Associated and intermediate factors between genetic variants of the dopaminergic D2 receptor gene and harmful alcohol use in young adults.

Dopamine receptor D2 (DRD2) and ankyrin repeat and kinase domain-containing protein 1 (ANKK1) genes have received considerable attention for their involvement in alcohol use disorder (AUD), but many questions remain on their exact role. We conducted a population-based case-control and genetic association study in a large sample of young adults. Our aim was to assess the association between DRD2 and ANKK1 single nucleotide polymorphisms (SNPs) and harmful alcohol use, disentangling associated and possible intermediate factors. A total of 1841 college students from the French region Champagne-Ardennes, aged between 18 and 21 years and who reported at least one lifetime alcohol consumption, were included in this study. Allele frequencies were analysed according to harmful alcohol use (assessed through the Alcohol Use Disorder Identification Test [AUDIT] questionnaire). Different substance use disorders, including nicotine and cannabis dependences, were also assessed through questionnaires, as was a list of potential associated factors (e.g., major depressive episode, conduct disorder, attention-deficit/hyperactivity disorder [ADHD], school failure, sugar consumption, sexual trauma, parents' use of alcohol, tobacco or cannabis). We found that DRD2 rs1800498 was associated with harmful alcohol use. Many factors were detected, but a global path analysis revealed that DRD2 rs1800498 had a significant direct effect on harmful alcohol use and that early age at first alcohol consumption and depressive symptoms moderated this effect. This study suggests an interplay between harmful alcohol use, DRD2 genotypes and other risk factors that, with a full understanding, could be useful for preventive purposes.

Self-consciousness impairments in schizophrenia with and without first rank symptoms using the moving rubber hand illusion.

INTRODUCTION: The moving rubber hand illusion allows the evaluation both the sense of body ownership and agency using visuo-motor stimulations. METHODS: We used the moving rubber hand illusion in anatomic congruence with explicit measures to compare active asynchronous and passive synchronous movements in patients diagnosed with schizophrenia with first rank symptoms (FRS) (n = 31) versus without FRS (n = 25). RESULTS: Patients with FRS are characterized by a lack of agency in active asynchronous condition. The two groups had no sense of ownership in synchronous passive condition. Using a multivariate regression model, we found an association between agency and body ownership measures in the active asynchronous condition in two groups (OR: 1.825, p < 0.001). In the passive condition, this association was only present in the group with first rank symptoms (OR: 2.04, p < 0.001). CONCLUSION: Temporal proximity and sensorimotor information are essential in the understanding of self-consciousness disorders in schizophrenia.

Lower leptin level at discharge in acute anorexia nervosa is associated with early weight-loss.

OBJECTIVE: Predictive values of acute phase metabolic abnormalities of anorexia nervosa (AN) have seldom been studied. As early postrestoration weight loss is associated with poor outcome, discharge biologic parameters were assessed to detect an association with 2-month follow-up weight loss as a proxy to poor outcome. METHOD: Fasting plasma levels of leptin, acyl-ghrelin, obestatin, PYY, oxytocin and BDNF were measured in 26 inpatients, at inclusion, at discharge and 2 months later. A body mass index less than 18 2-month postdischarge was considered a poor outcome. RESULTS: Nineteen patients (73%) had a fair outcome and seven (27%) had a poor one with a mean loss of 0.69 versus 4.54 kg, respectively. Only discharge leptin levels were significantly higher in fair versus poor outcome patients (14.1 vs. 7.0 ng/ml, p = 0.006). The logistic regression model using discharge leptin, acyl-ghrelin, obestatin, oxytocin, PYY and BDNF levels as predictors of outcome disclosed a nearly significant effect of leptin (p < 0.10). Receiver operating characteristic analysis showed 11.9 ng/ml was the best value of threshold. Neither clinical variables differed according to outcome. CONCLUSION: Leptin level may be a biomarker of early weight relapse after acute inpatient treatment of AN. Its clinical usefulness in monitoring care in AN should further be determined.

De novo deleterious variants that may alter the dopaminergic reward pathway are associated with anorexia nervosa.

