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We studied influence of the anxiety-related trait Harm Avoidance and the COMT gene, which is an important modulator of prefrontal functioning, on event-related potentials in oddball paradigm and performance effectiveness of selective attention. For 50 individuals accuracy and time of searching words among letters at any desired rate and then under an instruction to perform the task as quickly and accurate as possible were measured. Scores on the Harm Avoidance scale from Cloninger's Temperament and Character Inventory, N100 and P300 parameters, and COMTVa1158Met genotypes were obtained for them as well. Searching accuracy and time were mainly related to N100 amplitude. The COMT genotype and Harm Avoidance did not affect N100 amplitude; however, the N100 amplitude modulated their effects on accuracy and time dynamics. Harm Avoidance was positively correlated with P300 latency. The results suggest that anxiety and the COMT gene effects on performance effectiveness of selective attention depend on cognitive processes reflected in N100 parameters.

The brain-derived neurotrophic factor (BDNF) gene is a prominent candidate gene for schizophrenia. The BDNFVal66Met polymorphism has been extensively studied for association to this disease. There is accumulating evidence that the polymorphism is associated with clinical presentations of schizophrenia and not with the disease itself. We compared the allele and genotype distribution in patients (n=1785) and healthy controls (n = 1092) and did not find association of the Va166Met polymorphism with schizophrenia. No association was found with affective syndromes. At the same time, the ValVal genotype was associated with the higher anxiety level assessed with the PANSS in male patients. We studied personality characteristics using personality questionnaires EPI, MMPI, STAI (n=363) and cognitive functions (attention (n=227) and verbal fluency (n=392). Patients with the ValVal genotype demonstrated higher levels of anxiety assessed by the MMPI and better performance on the neurocognitive tests. The interaction effect of genotype and trait anxiety, measured with the STAI, on cognitive functions was identified. In patients with higher anxiety, the performance on cognitive tests did not depend on the genotype, while in patients with lower levels of anxiety the ValVal gen- otype was associated with the better performance. This effect should be taken into account when studying the association of the Val66Met polymorphism with cognitive functions in patients with schizophrenia.

Authors investigated effects of the Val66Met polymorphism of the brain-derived neurotrophic factor (BDNF) gene and level of trait anxiety on attention in 90 patients with schizophrenia or schizoaffective psychosis. Attention was assessed using auditory event-related brain potentials (ERPs) and neuropsychological testing. There was a significant effect of the BDNF genotype, but not anxiety, on performance on the neuropsychological test and on the P300 amplitude in frontal and temporal leads. Carriers of a Met allele performed worse and showed lower P300 amplitude during the attention task than those with the ValVal genotype. The interaction effect of the genotype and anxiety was observed for non-target N100 amplitude in central and parietal leads. This effect depended on the level of anxiety: the interaction was significant only in the group with the lower level of anxiety. In this group, a Met allele was associated with the lower N100 amplitude. It was suggested that BDNF genotype does not contribute to brain electrical activity at the first stage of stimulus recognition (N100) because highly anxious people tend to be more attentive, regardless of genotype, due to the fear about their ability to cope with the task requirements.

To evaluate a role of dopamine transmission in the theory of mind (ToM) dysfunction in schizophrenia, authors studied the association of ToM with COMT and DRD2 gene polymorphisms in 209 patients with schizophrenia and 172 healthy people. All subjects performed second-order false belief (FB2) and faux pas stories. The association between the COMT Val158Met polymorphism and performance on FB2 was found. The association was sex-specific. The worse performance was associated with a Met allele in female patients and with the ValVal genotype in male ones. A correlation analysis of the COMT Val158Met polymorphism, performance on FB2 task, neurocognitive and clinical symptoms suggests that in female patients the association was modified, in part, by the higher stress sensitivity caused by the severity of clinical symptoms and its consequences for cognitive functioning.

Active search for candidate genes whose polymorphisms are associated with human cognitive functions has been in progress in the past years. The study focused on the role that the insulin-like growth factor II (IGF2) gene may play in the variation of cognitive processes related to executive functions. The ApaI polymorphism of the IGF2 gene was tested for association with selective attention during visual search, working memory/mental control, and semantic verbal fluency in a group of 182 healthy individuals. The ApaI polymorphism was associated with the general cognitive index and selective attention measure. Carriers of genotype AA displayed higher values of the two parameters than carriers of genotype GG. It was assumed that the ApaI polymorphism of the IGF2 gene influences the human cognitive functions, acting possibly via modulation of the IGF-II level in the central nervous system.

