Classical Risk Factors and Inflammatory Biomarkers: One of the Missing Biological Links between Cardiovascular Disease and Major Depressive Disorder.

BACKGROUND: Cardiovascular disorders (CVD) and major depressive disorder (MDD) are the most frequent diseases worldwide responsible for premature death and disability. Behavioral and immunological variables influence the pathophysiology of both disorders. We therefore determined frequency and severity of MDD in CVD and studied whether MDD without CVD or other somatic diseases influences classical and inflammatory biomarkers of cardiovascular risk. In addition, we investigated the influence of proinflammatory cytokines on antidepressant treatment outcome. METHODS: In a case-control design, 310 adults (MDD patients without CVD, CVD patients, and cardiologically and psychiatrically healthy matched controls) were investigated. MDD patients were recruited after admission in a psychiatric university hospital. Primary outcome criteria were clinical depression ratings (HAM-D scale), vital signs, classical cardiovascular risk factors and inflammatory biomarkers which were compared between MDD patients and healthy controls. RESULTS: We detected an enhanced cardiovascular risk in MDD. Untreated prehypertension and signs directing to a metabolic syndrome were detected in MDD. Significantly higher inflammatory biomarkers such as the high sensitivity C-reaktive protein (hsCRP) and proinflammatory acute phase cytokines interleukine-1ß (IL-1ß) and interleukine-6 (IL-6) underlined the higher cardiovascular risk in physically healthy MDD patients. Surprisingly, high inflammation markers before treatment were associated with better clinical outcome and faster remission. The rate of MDD in CVD patients was high. CONCLUSIONS: Patients suffering from MDD are at specific risk for CVD. Precise detection of cardiovascular risks in MDD beyond classical risk factors is warranted to allow effective prophylaxis and treatment of both conditions. Future studies of prophylactic interventions may help to provide a basis for prophylactic treatment of both MDD and CVD. In addition, the high risk for MDD in CVD patients was confirmed and underlines the requirement for clinical attention.

Associations of NEUROD2 polymorphisms and change of cognitive dysfunctions in schizophrenia and schizoaffective disorder after eight weeks of antipsychotic treatment.

INTRODUCTION: NEUROD2 is a neurospecific helix-loop-helix transcription factor which has an impact on the regulation of glutamatergic and GABAergic genes. We investigated an association of NEUROD2 with neurocognitive dysfunctions in schizophrenia and schizoaffective disorder patients before and during treatment with different second-generation antipsychotics. METHODS: Patients were genotyped for four different polymorphisms of the NEUROD2 gene ((rs9889354(A/G), rs1877032(C/T), rs12453682(C/T) and rs11078918(C/G)). Cognitive function was assessed at baseline and week 8. Results of individual neuropsychological tests were assigned to six cognitive domains (reaction time and quality; executive function; working, verbal and visual memory) and a general cognitive index. RESULTS: 167 patients were included in the study. The NEUROD2 exonic polymorphism rs11078918 showed significant associations with verbal memory and executive functions, whereas the NEUROD2 polymorphism rs12453682 was significantly associated with working and verbal memory, executive functions and with a cognitive index. Significant associations were found at baseline and after eight weeks. Moreover, significant associations between the change in neuropsychological test results during antipsychotic treatment and the NEUROD2 polymorphisms rs11078918 and rs12453682 were observed. CONCLUSIONS: Our findings suggest that the NEUROD2 gene could play a role in the pathophysiology of neurocognitive dysfunctions as well as in the change of cognitive symptoms under antipsychotic treatment in schizophrenia and schizoaffective disorder.

Oxytocin and vasopressin levels are decreased in the plasma of male schizophrenia patients.

OBJECTIVE: Impaired social functioning and autistic symptoms are characteristics of schizophrenia. The social hormones oxytocin (OT) and arginine-vasopressin (AVP) both modulate social interaction and therefore may be involved in the pathogenesis of schizophrenia. We investigated whether men with schizophrenia show altered OT and AVP levels compared with healthy controls (HC) and whether autism symptoms are associated with OT levels. METHODS: Forty-one men with non-acute schizophrenia and 45 matched HC were enrolled. Schizophrenia was assessed with the Positive and Negative Syndrome Scale (PANSS). Blood samples were collected on 2 days, and plasma OT and AVP levels were measured by ELISA immunoassay. RESULTS: The schizophrenia patients had significantly lower plasma OT levels than the HC; a similar trend was found for AVP. Plasma OT levels were associated with severe life events, fewer important attached persons, and a higher score on the PANSS negative scale; the most dominant PANSS items were 'preoccupation', 'emotional withdrawal', and 'passive/apathetic social withdrawal'. CONCLUSION: These findings support an association between the social hormones OT and AVP and schizophrenia. We suggest that OT metabolism may be altered in schizophrenia, but other possible causes for decreased plasma OT levels in schizophrenia patients include decreased OT synthesis, mRNA expression, and translation. Especially the 'autistic' symptoms of schizophrenia seem to be closely linked to an altered metabolism of OT, the 'attachment' hormone.