PURPOSE: Anorexia nervosa (AN) is a complex neuropsychiatric disorder presenting with dangerously low body weight, and a deep and persistent fear of gaining weight. Up to now, four genome-wide association studies of AN have been conducted to date and identified only few significant loci. However, both previous studies focused on common variation and on rare exonic variants. Currently, de novo variants are one of the most significant risk factors for neurodevelopmental disorders and psychiatric disorders. METHODS: We analyzed by whole exome sequencing a cohort of nine female AN individuals and their parents (mother and father), and focused our analysis on de novo variants. RESULTS: Here, we found seven de novo missense variants in potential genes in nine studied AN patients. Four of these genes (CSMD1, CREB3, PTPRD and GAB1) belong to a same signaling pathway involving neuron differentiation and dopamine pathway. CONCLUSIONS: This study provides a list of interesting genes such as CSDM1 and CREB3 that are candidates to be involved in the etiology of anorexia nervosa. LEVEL OF EVIDENCE: basic research.

Exome sequencing in a familial form of anorexia nervosa supports multigenic etiology.

Anorexia nervosa (AN) is a severe debilitating eating disorder. To date, only very few genes that predispose to AN have been identified. An alternative to association studies is to characterize ultra-rare variants in familial forms of AN. Here, we have implemented this approach to identify pathways that contribute to the development of AN through the analysis of a family with three members suffering from AN by exome analysis. We identified three ultra-rare deleterious variants in three genes (DRD4, CCKAR, NMS), already connected to the reward pathway, that co-segregate with AN, suggesting that this pathway might be playing a predisposing role in AN at least in familial forms.

Netrin G1: its downregulation in the nucleus accumbens of cocaine-conditioned mice and genetic association in human cocaine dependence.

Netrin G1 is a presynaptic ligand involved in axonal projection. Although molecular mechanisms underlying cocaine addiction are still poorly understood, Netrin G1 might have a role as a regulator of anxiety, fear and spatial memory, behavioural traits impaired in the context of cocaine exposure. In this study, the Netrin G1 (Ntng1) expression was investigated in the nucleus accumbens of mice primarily conditioned to cocaine using a place preference paradigm. A genetic association study was then conducted on 146 multiplex families of the Collaborative study on Genetics of Alcoholism, in which seven single nucleotide polymorphisms located in the NTNG1 gene were genotyped. NTNG1 expression levels were also quantified in BA10, BA46 and the cerebellum of healthy controls (with no Axis 1 psychopathology). Decreased Ntng1 expression was initially observed in the nucleus accumbens of mice conditioned to cocaine. Significant genetic family-based associations were detected between NTNG1 polymorphisms and cocaine dependence. NTNG1 expression in BA10, BA46 and the cerebellum, however, were not significantly associated with any allele or haplotype of this gene. These results confirm that Ntng1 expression is disturbed in the nucleus accumbens of mice, after cocaine conditioning. A haplotype of NTNG1 was found to constitute a vulnerability factor for cocaine use disorder in patients, although none of its single nucleotide polymorphisms were associated with a differential expression pattern in healthy controls. The data suggest that change in the Ntng1 expression is a consequence of cocaine exposure, and that some of its genetic markers are associated with a greater risk for cocaine use disorder.

Determinants of Blood Brain-Derived Neurotrophic Factor Blood Levels in Patients with Alcohol Use Disorder.

BACKGROUND: Blood brain-derived neurotrophic factor (BDNF) levels are influenced by both addiction and mood disorders, as well as somatic conditions, gender, and genetic polymorphisms, leading to widely varying results. Depressive symptoms and episodes are frequently observed in patients with alcohol use disorder, and vary widely over time, making it a challenge to determine which aspects are specifically involved in variations of serum BDNF levels in this population. METHODS: We assessed 227 patients with alcohol dependence involved in a detoxification program, at baseline and after a follow-up of 6 months, for the Alcohol Use Disorders Identification Test score, the length of alcohol dependence, and the number of past detoxification programs. The Beck Depression Inventory and information on current tobacco and alcohol use, suicidal ideation, body mass index, age, gender, and psychotropic treatments were also collected. Serum BDNF (ELISA) and 2 genetic polymorphisms of the BDNF gene (Val33Met and rs962369) were analyzed. RESULTS: The presence of the Met allele, 2 markers of the history of alcohol dependence (gamma glutamyl transferase and the number of past treatments in detoxification programs), and the presence of a depressive episode (but not depressive score) were significantly associated with the 2 blood levels of BDNF at baseline and after 6 months. After controlling for baseline BDNF levels, the presence of the Met allele and an ongoing depressive episode were the only variables associated with changes in BNDF levels after 6 months. CONCLUSIONS: Low serum BDNF levels are associated with characteristics related to alcohol consumption and mood disorders, and variants of the BDNF gene in alcohol use disorder patients. The factors that most strongly influenced changes in serum BDNF levels following treatment in an alcohol detoxification program were variants of the BDNF gene and ongoing depression.