Growing evidence suggest that interleukin-1beta (IL-1B) and interleukin-1 receptor antagonist (IL-1RN) are involved in the pathogenesis of schizophrenia. The objective of this study was to test the association of the functional promoter polymorphism 511T>C of the IL-1B gene and the VNTR polymorphism of the IL-1RN gene with clinical symptoms of schizophrenia. We studied 758 patients, 415 men and 343 women, with the ICD-10 diagnosis of schizophrenia. Symptoms of schizophrenia were measured using the Positive and Negative Symptome Scale (PANSS). The sample was stratified by gender and type of schizophrenia (chronic or episodic). We found the association between the VNTR IL-1RN polymorphism and PANSS negative symptoms (p = 0.02) in men. Male patients with the genotype 2*2 had lower scores than those with 1*2 and 1*1 genotypes. The genotype 2*2 was associated with a more severe illness course (shorter illness duration and smaller number of hospitalizations) as well. The results suggest that the VNTR polymorphism in the IL-1RN gene may be a predictor of outcome of schizophrenia in men.

Platelet serotonin content in patients in the acute period of stroke is an important index of clinical changes during the post stroke period as well as a predictor of development of mental disorders. We studied the association between two polymorphisms (5-HTTLPR and Val66Met BDNF) and the platelet serotonin content in 47 patients with stroke. We also investigated the moderating effect of genetic variants on the association between platelet serotonin content and development of affective and anxiety disorders in stroke patients in the acute period of stroke. The interaction effect of two polymorphisms on levels of platelet serotonin was found. The lowest level was observed in patients with the diplotype LL*ValVal, the highest level--in the group of patients with the LL genotype and genotypes containing at least one copy of a Met allele. No moderating effect of genetic variants on the relationship between serotonin content and affective or anxiety disorder was found.

The elevated level of homocysteine has been repeatedly observed in patients with schizophrenia. Molecular-genetic studies revealed the association between schizophrenia and polymorphisms of two genes - methylenetetrahydrofolate reductase (MTHFR) and cystathionine-beta-synthase (CBS) involved in the conversion of homocysteine to methionine and cysteine, respectively. Authors have studied the association of C677T MTHFR and 844ins68 CBS polymorphisms with attention in 105 schizophrenic patients (56 women and 49 men) by measuring auditory evoked potentials and concentration of attention. Women with a genotype containing an insertion (Ins+) had the shorter latency of N100 in the frontal leads compared to those with the Ins- genotype. The results of the neuropsychological study revealed that women with Ins+ genotypes performed better on the test as well. In conclusion, the 844ins68 CBS polymorphism is associated with attention in patients with schizophrenia.

Genetic factors are thought to contribute to schizotypal dimensions. Recently, a number of genetic variants associated with schizotypal traits in psychiatrically healthy people have been found. Authors reported earlier the association between the SERT 5-HTTLPR polymorphism and schizotypal traits measured with MMPI. The present study aimed at the replication of association on a larger sample using other questionnaires and methods of data analysis. The sample comprised 657 people from the Russian population. MMPI, SPQ-74 and TCI-125 were used to measure personality traits. Based on the results of psychological testing, the sample was divided into high risk and control groups. For MMPI, the high risk group included people with the elevation on scale Schizophrenia, for SPQ-74 - people with a total score more than 25 and for TCI-125 - people with lower scores on scale Cooperation and higher scores on Self-Transcendence. In all high-risk groups assessed by different psychological instruments, the frequency of the SS 5-HTTLPR genotype was significantly lower as compared to the corresponding control groups. MANCOVA also showed that individuals with the SS genotype had lower scores on scales related to schizotypal traits. Thus, we have confirmed our previous results on the association between the 5-HTTLPR polymorphism and schizotypal traits in psychiatrically healthy subjects.

The DRD2 Ser311Cys polymorphism was studied in a sample which included 366 patients with schizophrenia and 387 healthy controls. The frequency of the Cys allele was significantly higher (p<0,009) in the group of patients compared to the controls (8,5% and 3,9%, respectively). Sustained attention assessed by P300 parameters was studied in 66 patients with the SerSer and SerCys genotypes (the CysCys genotype was not observed in the sample studied). A significant effect (p=0,01) of the SerCys genotype on P300 latency in frontal, central and temporal regions was found. Patients with the at-risk allele presented delayed latencies that reflected the lower speed of mental processes related to activation of attention resources. In conclusion, our data support the evidence of association between the Cys allele and schizophrenia obtained earlier for other populations and revealed that carriers of the genotype containing the at-risk allele had delayed P300 latencies.

The synaptosomal-associated protein (SNAP-25) plays an integral role in synaptic transmission and in memory consolidation in the hippocampus. Recently an association between SNAP-25 gene polymorphism and cognitive ability has been reported in two independent studies of healthy people and patients with schizophrenia. Authors carried out an association study of MnlI SNAP-25 polymorphism and performance on neurocognitive tests measuring verbal memory, attention/executive functions in 66 patients with major psychosis, 75 their relatives and 136 controls. MANCOVA revealed a significant effect of group (small er, Cyrillic=0,00001) and genotype (small er, Cyrillic=0,012) as well as an interaction effect between group and genotype (small er, Cyrillic=0,02) on the performance on neurocognitive tests. Carriers of the TT genotype performed worse on the most tasks compared to other genotypes. The similar character of the MnlI SNAP-25 polymorphism effect on the variability of neurocognitive traits in all groups suggests the relationship between this gene and general cognitive ability.