Tryptophan metabolism and immunogenetics in major depression: a role for interferon-γ gene.

The tryptophan metabolism and immune activation play a role in pathophysiology of major depressive disorders. The pro-inflammatory cytokine interferon-γ transcriptionally induces the indoleamine 2,3-dioxygenase enzyme that degrades the tryptophan and thus induces serotonin depletion. The polymorphism of certain cytokine genes was reported to be associated with major depression. We investigated the association between interferon-γ (IFNγ) gene CA repeat polymorphism, the profile of serotonin and tryptophan pathway metabolites and clinical parameters in 125 depressed patients and 93 healthy controls. Compared to controls, serum tryptophan and 5-hydroxyindoleacetic acid (5HIAA) concentrations in the patients were significantly lower and serum kynurenine concentrations were significantly higher at baseline (p<0.0001). The presence of IFNγ CA repeat allele 2 homozygous has significant association with higher kynurenine concentrations in controls (F=4.47, p=0.038) as well as in patients (F=3.79, p=0.045). The existence of interferon-γ CA repeat allele 2 (homo- or heterozygous) showed significant association with increase of tryptophan breakdown over time during the study period (F=6.0, p=0.019). The results indicated the association between IFNγ CA repeat allele 2, tryptophan metabolism and the effect of medication.

No influence of brain-derived neurotrophic factor (BDNF) polymorphisms on treatment response in a naturalistic sample of patients with major depression.

The role of the brain-derived neurotrophic factor (BDNF) in the pathophysiology of major depressive disorder (MDD) remains to be elucidated. Recent post hoc analyses indicated a potential association of three polymorphisms in the BDNF gene with worse treatment outcome in patients with the subtype of melancholic depression. We aimed at replicating these findings in a German naturalistic multicenter follow-up. Three polymorphisms in the BDNF gene (rs7103411, rs6265 (Val66Met) and rs7124442) were genotyped in 324 patients with MDD and 470 healthy controls. We applied univariate tests and logistic regression models stratifying for depression subtype and gender. The three polymorphisms were not associated with MDD as diagnosis. Further, no associations were found in univariate tests. With logistic regression, we only found a tendency towards an association of the rs6265 (Val66Met) polymorphism with overall response to treatment (response rates: GG (val/val) < GA (val/met) < AA (met/met); p = 0.0129) and some gender differences for the rs6265 (Val66Met) and rs7103411 polymorphisms. Treatment outcome stratified for subtypes of depression did not differ significantly between the investigated polymorphisms or using haplotype analyses. However, results showed a tendency towards significance. At this stage, we cannot support an influence of these three polymorphisms. Further studies in larger patient samples to increase sample sizes of subgroups are warranted.

Polymorphisms in FKBP5 are associated with increased recurrence of depressive episodes and rapid response to antidepressant treatment.

The stress hormone-regulating hypothalamic-pituitary-adrenal (HPA) axis has been implicated in the causality as well as the treatment of depression. To investigate a possible association between genes regulating the HPA axis and response to antidepressants and susceptibility for depression, we genotyped single-nucleotide polymorphisms in eight of these genes in depressed individuals and matched controls. We found significant associations of response to antidepressants and the recurrence of depressive episodes with single-nucleotide polymorphisms in FKBP5, a glucocorticoid receptor-regulating cochaperone of hsp-90, in two independent samples. These single-nucleotide polymorphisms were also associated with increased intracellular FKBP5 protein expression, which triggers adaptive changes in glucocorticoid receptor and, thereby, HPA-axis regulation. Individuals carrying the associated genotypes had less HPA-axis hyperactivity during the depressive episode. We propose that the FKBP5 variant-dependent alterations in HPA-axis regulation could be related to the faster response to antidepressant drug treatment and the increased recurrence of depressive episodes observed in this subgroup of depressed individuals. These findings support a central role of genes regulating the HPA axis in the causality of depression and the mechanism of action of antidepressant drugs.