Heavy cannabis use prior psychosis in schizophrenia: clinical, cognitive and neurological evidences for a new endophenotype?

Cannabis use is associated with an increased risk of schizophrenia, and is considered to impact late neurodevelopment. Neurological soft signs (NSS) associated with schizophrenia are considered as markers of early neurodevelopmental impairment. Our study examines the association between heavy cannabis use before the onset of psychosis and clinical, neuropsychological and neurological symptoms, including NSS. In a cross-sectional study, we consecutively included 61 patients with schizophrenia (34 reporting heavy cannabis use before the onset of psychosis and 27 not reporting such use), in the setting of a University Hospital and a Medical Center. Symptoms assessment and substance use disorder were evaluated with the Diagnostic Interview for Genetic Studies. NSS were assessed with the Neurological Evaluation Scale. Psychopathology was assessed with the Positive and Negative Symptom Scale. All patients underwent a battery of neurocognitive tests evaluating attention, memory and executive functions domains. Patients with heavy cannabis use before the onset of psychosis showed significantly less NSS (p < 0.05), less negative symptoms (p < 10-3) and a better cognitive functioning in different domains [median reaction time (p = 0.03), episodic memory (p = 0.04), visuoconstructive praxs (p = 0.03) than their non-heavy user counterparts]. Confounding effects of alcohol and tobacco were taken into account. Age and gender were not statistically different between the two groups (p = 0.70 and p = 0.16, respectively). Our study supports the clinical, neuropsychological and neurological specificity associated with the heavy use of cannabis before the onset of schizophrenia. Patients with heavy cannabis use before the onset of schizophrenia may exhibit later neurodevelopmental impairment than those who do not report such use. Schizophrenia associated with heavy cannabis use could represent a specific phenotype.

Neurotrophin Genes and Antidepressant-Worsening Suicidal Ideation: A Prospective Case-Control Study.

BACKGROUND: Antidepressant-worsening suicidal ideation is a rare but serious phenomenon. This study aimed to test for association between antidepressant-worsening suicidal ideation and polymorphisms of BDNF/NTRK2 neurotrophin pathway genes, known to be involved in depression and suicide. METHODS: This was a case-control study comparing patients with antidepressant-worsening suicidal ideation to patients without. Patients were collected from the GENESE cohort (3771 depressed tianeptine-treated outpatients). Antidepressant-worsening suicidal ideation was defined by an increase of at least 2 points on the Montgomery-Åsberg Depression Rating Scale-item10 during treatment. Controls were matched for age, sex, and baseline Montgomery-Åsberg Depression Rating Scale-item10 score. Thirteen single nucleotide polymorphisms covering 5 BDNF/NTRK2 pathway genes were genotyped. RESULTS: A total 78 cases and 312 controls were included. Two NTRK2 single nucleotide polymorphisms were associated to antidepressant-worsening suicidal ideation: rs1439050 (P=.01) and rs1867283 (P=.04). Association with rs1439050 remained significant after adjustment for potentially confounding factors, including previous suicide attempts (P<.01). CONCLUSIONS: This naturalistic prospective study is consistent with previous studies on highlighting the potential role of the neurotrophin pathway, and especially of NTRK2, in antidepressant-worsening suicidal ideation.

[A genetic view of addiction]. / Les addictions sous l'angle de la génétique.