To investigate the effect of Val66Met BDNF and 5-HTR2A T102C polymorphisms on the characteristics of voluntary and involuntary visual attention, 89 patients with schizophrenia, 91 their well relatives and 163 controls have been studied. Attention was assessed using a modified version of the Munsterberg test. The significant interaction effect of the BDNF, 5-HTR2A and diagnosis on attention characteristics was found (p=0,04). Carriers of the Val/Val genotype demonstrated higher scores of both voluntary and involuntary attention and those with the A1 (T) allele needed more time for the performance of the test. The combination of the A1 allele with a Met BDNF allele was associated with lower scores of voluntary attention and higher scores of involuntary attention. The study confirmed the impairment of selective attention in patients with schizophrenia and their relatives while any pathological changes in involuntary attention were not observed. The effect of genotypes was presented irrespective of diagnostic group studied. The data obtained suggest that carriers of the Val/Val genotype are able to allocate more attentional resources to process external stimuli. At the same time, the possibility that this polymorphism is likely associated with specific visual-spatial abilities than with attention as such or general cognitive resources can not be excluded.

An association between serotonin transporter gene 5-HTTLPR polymorphism and development of depressive states in response to different distant and proximal stressors has been reported previously. We studied 5-HTTLPR polymorphism effect on probability of development of mental maladaptation and its peculiarities in 224 relatives of patients with severe chronic mental disorders: schizophrenia, schizoaffective and affective disorders. The SS genotype was associated with elevation on the scale Hypochondriasis of the MMPI that indicated intensity of the autonomic component of anxiety and more concern about health as well as increased sensitivity. At the same time, its relation to depression and anxiety measured by the scale Depression was tentative. The association was stronger in men than in women. Moreover, men with the SS genotype were more tense, suspicious, detached and experienced difficulties in concentration (scales Paranoia and Schizophrenia) as compared to those with other genotypes. The results imply a role of the short allele in augmenting and modulation of psychopathological reaction in response to chronic stressful situation in relatives of psychotic patients.

To elucidate main effects of dopamine receptor D4 (DRD4) and cathecol-O-methyltransferase (COMT) genes as well as their interaction effect on neurocognitive traits, DRD4 gene polymorphisms (-809G/A, -521C/T) and the COMT gene Val158Met polymorphism, along with characteristics of verbal memory, executive functions and peculiarities of associative processes, have been studied in 150 patients with schizophrenia, 83 their relatives and 118 mentally healthy subjects without positive family history of psychosis. A main effect of -521C/T polymorphism and DRD4 (-521C/T).Vall58Met polymorphisms interaction were found for verbal fluency, carriers of the Val/Val+CC and the Met/Met+TT genotypes performing better on this task as compared to other genotypes. An interaction DRD4 (-521C/T).Val158Met effect on originality of speech associations was observed in the combined group of unaffected individuals (relatives and controls), with lower scores of the trait in those with the Met/Met+CC genotype. The COMT-DRD4 (-809G/A) interaction effect on working memory was demonstrated for patients and unaffected individuals, homozygotes for the Val and the G alleles having the best results and homozygotes for the Met and the A alleles--the worst ones. The data obtained suggest the relationship of DRD4 and COMT genes with different characteristics of executive functions but not with verbal memory.

Serotonin transporter gene is known to be implicated with various psychological and psychiatric phenotypes. The present study aimed at searching for relationship of the gene polymorphism 5-HTTLPR to personality traits and P300 wave in patients with schizophrenia (n = 71) and their non-psychotic relatives (n = 74). To reduce an influence of the P300 amplitude range, which may vary widely in population, subjects have been divided into 2 groups: with amplitude higher (group m+) and lower (group m-) than a mean sample value. Between-amplitude differences were highly significant (p < 0.0001) for all the leads. The groups were similar by age, sex ratio and emotional level measured with personality inventories. When compared by 5-HTTLPR genotype, mean P300 amplitude values were similar in the group m-. In the group m+, significant differences for this component were found between the II genotype and the ss genotype at frontal (p = 0.02) and central (p = 0.005) leads, with the ss genotype subjects having the lowest amplitude. Subjects with the ss genotype in this group as compared to those with the II genotype were also featured by higher anxiety- and depression-related personality traits in relatives and marked clinical symptoms related to anxiety and depression in patients. The fact that association between 5-HTTLPR polymorphism and with P300 amplitude as well as personality traits was found only in the group with higher amplitudes, but not in the group with lower amplitudes, may be partly explained by the assumption that these groups represent different phenotypes. Subjects with inherent lower amplitude are thought to have reduced ability of behavior self-regulation. In conclusion, 5-HTTLPR polymorphism seems to contribute to information processing related to P300 generation and to anxiety and depression traits in patients with schizophrenia and their relatives.