Brain-derived neurotrophic factor Val66Met polymorphism and early life adversity affect hippocampal volume.

The interaction between adverse life events during childhood and genetic factors is associated with a higher risk to develop major depressive disorder (MDD). One of the polymorphisms found to be associated with MDD is the Val66MET polymorphism of brain-derived neurotrophic factor (BDNF). The aim of our two-center study was to determine how the BDNF Val66Met polymorphism and childhood adversity affect the volumetric measures of the hippocampus in healthy individuals and people with MDD. In this two-center study, 62 adult patients with MDD and 71 healthy matched controls underwent high-resolution magnetic resonance imaging. We used manual tracing of the bilateral hippocampal structure with help of the software BRAINS2, assessed childhood adversity using the Childhood Trauma Questionnaire and genotyped Val66Met BDNF SNP (rs6265). MDD patients had smaller hippocampal volumes, both in the left and right hemispheres (F = 5.4, P = 0.022). We also found a significant interaction between BDNF allele and history of childhood adversity (F = 6.1, P = 0.015): Met allele carriers in our samples showed significantly smaller hippocampal volumes when they did have a history of childhood adversity, both in patients and controls. Our results highlight how relevant stress-gene interactions are for hippocampal volume reductions. Subjects exposed to early life adversity developed smaller hippocampal volumes when they carry the Met-allele of the BDNF polymorphism.

Possible association between OPRM1 genetic variance at the 118 locus and alcohol dependence in a large treatment sample: relationship to alcohol dependence symptoms.

BACKGROUND: Several lines of evidence from previous research indicate that opioid receptors play an important role in ethanol reinforcement and alcohol dependence (AD) risk. Conflicting results were reported on the role of the mu-opioid receptor (OPRM1) polymorphism A118G (Asn40Asp, rs1799971) in the development of alcoholism. METHODS: We investigated a total number of 1,845 alcohol-dependent subjects recruited from inpatient facilities in Germany and 1,863 controls for the mu-opioid receptor (OPRM1) polymorphism using chi-square statistics. RESULTS: An association between the OPRM variant and AD was detected (p = 0.022), in recessive (AA vs. GA/GG) and co-dominant (AA vs. GA) models of inheritance. An association between the OPRM variant and the DSM-IV criterion "efforts to cut down or could not" (p = 0.047) was found, but this did not remain significant after the correction for multiple testing. CONCLUSIONS: The results indicate that this functional OPRM variant is associated with risk of AD and these findings apply to more severe AD, although the association is only nominally significant.

Lack of association between SNPs in the NEUROD2 gene and alcohol dependence in a German patient sample.

Results of a human post mortem study performed by our own group have suggested that the transcription factor NEUROD2, which plays a role in neuronal development, as well as in the development of anxiety and risk behavior in mice, might be a susceptibility factor for addictive disorders. Therefore the aim of the present study was to analyze a possible relation between genetic variants in the NEUROD2 gene and alcohol dependence in a sample of the Munich Gene Bank of Alcoholism (MGBA). We performed single SNP (single nucleotide polymorphism) and haplotype studies in 430 alcohol-dependent patients and 365 healthy controls with four SNPs covering the gene region of NEUROD2. Neither single SNP nor haplotype analysis could detect significant associations with alcohol dependence. Additionally we could not detect any relation of the analyzed genetic variants to Cloninger's Type 1/2 or Babor's Type A/B classification, to the age of onset or to the amount of alcohol intake. Our results do not provide evidence for an involvement of NEUROD2 polymorphisms in the pathophysiology of alcohol dependence. Further association studies are needed to confirm our findings.

Association of ADH4 genetic variants with alcohol dependence risk and related phenotypes: results from a larger multicenter association study.

Genetic variants of the alcohol-metabolizing enzyme ADH4, located on chromosome 4q22-4q23, have been related to alcohol dependence (AD) risk in previous research. The aim of this association study in a large multicenter sample of alcohol-dependent individuals and controls is to confirm ADH4 single nucleotide polymorphism (SNP) and haplotype association with AD and relevant related phenotypes. One thousand, six hundred and twenty-two (1622) inpatient subjects and 1469 control subjects with DSM-IV. AD from four addiction treatment centres were included. Characteristics of AD and related phenotypes including alcohol withdrawal, Cloninger's type I and II and first ages of drinking, regular drinking and AD onset were obtained using standardized structured interviews. After subjects were genotyped for 2 ADH4 polymorphisms, single SNP case-control and haplotype analyses were conducted. Both variants--rs1800759 and rs1042364--and the A-A and C-G haplotypes were significantly related to AD across samples. Furthermore, associations with AD-related phenotypes and subtypes revealed a potential protective influence of this haplotype. This study confirms the significant relationship of ADH4 variants with AD and related phenotypes. While the rs1800759 and rs1042364 A-A haplotype had a potential protective influence on the risk for several AD-related phenotypes, this effect is rather small compared to functional variants of other alcohol or acetaldehyde-metabolizing enzymes like ALDH2*2 or ADH1B*2.