The genetic analyses of addictions recently converted to genome-wide association studies (GWAS) and thanks to national and international consortia, allowed to recruit large cohorts of patients. This approach allowed the identification of the first susceptibility gene in addiction (tobacco), with genes CHRNA5, CHRNA3 and CHRNB4 encoding the α5, α3 and b4 subunits involved in the formation of nicotinic receptors, explaining 14% of the attributable risk for tobacco dependence. Variants of ADH1B and ADH1C genes encoding alcohol dehydrogenases enzymes have also been consistently associated, this time with alcohol dependence (AD). Finally, DRD2 and ANKK1 genes, involved in the dopaminergic pathway, and which were initially associated with AD, are now considered to be involved in a broader phenotype (addiction to psychoactive substances) including opiates. Future directions in molecular study of addiction are gene x environment interactions though the epigenetic approach. Numerous studies already investigated the methylome in addiction, including histone and microRNA modifications.

iPSC-derived models for anorexia nervosa research.

Anorexia nervosa (AN) is a complex neuropsychiatric disorder with genetic and epigenetic components that results in reduced food intake combined with alterations in the reward-processing network. While studies of patient cohorts and mouse models have uncovered genes and epigenetic changes associated with the disease, neuronal networks and brain areas preferentially activated and metabolic changes associated with reduced food intake, the underlying molecular and cellular mechanisms remain unknown. The use of both 2D in vitro cultures and 3D models, namely organoids and spheroids, derived from either human embryonic stem cells (ESCs) or induced pluripotent stem cells (iPSCs), would allow identification of cell type-specific changes associated with AN and comorbid diseases, to study preferential connections between brain areas and organs, and the development of therapeutic strategies.

The value of plasma cell-free DNA levels as biomarker in patients with eating disorders: A preliminary study.

OBJECTIVE: Circulating cell-free DNA (cfDNA) holds promise as a rapid and convenient biomarker for identifying individuals with eating disorders. To investigate this hypothesis, we measured plasma cfDNA in patients with different eating disorders. METHODS: In this study, 110 participants (98 patients with eating disorders divided into 30 patients with bulimia nervosa, 33 patients with anorexia nervosa (AN) Restricting subtype, 35 patients with AN Binge-eating/purging subtype and 12 controls) were enrolled. We measured both cell-free nuclear DNA (cf-nDNA) and cell-free mitochondrial DNA (cf-mtDNA) from plasma using two specific droplet digital PCR assays each, referring to two amplicon sizes. RESULTS: Levels of plasma cf-nDNA and cf-mtDNA showed no significant differences between control participants and those with eating disorders. However, we observed a higher proportion of long cf-nDNA fragments in patients with eating disorders, suggesting its potential as a biomarker for eating disorders. CONCLUSION: This is the first study of cfDNA in patients with eating disorders. Our findings highlight the potential for qualitative exploration of cfDNA, although not of quantitative interest. Full characterization of cfDNA may serve as a valuable biomarker for eating disorders and provide some insights into the hidden mechanisms underlying the chronic development of these conditions. Future studies are needed to confirm or refute this hypothesis.

The capacity of cognitive tests to detect generalized anxiety disorder (GAD): A pilot study.

Cognitive impairment remains understudied in generalized anxiety disorder (GAD), despite the high prevalence and substantial burden associated with this disorder. We aimed to assess cognitive impairment in patients with GAD and evaluate the ability of cognitive tests to detect this disorder. Because of its high rate of comorbidity, we also examined how other anxiety disorders and current major depressive episodes affected our results. We tested 263 consecutive general practice outpatients. We used the GAD-7 and the Mini International Neuropsychiatric Interview (MINI) to detect anxiety and mood disorders. We assessed cognitive performance with the Stroop test, a facial emotion recognition test, and the trail-making test (TMT). Compared to patients without GAD, patients with GAD were significantly slower to complete the TMT(B-A) and faster to recognize emotions, especially negative ones such as disgust and anger. When controlling for other anxiety disorders and current major depressive episode, GAD retained a significant effect on the TMT(B-A), but not on the emotion recognition test. The TMT(B-A) could detect GAD with good accuracy (area under the curve (AUC) = 0.83, maximal Youden's index = 0.56), which was by no means comparable to the GAD-7 (AUC = 0.97, Youden's index = 0.81). While it is not efficient enough to replace the GAD-7 as a diagnostic tool, the capacity of the TMT(B-A) to detect GAD emphasizes the importance of cognitive flexibility impairment in GAD.

