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Cigarette smoking is a severe health burden being related to a number of chronic diseases. Frequently, smokers report about sleep problems. Sleep disturbance, in turn, has been demonstrated to be involved in the pathophysiology of several disorders related to smoking and may be relevant for the pathophysiology of nicotine dependence. Therefore, determining the frequency of sleep disturbance in otherwise healthy smokers and its association with degree of nicotine dependence is highly relevant. In a population-based case-control study, 1071 smokers and 1243 non- smokers without lifetime Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Axis I disorder were investigated. Sleep quality (SQ) of participants was determined by the Pittsburgh Sleep Quality Index. As possible confounders, age, sex and level of education and income, as well as depressiveness, anxiety, attention deficit hyperac- tivity, alcohol drinking behaviour and perceived stress, were included into multiple regression analyses. Significantly more smokers than non-smokers (28.1% versus 19.1%; P < 0.0001) demonstrated a disturbed global SQ. After con- trolling for the confounders, impaired scores in the component scores of sleep latency, sleep duration and global SQ were found significantly more often in smokers than non-smokers. Consistently, higher degrees of nicotine dependence and intensity of smoking were associated with shorter sleep duration. This study demonstrates for the first time an elevated prevalence of sleep disturbance in smokers compared with non-smokers in a population without lifetime history of psychiatric disorders even after controlling for potentially relevant risk factors. It appears likely that smoking is a behaviourally modifiable risk factor for the occurrence of impaired SQ and short sleep duration.

The aim of the present study was to examine neurocognitive function associated with chronic nicotine use. A total of 2163 healthy participants (1002 smokers, 1161 never-smoking controls) participated in a population-based case- control design.The main outcome measures were six cognitive domain factors derived from a neuropsychological test battery. In smokers, the battery was administered after controlled smoking of one cigarette. Analyses included age, sex and education as covariates. Results demonstrated small, but significant deficits in smokers for visual attention (P < 0.001) and cognitive impulsivity (P < 0.006), while verbal episodic memory, verbal fluency, verbal working memory, and Stroop-interference did not differ between groups. These attention/impulsivity deficits were also present in smokers with only a low amount of cigarette consumption. Lifetime nicotine use (pack-years) was not correlated with cognition in smokers. In conclusion, this study confirmed subtle and specific cognitive deficits in non-deprived smokers. The independence of these deficits from consumption intensity may argue for an a priori deficit of some cognitive abilities in smokers. These specific deficits may constitute intermediate phenotypes for genetic research on nicotine use.

Alcohol dependence (AD) is an important contributory factor to the global burden of disease. The etiology of AD involves both environmental and genetic factors, and the disorder has a heritability of around 50%. The aim of the present study was to identify susceptibility genes for AD by performing a genome-wide association study (GWAS). The sample comprised 1333 male in-patients with severe AD according to the Diagnostic and Statistical Manual of Mental Disorders, 4th edition, and 2168 controls. These included 487 patients and 1358 controls from a previous GWAS study by our group. All individuals were of German descent. Single-marker tests and a polygenic score-based analysis to assess the combined contribution of multiple markers with small effects were performed. The single nucleotide polymorphism (SNP) rs1789891, which is located between the ADH1B and ADH1C genes, achieved genome-wide significance [P = 1.27E-8, odds ratio (OR) = 1.46]. Other markers from this region were also associated with AD, and conditional analyses indicated that these made a partially independent contribution. The SNP rs1789891 is in complete linkage disequilibrium with the functional Arg272Gln variant (P = 1.24E-7, OR = 1.31) of the ADH1C gene, which has been reported to modify the rate of ethanol oxidation to acetaldehyde in vitro. A polygenic score-based approach produced a significant result (P = 9.66E-9). This is the first GWAS of AD to provide genome-wide significant support for the role of the ADH gene cluster and to suggest a polygenic component to the etiology of AD. The latter result may indicate that many more AD susceptibility genes still await identification.