Effects of mirtazapine on dehydroepiandrosterone-sulfate and cortisol plasma concentrations in depressed patients.

BACKGROUND: Among the neuroactive steroids, dehydroepiandrosterone sulfate (DHEA-S) is at least in part produced in the adrenal gland and is therefore under the control of the hypothalamic-pituitary-adrenocortical (HPA)-system. In the present study, the impact of mirtazapine on DHEA-S and cortisol (COR) levels was investigated in relation to clinical response in depressed patients. METHODS: A total of 23 inpatients suffering from a major depressive episode (DSM-IV criteria) underwent 5-week treatment with mirtazapine (45 mg/day). Plasma samples were taken weekly at 0800 h and quantified for COR and DHEA-S levels. RESULTS: Mirtazapine significantly reduced both COR and DHEA-S concentrations, but had no impact on the COR/DHEA-S ratio. The percentage decrease of DHEA-S, but not that of COR was significantly and positively correlated with the percentage reduction in the sum score of the Hamilton Depression Rating Scale at week 5, suggesting a relationship between DHEA-S reduction and clinical efficacy of mirtazapine. There was a significant positive correlation between the decline in COR and DHEA-S levels. CONCLUSIONS: Apparently, the decrease in COR and DHEA-S concentrations conjointly reflects an attenuating impact of mirtazapine on HPA axis activity, thereby decreasing the adrenal secretion of COR and DHEA-S.

No association of alcohol dependence with SLC6A5 and SLC6A9 glycine transporter polymorphisms.

To determine whether glycine transporter polymorphisms are associated with alcoholism, three genetic variants of SLC6A5 and two polymorphisms of SLC6A9 were genotyped in 463 German non-alcoholic controls and 644 German alcohol-dependent subjects. Association was investigated employing chi-square statistics and haplotype analysis. There was a significant association between the SLC6A5 polymorphism (rs1443547) and alcohol dependence as alcoholic individuals had a lower rate of AG-allele (chi(2) = 6.048, P = 0.049, d.f. = 2), which did not remain significant after correction for multiple testing. There was no association between SLC6A9 glycine transporter polymorphisms and alcohol dependence, and also none in haplotype analysis.

Enhanced serotonin transporter function during depression in seasonal affective disorder.

Decreased synaptic serotonin during depressive episodes is a central element of the monoamine hypothesis of depression. The serotonin transporter (5-HTT, SERT) is a key molecule for the control of synaptic serotonin levels. Here we aimed to detect state-related alterations in the efficiency of 5-HTT-mediated inward and outward transport in platelets of drug-free depressed patients suffering from seasonal affective disorder (SAD). 5-HTT turnover rate, a measure for the number of inward transport events per minute, and tyramine-induced, 5-HTT-mediated outward transport were assessed at baseline, after 4 weeks of bright light therapy, and in summer using a case-control design in a consecutive sample of 73 drug-free depressed patients with SAD and 70 nonseasonal healthy controls. Patients were drug-naive or medication-free for at least 6 months prior to study inclusion, females patients were studied in the follicular phase of the menstrual cycle. All participants were genotyped for a 5-HTT-promoter polymorphism (5-HTTLPR) to assess the influence of this polymorphism on 5-HTT parameters. Efficiency of 5-HTT-mediated inward (p=0.014) and outward (p=0.003) transport was enhanced in depressed patients. Both measures normalized toward control levels after therapy and in natural summer remission. Changes in outward transport showed a clear correlation with treatment response (rho=0.421, p=0.001). Changes in inward transport were mediated by changes in 5-HTT transport efficiency rather than affinity or density. 5-HTTLPR was not associated with any of the 5-HTT parameters. In sum, we conclude that the 5-HTT is in a hyperfunctional state during depression in SAD and normalizes after light therapy and in natural summer remission.

SNAP-25 gene polymorphisms and weight gain in schizophrenic patients.

