess the severity of anhedonia.

RESULTS

Patients with an earlier onset of depression (p=0.037) and a history of suicide attempts (p=0.001) showed higher scores for anhedonia. The generalized anxiety disorder, panic disorder, bulimia nervosa, and alcohol dependence in patients with current depression were associated with higher anhedonia. The anhedonia scores had moderate positive correlations with a number of personality traits on TCI-125: Harm Avoidance (r=0.30; p<0.01), as well as weak negative correlations with Reward dependence (r= -0.20; p<0.05) and Cooperativeness (r= -0.26; p<0.05). There were also weak positive correlations of anhedonia scores with the severity of suicidal ideation and suicidal risk (for the last month and throughout life) and moderate positive correlations with the severity of suicidal behavior throughout life.

CONCLUSIONS

The study confirms and expands the information about the complex nature of the anhedonia phenomenon in patients with depression. Further research on anhedonia may help in clinical practice and become the basis for the search for new biomarkers of depression.

Tetrahydrobiopterin deficiency in schizophrenia: Biochemical and clinical aspects

It was reported that the levels of tetrahydrobiopterin (BH4) are reduced in schizophrenia. However, mechanisms of BH4 deficiency in schizophrenia had not been studied precisely.

OBJECTIVE

the search of the association between BH4 deficiency in schizophrenia and a range of biochemical and clinical parameters for the evaluation of the possible mechanisms of BH4 loss and its role in the development of the symptoms.

METHODS

93 patients with schizophrenia and 60 healthy volunteers were randomly selected and evaluated with a biochemical examination of BH4, folate, cobalamin (B12), homocysteine, C-reactive protein (CRP), reduced glutathione (GSH) levels in the blood serum.Patients underwent standardized psychopathological examination.

RESULTS

In patients, the levels of BH4 and folate were lower (p = 0.001 and p = 0.054, respectively), and the levels of homocysteine were higher (p = 0.012) compared to the control group. BH4 levels directly moderately correlated with folate (ρ = 0.43; p = 0.0029) and B12 levels (ρ = 0.43; p = 0.0020) and inversely moderately correlated with homocysteine levels (ρ = -0.54; p = 0.00015) in patients. Cluster analysis identified schizophrenia biotype characterized by a deficiency of BH4, folate, B12, and hyperhomocysteinemia. The clinical characteristics of this biotype were not specific. CRP and GSH were higher in patients compared to controls, but their association with serum BH4 was not confirmed.

[Modern approaches to the genetics of depression: scopes and limitations]

SUMMARY

Recent findings in candidate genes for depression showed significant replication failures and thus appeared irrelevant. Much of the earlier studies' limitations can be overcome by the strategy of genome-wide association studies (GWAS), which aims to identify associations between different genomic variants and phenotypic traits without pathophysiological hypotheses application. With the use of such studies, it seems possible to calculate polygenic risk scores (PRS) as a promising approach for predicting depression risk. The aim of this review is to analyze modern approaches of genetic research used to assess the risk of depression in a population.

[Family history of affective disorders, the gender factor and clinical characteristics of depression]

OBJECTIVE

Analysis of clinical features of development and course of depression in patients with FH of mood disorders taking into account sex differences.

MATERIAL AND METHODS

This multicenter cross-sectional study included patients over 18 years of age with depressive episode/recurrent depressive disorder. Clinical characteristics of depression, presence of comorbid mental illness and family history (FH) information were obtained in a structured clinical interview.

RESULTS

One hundred and seventy-one patients (mean age (M (SD)) 40.87 (15.86) y.o.), including 64.5% of women, were enrolled in the study. FH was revealed in 30.2% of patients. The proportion of FH did not differ in men and women (p=0.375). Generalized anxiety disorder (GAD) was more frequent in FH positive patients (p=0.016). Logistic regression also revealed that FH is a risk factor for concomitant GAD (p=0.019, OR=2.4). The GLM demonstrated a significant joint effect of FH and sex on the maximum duration of a depressive episode (p=0.044), as well on the number of suicide attempts (p=0.055) and the number of depressive episodes as a trend (p=0.072).

CONCLUSION

We have demonstrated the specific interaction of FH of mood disorders with sex on clinical course of depression. Thus, the manifestation of a genetic influence on the clinical phenotype of depression can be significantly moderated by sex.

[Schizophrenia and cardiometabolic disorders]

The aim of this review is to analyze the basic biological mechanisms of comorbidity of schizophrenia and metabolic, cardiovascular diseases, which are not directly associated with external risk factors. The study of the general pathophysiological mechanisms of schizophrenia and metabolic disorders can provide a significant basis not only for the fundamentally novel therapeutic, preventive and diagnostic measures, but also for a better understanding of the etiopathogenesis of these diseases. It seems likely that schizophrenia represents a heterogeneous group with a varying genetic basis for both mental symptoms and neuroendocrine, inflammatory processes that form concomitant somatic disorders. Thus, the new integrated approaches to the study of this problem with the latest methods of genetic and molecular research are relevant.

[GWAS-based polygenic risk scores for depression with clinical validation: methods and study design in the Russian population]

Depression is one of the leading causes of decreased quality of life and social functioning of patients. In the context of preventive medicine, the prevention of depression becomes a priority. To achieve the goals of prevention, it is necessary to identify specific population risk groups - individuals with a high genetic risk of depression. The paper describes the project aimed at developing a genetic test system based on polygenic risk scores (PRS) for depression, considering the multi-ethnicity and multicultural diversity of the Russian population. As a result of the study, data on the genetic architecture of depression (GWAS) and PRS for depression will be obtained for the first time. The emergence of a genetic test system developed in the study of the Russian population and in the conditions of a constant decrease in the cost of genetic research will allow an effective transition to preventive medicine in the area of mental health.

Structure of anxiety associated with СOVID-19 pandemic: the online survey results

The COVID-19 pandemic imposed not only serious threats to the physical health of the population, but also provoked a wide range of psychological problems. The study was aimed to define the structure of anxiety in the population during the epidemic period, as well as to identify the most vulnerable social groups (including individuals with affective disorders) which were most in need of psychological and/or psychiatric help. The online survey of 1957 Russian-speaking respondents aged over 18 was carried out from March 30 to April 5, 2020. The anxiety distress level was verified using the Psychological Stress Measure (PSM-25), the stigmatization of individuals experiencing respiratory symptoms was assessed using the modified Perceived Devaluation-Discrimination Questionnaire (PDD; Cronbach's α = 0.707). In 99.8% of respondents, the combination of various concerns associated with COVID-19 was observed, the mean psychological stress score was increased to moderate level (score 104.9 ± 34.4), and the stigmatization score exceeded the whole sample median value (19.5±3.4; Me = 17). About 35% of respondents had concerns associated with anxiety distress (Cohen’s d = 0.16–0.39): these were the "risk of social isolation" and the "possible lack of medication for daily use". The following groups of respondents were the most susceptible to the stress: people with affective disorders, young people (aged ≤20), unemployed persons, single persons, people with no formal education, and women. Thus, the broad sectors of the population need correction of anxiety distress associated with the COVID-19 pandemic. Therefore, the measures’ implementation should be targeted, and in terms of coverage and content oriented to the identified vulnerable social groups.