Tobacco smoking is a major risk factor for most of the diseases leading in mortality. Nicotine dependence (ND), which sustains regular smoking, is now acknowledged to be under substantial genetic control with some environmental contribution. At present, however, genetic studies on ND are mostly conducted in populations that have been poorly characterized with regard to ND-related phenotypes for the simple reason that the respective populations were not primarily collected to study ND. The German multi-centre study 'Genetics of Nicotine Dependence and Neurobiological Phenotypes', which is funded by the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG) as part of the Priority Program (Schwerpunktprogramm) SPP1226: 'Nicotine-Molecular and Physiological Effects in CNS', was intended to overcome some of these inherent problems of current genetic studies of ND. The multi-centre study is a population-based case-control study of smokers and never-smokers (n = 2396). The study was unique worldwide because it was the first large-scale genetic study specifically addressing ND with the collection of a wide range of environmental, psychosocial and neurobiological phenotypes. Study design and major population characteristics with emphasis on risk prediction of smoking status were presented in this paper.

P50 gating is a major functional biomarker in research on schizophrenia and other psychiatric conditions with high smoking prevalence. It is used as endophenotype for studying nicotinic systems genetics and as surrogate endpoint measure for drug development of nicotinic agonists. Surprisingly, little is known about P50 gating in the general population and the relationship to smoking-related characteristics. In this multicenter study at six academic institutions throughout Germany, n = 907 never-smokers (NS

Breast cancer is the most frequent cancer type among women in western countries. In addition to established risk factors like hormone replacement therapy, oxidative stress may play a role in carcinogenesis through an unbalanced generation of reactive oxygen species that leads to genetic instability. The aim of this study is to assess the influence of common single nucleotide polymorphisms (SNPs) in candidate genes related to oxidative stress on postmenopausal breast cancer risk. We genotyped 109 polymorphisms (mainly tagging SNPs) in 22 candidate genes in 1,639 postmenopausal breast cancer cases and 1,967 controls (set 1) from the German population-based case-control study "MARIE". SNPs showing association in set 1 were tested in further 863 cases and 2,863 controls from MARIE (set 2) using a joint analysis strategy. Six polymorphisms evaluated in the combined set showed significantly modified breast cancer risk per allele in the joint analysis, including SNPs in CYBA (encoding a subunit of the NADPH oxidase: rs3794624), MT2A (metallothionein 2A: rs1580833), TXN (thioredoxin: rs2301241), and in TXN2 (thioredoxin 2: rs2267337, rs2281082, rs4821494). Associations with the CYBA rs3794624 (OR per allele: 0.93, 95% CI 0.87-0.99) and TXN rs2301241 variants (OR per allele: 1.05, 95% CI 1.00-1.10) were confirmed in the summary risk estimate analysis using up to three additional studies. We found some evidence for association of polymorphisms in genes of the thioredoxin system, CYBA, and MT2A with postmenopausal breast cancer risk. Summary evidence including independent datasets indicated moderate effects in CYBA and TXN that warrant confirmation in large independent studies.

Recent studies strongly support an association of the nicotinic acetylcholine receptor gene cluster CHRNA5-CHRNA3-CHRNB4 with nicotine dependence (ND). However, the precise genotype-phenotype relationship is still unknown. Clinical and epidemiological data on smoking behavior raise the possibility that the relevant gene variants may indirectly contribute to the development of ND by affecting cognitive performance in some smokers who consume nicotine for reasons of "cognition enhancement." Here, we tested seven single nucleotide polymorphisms (SNPs) rs684513, rs637137, rs16969968, rs578776, rs1051730, rs3743078, rs3813567 from the CHRNA5-CHRNA3-CHRNB4 gene cluster for association with ND, measures of cognitive performance and gene expression. As expected, we found all SNPs being associated with ND in three independent cohorts (KORA, NCOOP, ESTHER) comprising 5,561 individuals. In an overlapping sample of 2,186 subjects we found three SNPs (rs16969968, rs1051730, rs3743078) being associated with cognitive domains from the Wechsler-Adult-Intelligence Scale (WAIS-R)-most notably in the performance subtest "object assembly" and the verbal subtest "similarities." In a refined analysis of a subsample of 485 subjects, two of these three SNPs (rs16969968, rs1051730) were associated with n-back task performance/Continuous Performance Test. Furthermore, two CHRNA5 risk alleles (rs684513, rs637137) were associated with CHRNA5 mRNA expression levels in whole blood in a subgroup of 190 subjects. We here report for the first time an association of CHRNA5-CHRNA3-CHRNB4 gene variants with cognition possibly mediating in part risk for developing ND. The observed phenotype-genotype associations may depend on altered levels of gene expression. © 2010 Wiley-Liss, Inc.