Assessing biomarkers of remission in female patients with anorexia nervosa (REMANO): a protocol for a prospective cohort study with a nested case-control study using clinical, neurocognitive, biological, genetic, epigenetic and neuroimaging markers in a French specialised inpatient unit.

BACKGROUND: Anorexia nervosa (AN) is a severe psychiatric disorder associated with frequent relapses and variability in treatment responses. Previous literature suggested that such variability is influenced by premorbid vulnerabilities such as abnormalities of the reward system. Several factors may indicate these vulnerabilities, such as neurocognitive markers (tendency to favour delayed reward, poor cognitive flexibility, abnormal decision process), genetic and epigenetic markers, biological and hormonal markers, and physiological markers.The present study will aim to identify markers that can predict body mass index (BMI) stability 6 months after discharge. The secondary aim of this study will be focused on characterising the biological, genetic, epigenetic and neurocognitive markers of remission in AN. METHODS AND ANALYSIS: One hundred and twenty-five (n=125) female adult inpatients diagnosed with AN will be recruited and evaluated at three different times: at the beginning of hospitalisation, when discharged and 6 months later. Depending on the BMI at the third visit, patients will be split into two groups: stable remission (BMI≥18.5 kg/m²) or unstable remission (BMI<18.5 kg/m²). One hundred (n=100) volunteers will be included as healthy controls.Each visit will consist in self-reported inventories (measuring depression, anxiety, suicidal thoughts and feelings, eating disorders symptoms, exercise addiction and the presence of comorbidities), neurocognitive tasks (Delay Discounting Task, Trail-Making Test, Brixton Test and Slip-of-action Task), the collection of blood samples, the repeated collection of blood samples around a standard meal and MRI scans at rest and while resolving a delay discounting task.Analyses will mainly consist in comparing patients stabilised 6 months later and patients who relapsed during these 6 months. ETHICS AND DISSEMINATION: Investigators will ask all participants to give written informed consent prior to participation, and all data will be recorded anonymously. The study will be conducted according to ethics recommendations from the Helsinki declaration (World Medical Association, 2013). It was registered on clinicaltrials.gov on 25 August 2020 as 'Remission Factors in Anorexia Nervosa (REMANO)', with the identifier NCT04560517 (for more details, see https://clinicaltrials.gov/ct2/show/record/NCT04560517). The present article is based on the latest protocol version from 29 November 2019. The sponsor, Institut National de la Santé Et de la Recherche Médicale (INSERM, https://www.inserm.fr/), is an academic institution responsible for the monitoring of the study, with an audit planned on a yearly basis.The results will be published after final analysis in the form of scientific articles in peer-reviewed journals and may be presented at national and international conferences. TRIAL REGISTRATION NUMBER: clinicaltrials.govNCT04560517.

Mutations in two adjacent novel genes are associated with epidermodysplasia verruciformis.

Epidermodysplasia verruciformis (OMIM 226400) is a rare autosomal recessive genodermatosis associated with a high risk of skin carcinoma that results from an abnormal susceptibility to infection by specific human papillomaviruses (HPVs). We recently mapped a susceptibility locus for epidermodysplasia verruciformis (EV1) to chromosome 17q25. Here we report the identification of nonsense mutations in two adjacent novel genes, EVER1 and EVER2, that are associated with the disease. The gene products EVER1 and EVER2 have features of integral membrane proteins and are localized in the endoplasmic reticulum.

A systematic literature review and meta-analysis of circulating nucleic acids as biomarkers in psychiatry.