Drug induced weight gain is a serious side effect of several atypical antipsychotics. As genetic factors play an important role in the homeostasis of hunger/satiety we tried to replicate a preliminary previous finding about an impact of three polymorphisms in the synaptosomal-associated protein of 25kDa (SNAP-25; sites MnlI, TaiI and DdelI in the 3(')-UTR) on clinical response and antipsychotic induced weight gain. We genotyped 162 schizophrenic patients being treated in monotherapy with atypical antipsychotics and 312 healthy control subjects for the three polymorphisms in the SNAP-25 gene using PCR. PANSS scores and weight were measured weekly for a minimum of five weeks. We found significant associations between the TaiI and MnlI polymorphisms and serum triglyceride levels at baseline and for the DdelI polymorphism and weight gain. In conclusion our study can at least partly replicate the previous findings concerning the impact of SNAP-25 gene polymorphisms on weight gain during antipsychotic treatment.

Association of the brain-derived neurotrophic factor Val66Met polymorphism with reduced hippocampal volumes in major depression.

CONTEXT: Brain-derived neurotrophic factor (BDNF) modulates hippocampal plasticity, which is believed to be altered in patients with major depression. OBJECTIVE: To examine the effect of the BDNF Val66Met polymorphism on hippocampal and amygdala volumes in patients with major depression and in healthy control subjects. DESIGN: Cross-sectional comparison between patients and controls. SETTING: Inpatients with major depression from the Department of Psychiatry and Psychotherapy and healthy controls from the community were recruited. PARTICIPANTS: The study population of 120 subjects included 60 patients with major depression and 60 healthy controls. MAIN OUTCOME MEASURES: Using a combined strategy, hippocampal and amygdala volumes were estimated on high-resolution magnetic resonance images, and genotyping was performed for the BDNF Val66Met polymorphism. RESULTS: Patients had significantly smaller hippocampal volumes compared with controls (P = .02). Significantly smaller hippocampal volumes were observed for patients and for controls carrying the Met-BDNF allele compared with subjects homozygous for the Val-BDNF allele (P = .006). With respect to amygdala volumes, no significant differences between patients and controls and no significant main effects for the BDNF Val66Met polymorphism were observed. CONCLUSIONS: These genotype-related alterations suggest that Met-BDNF allele carriers might be at risk to develop smaller hippocampal volumes and may be susceptible to major depression. This study supports findings from animal studies that the hippocampus is involved in brain development and plasticity.

Analysis of single nucleotide polymorphisms and haplotypes in the neuropeptide Y gene: no evidence for association with alcoholism in a German population sample.

BACKGROUND: Several lines of evidence from animal and electrophysiological studies indicate that the neuropeptide Y (NPY) gene is involved in the pathophysiology of alcohol dependence. Recent studies have provided evidence for an association between a Leu7Pro polymorphism, as well as 2 promoter single nucleotide polymorphisms (SNPs) in the NPY gene (G-602T, T-399C) and alcohol dependence. The aim of the present study was to analyze these variants in a large sample of the Munich Gene Bank of Alcoholism. METHODS: We performed single SNP and haplotype studies in 465 alcohol dependent patients and 448 healthy controls with 3 SNPs in the promoter region (-883ins/del, G-602T, T-399C) and the Leu7Pro polymorphism in exon 2 of the NPY gene. RESULTS: Neither single SNP-, nor haplotype analysis could detect significant associations with alcohol dependence. Additionally we could not detect any relation to Cloninger's Type 1/2 or Babor's Type A/B classification, to withdrawal symptoms, to the age of onset or to the amount of alcohol intake. CONCLUSIONS: In conclusion, our results suggest that the analyzed SNPs, as well as the corresponding haplotypes of the NPY gene are unlikely to play a major role in the pathophysiology of alcohol dependence in the investigated sample from the German population. Further analyses are needed to confirm the present results.

Paroxetine with pindolol augmentation: a double-blind, randomized, placebo-controlled study in depressed in-patients.

Pindolol, a 5-HT1A autoreceptor antagonist, given in combination with selective serotonin reuptake inhibitors (SSRIs), may enhance and/or accelerate the therapeutic efficacy of SSRIs. Fifty patients, meeting ICD-10 criteria for major depressive disorder or bipolar depression, were enrolled in our randomized, placebo-controlled, double-blind trial. One group received paroxetine plus pindolol (2.5 mg t.i.d.), and the other group received paroxetine plus placebo. The proportion of patients with sustained response (>or=50% reduction of baseline HAM-D 17 score maintained until the endpoint; p=0.252) and the proportion of patients with remission (HAM-D 17

Reduced hippocampal volumes associated with the long variant of the tri- and diallelic serotonin transporter polymorphism in major depression.