Wagner S, Baskaya O, Anicker NJ, Dahmen N, Lieb K, Tadic A. The catechol o‐methyltransferase (COMT) val158met polymorphism modulates the association of serious life events (SLE) and impulsive aggression in female patients with borderline personality disorder (BPD). Objective: We analyzed i) the effects of serious life events (SLE) on impulsive aggression, and ii) modulating effects of the COMT Val158Met polymorphism on the association between SLEs and impulsive aggression in borderline personality disorder (BPD). Method: One hundred and twelve female BPD patients from Germany were included in this study. Impulsive aggression was assessed by the Buss‐Durkee‐Hostility Inventory (BDHI). Results: Childhood sexual abuse was associated with lower BDHI sum score (P = 0.003). In COMT Val158Val carriers, but not in Val/Met and Met/Met carriers, childhood sexual abuse and the cumulative number of SLEs were associated with lower BDHI sum scores (P Conclusion: This study analyzing a specific gene × environment interaction in female BPD patients suggests an association between SLEs and impulsive aggression, as well as a modulating effect of the COMT Val158Val genotype on the relation between SLEs and impulsive aggression.

Genetic factors contribute to the overall risk of developing nicotine addiction, which is the major cause of preventable deaths in western countries. However, knowledge regarding specific polymorphisms influencing smoking phenotypes remains scarce. In the present study we provide evidence that a common single nucleotide polymorphism (SNP) in the 5′ untranslated region of CHRM2, the gene coding for the muscarinic acetylcholine receptor 2 is associated with nicotine addiction. CHRM2 was defined as a candidate gene for nicotine addiction based on previous evidence that linked variations in CHRM2 to alcohol and drug dependence. A total of more than 5,500 subjects representative of the German population were genotyped and assessed regarding their smoking habits. The impact of three SNPs in CHRM2 on smoking behavior/nicotine addiction was investigated using logistic regression models or a quasi-Poisson regression model, respectively. We found the T allele of SNP rs324650 to be associated with an increased risk of smoking/nicotine dependence according to three different models, the recessive models of regular or heavy smokers vs. never-smokers (odds ratio 1.17 in both analyses) and according to the Fagerstrom index of nicotine addiction. In the analysis stratified by gender this association was only found in females. Our data provide further evidence that variations in CHRM2 may be associated with the genetic risk of addiction in general or with certain personality traits that predispose to the development of addiction. Alternatively, variations in CHRM2 could modulate presynaptic auto-regulation in cholinergic systems and may thereby affect an individual's response to nicotine more specifically. © 2009 Wiley-Liss, Inc.