The changes of P300 parameters (lower amplitude and increased latency) are thought to be the most prominent phenomena of schizophrenia. A role of gene polymorphism in P300 generation was supported by several associative studies in psychiatrically well subjects and patients with mental disorders. We studied P300 parameters and the following polymorphisms: T102C for the serotonin receptor type 2A (5-HTR2A) gene, the 5-HTTLPR for the serotonin transporter gene, -809G/A, -616G/C N -52C/T SNPs in the promoter region of the dopamine D4 receptor (DRD4) gene and the Val158Met polymorphism of the catechol-O-methyltransferase (COMT) in 74 patients with schizophrenia and spectrum disorders and 71 their first-degree relatives. No association was found between serotonergic system genes and P300. The -809G/A DRD4 gene polymorphism was related to amplitude in all frontal leads (p=0,01) in patients. In relatives, an association was observed between -521C/T DRD4 variants and latency (p=0,005) as well as between the COMT gene polymorphism and P300 amplitude (p=0,004) at the central lead. Thus, the genes involved in dopaminergic system play a role in P300 generation both in patients with schizophrenia and spectrum disorders and their relatives.

A vast body of associative studies reported a role of highly polymorphic dopamine receptor DRD4 gene in regulation of emotional processes and development of mental disorders. The present study addresses allele, genotype and haplotype distribution of 3 polymorphic DRD4 markers (-809G/A, -616G/C N -521C/T) in Russian patients with schizophrenia spectrum disorders and their relation to the disease and personality traits. A sample included 151 patients with iCD-10 diagnosis of schizophrenia, schizoaffective psychosis and schizotypal personality disorders, 89 their first-degree non-psychotic relatives and 131 mentally healthy individuals. No differences in allele and genotype frequency was found between the patients and the controls. Transmission disiquilibrium test (TDT) did not reveal a preferential transmission of either allele from parents to proband. The 521C/T N -616G/C markers were linked to the disease when the EH program has been used in the analysis. Patients with the GG (-809G/A) and GG (-616G/C) genotypes had higher scores on the Hypomania scale (MMPI) comparing to the GA(-809G/A)+AA(-809G/A) and GC(-616G/C)+CC(-616G/C) genotypes but the association did not reach a level of significance (p = 0.06). The results confirmed the literature reports on the relation of the DRD4 gene to schizophrenia and personality traits related to social activity.

Polymorphic marker Ser9Gly of dopamine receptor D3 gene is considered perspective for associative studies of schizophrenia. Allele and genotype frequency of this polymorphism were studied in different ethnic groups of schizophrenic patients as well as the attempts have been made to reveal an association with clinical presentations of the disease. However, the results are inconsistent. The present study aimed at investigating Ser9Gly DRD3 gene polymorphism in Russian sample of schizophrenic patients. One hundred and fifty patients with ICD-10 diagnosis of schizophrenia (broad definition), 69 male and 81 female, aged 34.8+/-13.87 years, age at disease onset 24.3+/-9 years, have been examined. Control group consisted of 150 healthy subjects without family history of schizophrenia, 60 male and 90 female, aged 32.7+/-13.5 years. No between-group differences have been found for Ser9Gly DRD3 allele and genotype frequencies. However, a frequency of homozygous genotype Gly/Gly was significantly higher in female patients, comparing to female controls (p=0.038 Yate's corrected, OR 9. CI 0.95% 1.0-79.5). A role of sex-dependent association between Ser9Gly DRD3 polymorphism and schizophrenia is discussed.

Current concepts on the role of genetic factors in the development of schizophrenia and on the relative risk for this disease and spectrum disorders are reviewed. An analysis of the results of genetic counseling of 120 subjects revealed that, comparing to other mental disorders, patients with schizophrenia or relatives, mostly those having a schizophrenic parent (40%) or spouse (25%), referred more frequently for a consultation. Most of the referrals (70%) had a high educational level. As it was found out during the counseling, up to 20% of the relatives met a diagnosis of psychiatric disorders, mostly personality disorder (9%) and depressive state (7%). Psychological testing with personality inventories revealed a high level of personality abnormalities (schizoid--22%, hyperthymic--16% and obsessive-anxiety--4%) in 43% close relatives of patients seeking medicogenetic advice. The genetic counseling featured by the use of the comprehensive approach, basing on all obtained data (psychiatric, psychological, neurophysiologic etc.), that increases its accuracy and may assist families in taking a reasonable decision in birth planning.