Substantial evidence supports a role for dysfunction of the serotonin transporter (5-HTT) in the pathogenesis of major depression. The polymorphism of the serotonin transporter gene (5-HTTLPR) was found to be associated with reduced hippocampal volume in major depression. However, the original diallelic polymorphism was criticized, because the L-allele can be subtyped into La and Lg alleles, the latter of which is thought to be similar to the S-allele. Therefore, the study aim was to examine the influences of the triallelic (La-Lg-S system) and diallelic 5-HTTLPR on hippocampal volumes in patients with major depression and healthy controls. Using high-resolution MRI hippocampal volumes and polymorphisms (5-HTTLPR) were measured in 60 in-patients with major depression and 60 healthy controls. Patients with the La/La genotype had significantly smaller hippocampal gray and white matter than La/La controls. No significant differences were found between patients and controls with La/(Lg + S) or (Lg + S)/(Lg + S) genotype. Moreover, within the patient group the La/La homozygous genotype had significantly smaller hippocampal white matter volumes than the La/(Lg + S) or (Lg + S)/(Lg + S) genotype. In conclusion, with the diallelic as well as the triallelic system the homozygosity for the long-allele is associated with decreased hippocampal volumes in patients with major depression, but not in healthy controls, suggesting that disease or stress specific processes linked to the serotonergic system may enhance the vulnerability to morphological alterations.

SNP- and haplotype analysis of the tryptophan hydroxylase 2 gene in alcohol-dependent patients and alcohol-related suicide.

Several lines of evidence indicate that disturbances of the central serotonergic system are involved in the pathophysiology of alcohol dependence and suicidal behavior. Recent studies have indicated that a newly identified second isoform of the tryptophan hydroxylase gene (TPH2) is preferentially involved in the rate limiting synthesis of neuronal serotonin. Genetic variations in the TPH2 gene have been associated with an increased risk for major depression and suicidal behavior. We performed single SNP (single nucleotide polymorphism), linkage disequilibrium and haplotype studies on 353 alcohol-dependent patients of whom 102 individuals had a history of at least one suicide attempt and 305 healthy controls with 20 SNPs covering the entire gene region of TPH2. Neither single SNP-, nor haplotype analysis could detect significant associations with alcohol dependence and/or suicidal behavior among alcohol-dependent patients. One major haplotype block of strong linkage disequilibrium between introns 5 and 8 of the TPH2 gene has been found in alcoholics and controls, which is in concordance with recent reports. In conclusion, our results suggest that single SNPs, respectively, haplotypes of the TPH2 gene are unlikely to play a major role in the pathophysiology of alcohol dependence or the alcoholism-related phenotype suicidal behavior. Further analysis are needed to confirm these results.

Analysis of tryptophan hydroxylase I and II mRNA expression in the human brain: a post-mortem study.

Dysregulation of brain serotonin transmission is an important contributing factor in many psychiatric disorders. Tryptophan hydroxylase (TPH), the rate limiting enzyme in the biosynthesis of serotonin plays a major role as candidate gene in several psychiatric disorders. Recently, a second TPH isoform (TPH2) was identified in mice which was exclusively expressed in the brain. Due to the lack of data about its anatomic expression in humans we performed a mRNA expression analysis comparing TPH1 and TPH2 mRNA in several regions of the human brain (cortex, thalamus, hypothalamus, hippocampus, amygdala, cerebellum and raphe nuclei). The study was performed with post-mortem specimens obtained from eight individuals with sudden deaths, not directly involving CNS diseases. Our results demonstrate that the mRNA of both genes is expressed in each investigated brain region with variations between the brain areas, as well as between the particular genes. The major finding of this study was the high expression level of TPH2 mRNA in the raphe nuclei ( approximately 4-fold more abundant than that of TPH1). The raphe nuclei showed the highest TPH2 mRNA levels at all, compared to the other regions (7-fold higher levels on average). To our knowledge, this is the fist study which demonstrates the localization of TPH1 and TPH2 mRNA in different regions of the human brain. Our findings provide further support for a duality of the serotonergic system and may open up new research strategies for the analysis of the repeatedly observed disturbances in the serotonergic system in patients suffering from several psychiatric disorders.