Borderline personality disorder (BPD) is characterized by a heterogeneous symptomatology with instability in impulse control, interpersonal relationships and self-image. BPD patients display repeated self-injury, chronic suicidal tendencies and emotional dysregulation, mainly dysregulation of negative affect. In its etiology, genetic and environmental factors have been suggested. Recently, an investigation in male healthy volunteers found gene–gene effects of the catechol-O-methyl-transferase (COMT) low-activity (Met158) and the low-expression allele of the deletion/insertion (short/long or S/L, respectively) polymorphism in the serotonin transporter-linked promoter region (5-HTTLPR) on the central processing of aversive stimuli. The purpose of the present study was to test for association between BPD and the COMT Val158Met single nucleotide polymorphism (SNP), the 5-HTTLPR S/L variant and the interaction of these two gene variants. One hundred sixty one well-defined Caucasian BPD patients and 156 healthy controls were recruited from central Germany. In BPD patients, the genotype COMT Met158Met was over-represented compared to healthy controls (P = 0.0085; adjusted P = 0.034). We observed no differences in 5-HTTLPR genotypes between BPD and controls (P = 0.286). Additionally, the COMT Met158Met genotype was significantly over-represented in BPD patients carrying at least one 5-HTTLPR S allele (P = 0.0007; adjusted P = 0.028). Logistic regression analysis confirmed an interaction of the COMT Met158 and the 5-HTTLPR S allele (P = 0.001). These data suggest an involvement of altered dopaminergic and/or noradrenergic neurotransmission as well as an interactive effect of COMT and 5-HTTLPR gene variants in the etiology of BPD, and underline the usefulness of analyses of gene–gene effects in diseases of complex inheritance with multiple genes involved. © 2008 Wiley-Liss, Inc.

Risks from electromagnetic devices are of considerable concern. Electrohypersensitive (EHS) persons attribute a variety of rather unspecific symptoms to exposure to electromagnetic fields. The pathophysiology of EHS is unknown and therapy remains a challenge. We hypothesized that some electrosensitive individuals are suffering from common somatic health problems. Toward this end we analysed clinical laboratory parameters including thyroid-stimulating hormone (TSH), alanine transaminase (ALT), aspartate transaminase (AST), creatinine, hemoglobine, hematocrit and c-reactive protein (CRP) in subjects suffering from EHS and in controls that are routinely used in clinical medicine to identify or screen for common somatic disorders. One hundred thirty-two patients (n = 42 males and n = 90 females) and 101 controls (n = 34 males and n = 67 females) were recruited. Our results identified laboratory signs of thyroid dysfunction, liver dysfunction and chronic inflammatory processes in small but remarkable fractions of EHS sufferers as potential sources of symptoms that merit further investigation in future studies. In the cases of TSH and ALT/AST there were significant differences between cases and controls. The hypotheses of anaemia or kidney dysfunction playing a major role in EHS could be unambiguously refuted. Clinically it is recommended to check for signs of treatable somatic conditions when caring for individuals suffering from self-proclaimed EHS.

This study investigated the possible association of the MAOA T941G gene variant with differential antidepressant response to mirtazapine and/or paroxetine in 102 patients with major depression (DSM-IV criteria) participating in a randomized double-blind controlled clinical trial. Female mirtazapine-treated patients homozygous for the T-allele had a significantly faster and better treatment response than TG/GG-patients. In males, we failed to show an association between MAOA T941G gene variant and mirtazapine response. In the paroxetine-treated group, there were no significant differences in treatment response between MAOA T941G genotype groups. Time course of response and antidepressant efficacy of mirtazapine, but not paroxetine, seem to be influenced in a clinically relevant manner by this allelic variation within the MAOA gene, at least in female patients. An independent replication of our finding is needed. If replicated, genotyping of this locus could become a promising tool to predict response to mirtazapine treatment in females suffering from major depression. © 2006 Wiley-Liss, Inc.

This study was conducted to detect a possible association of a T941G single nucleotide polymorphism (SNP) in the monoamine oxidase A (MAOA) gene with generalized anxiety disorder (GAD), panic disorder (PD), or major depression (MD). Fifty GAD patients (34 females and 16 males), 38 PD patients (21 females and 17 males), and 108 MD patients (80 females and 28 males) were included. The comparison group consisted of 276 (132 females and 144 males) unrelated healthy individuals. The 941T allele was over-represented in patients suffering from GAD (chi(2) = 6.757; df = 1; P < 0.01, not corrected for multiple testing) when compared to healthy volunteers. No association was observed in MD or PD. This is the first study specifically analyzing the MAOA G941T polymorphism in GAD and thus needs to be replicated in an independent sample. However, the results are in line with previous data suggesting an association between the MAOA locus and regulation of complex human behavior.

BACKGROUND: The presence of the A1 allele of the dopamine D2 receptor TaqI restriction fragment length polymorphism has been reported to be associated with an earlier age of onset of alcohol dependence as a marker for severity. METHODS: We tested this hypothesis with special regard to the definition of the age of onset of alcoholism in 243 patients with alcohol dependence, according to DSM-IV criteria assessed by the standardized interview Munchner Composite International Diagnostic Interview (M-CIDI), consecutively admitted for detoxification. Additionally, the Addiction Severity Index (ASI) was performed. The TaqIA polymorphism was amplified by polymerase chain reaction (PCR), and the PCR product was digested by the restriction enzyme TaqI. Patients were subsequently divided into an A1 (presence of at least one A1 allele, n = 88) and an A2 group (absence of an A1 allele, n = 155). The following criteria for different definitions of age of onset were used: (1) age of onset of the first occurring symptom necessary for the diagnosis of alcohol dependence according to M-CIDI; (2) age of onset of the last symptom of alcohol dependence according to M-CIDI; (3) age of onset of more than 3 drinking days per week on a regular basis according to ASI; (4) age of onset of more than 3 drinking days-of more than five drinks per drinking day-or at least one binge drinking episode per week on a regular basis according to ASI. RESULTS: The frequency of the A1 allele in our patient sample was 0.208. No statistically significant association between the A1 allele and the age of onset of alcoholism was found. The mean age of onset according to criterion 1 was 30.4 +/- 10.8 years for the A1 group and 30.2 +/- 10.2 years for the A2 group (p = 0.89); for criterion 2, it was 33.3 +/- 10.0 years for the A1 group and 33.9 +/- 10.2 years for the A2 group (p = 0.77); for criterion 3, it was 18.0 +/- 7.5 years for the A1 group and 18.1 +/- 6.1 years for the A2 group (p = 0.92); and for criterion 4, it was 22.3 +/- 9.7 years for the A1 group and 21.8 +/- 8.5 years for the A2 group (p = 0.76). CONCLUSIONS: No association was found between the A1 polymorphism and age at onset of alcohol dependence according to different specified criteria.

Menopausal hormone therapy (HT) is associated with increased breast cancer risk among postmenopausal women. Nuclear receptors are involved in steroid hormone- and xenobiotic-mediated signal transduction playing a crucial role in regulating gene expression. Therefore, variations within these genes may influence HT-associated breast cancer risk. We investigated 3,149 postmenopausal breast cancer patients and 5,489 controls from 2 German population-based case-control studies. Thirty-three polymorphisms selected on the basis of known or putative functional relevance located in ESR1, ESR2, PGR, PXR and AR were genotyped. Conditional logistic regression was used to assess multiplicative statistical interaction between polymorphisms and duration of estrogen-progestagen therapy and of estrogen monotherapy with regard to breast cancer risk assuming log-additive and codominant modes of inheritance. We observed an increased risk for women carrying short AR_(CAG) alleles of22 repeats associated with combined estrogen-progestagen therapy compared with those with long alleles (or =22 repeats) (p(interaction) = 0.03). Additionally, risk associated with combination therapy use was significantly modified by 2 PXR polymorphisms with reduction of risk effects in carriers of the minor PXR_rs6785049_G and PXR_rs1054191_A alleles (p(interaction) = 0.04 and 0.05, respectively). Variants in both ESR1 and ESR2 modified risk associated with estrogen monotherapy use. Higher risk were observed in homozygotes for the major ESR1_rs910416_T allele (p(interaction)0.01) and in homozygotes for the minor ESR2_rs1271572_T, major ESR2_rs4986938_G and minor ESR2_rs928554_G alleles (p(interaction) = 0.02, 0.05, 0.02, respectively). Risk effect modification by ESR1_rs910416 and AR_(CAG)n polymorphisms remained significant after correction for multiple testing. We conclude that genetic variants in nuclear receptor genes may modify HT-associated postmenopausal breast cancer risk.