Common mental disorders (CMDs) such as depression, anxiety and post-traumatic stress disorders account for 40% of the global burden of disease. In most psychiatric disorders, both diagnosis and monitoring can be challenging, frequently requiring long-term investigation and follow-up. The discovery of better methods to facilitate accurate and fast diagnosis and monitoring of psychiatric disorders is therefore crucial. Circulating nucleic acids (CNAs) are among these new tools. CNAs (DNA or RNA) can be found circulating in body biofluids, and can be isolated from biological samples such as plasma. They can serve as biomarkers for diagnosis and prognoses. They appear to be promising for disorders (such as psychiatric disorders) that involve organs or structures that are difficult to assess. This review presents an accurate assessment of the current literature about the use of plasma and serum cell-free DNA (cfDNA) as biomarkers for several aspects of psychiatric disorders: diagnosis, prognosis, treatment response, and monitor disease progression. For each psychiatric disorder, we examine the effect sizes to give insights on the efficacy of CNAs as biomarkers. The global effect size for plasma nuclear and mitochondrial cfDNA studies was generally moderate for psychiatric disorders. In addition, we discuss future applications of CNAs and particularly cfDNA as non-invasive biomarkers for these diseases.

BDNF CpG methylation and serum levels covary during alcohol withdrawal in patients with alcohol use disorder: A pilot study.

OBJECTIVES: Brain-derived neurotrophic factor (BDNF) levels vary in various conditions including alcohol use disorder (AUD). We aimed to identify drivers of these variations. METHODS: Twelve patients with AUD were assessed at hospitalisation for alcohol withdrawal and four months later. We looked for associations between the change in serum BDNF levels and (1) length of abstinence, (2) anxiety (Hamilton Anxiety Scale) and depression (Beck-Depression Inventory), (3) one functional BDNF genotype (rs6265) and (4) methylation levels of 12 CpG sites within the BDNF gene (located in exons I, IV and IX). RESULTS: While abstinence remained, serum BDNF level increased. This increase correlated with the variation of methylation levels of the BDNF gene, and more specifically of exon I. We found no significant effect of length of abstinence, rs6265, depression or anxiety on serum BDNF level. CONCLUSIONS: Epigenetic regulation of the BDNF gene may be involved in variations of BDNF blood level associated with alcohol abstinence.

Chronic food restriction in mice and increased systemic ghrelin induce preference for running wheel activity.

OBJECTIVES: In eating disorders, particularly anorexia nervosa (AN), patients exhibit intense physical activity which is inappropriate regarding food restriction and chronic undernutrition, and exacerbates weight loss and energy deprivation. Rodent models of food restriction exhibit increased running wheel activity in the food anticipation period, also known as Food Anticipatory Activity (FAA). FAA probably has various physiological and/or neurobiological origins. Plasma concentrations of the orexigenic hormone ghrelin are, for example, increased during FAA. We hypothesize that the drive for physical activity in chronic food restriction is triggered by metabolic factors but also relies on motivational aspects that we aim to decipher in this study. METHODS: Young female C57Bl6/J mice were exposed to a paradigm based on a progressive 50% quantitative food restriction alone (FR) or associated with running wheel activity (Food Restriction Wheel: FRW) in their home-cage during 15 days. We measured preference for running wheel in a three-chamber apparatus in which animals could choose to explore either a known running wheel or a novel object. Testing took place either during resting or during FAA. We calculated the time spent in each compartment and the activity in running wheels. After progressive refeeding over 10 days, mice were tested again when refed. Plasma levels of both ghrelin isoforms were measured with selective immunoassays. RESULTS: When tested during FAA period, food restricted mice displayed increased preference for the running wheel compared to ad libitum fed controls. Both FR and FRW mice exhibited increased running time and distance in the wheel and running distance was correlated with ghrelin levels. Similar preference and behavior were found when testing took place during the resting period. Animals housed without an active wheel also exhibited active running. Progressive refeeding resulted in body weight restoration, a decrease in FAA and completely abolished preference for the running wheel. Refed animals displayed similar behavior as ad libitum fed controls. CONCLUSIONS: These data provide evidence that food restriction-induced physical activity is closely correlated with metabolic adaptations to nutritional status implicating ghrelin in the quantity of physical activity.

The role of dysregulated ghrelin/LEAP-2 balance in anorexia nervosa.

LEAP-2 is a ghrelin antagonist with an anorexigenic drive. This study investigates the evolution of plasma ghrelin and LEAP-2 concentrations in 29 patients with anorexia nervosa (AN) before and after refeeding and compares it to physiological adaptations during fasting in healthy controls or to mouse model of chronic food restriction and refeeding. Acute and chronic food restriction decrease LEAP-2 and increase ghrelin concentrations in both humans and mice, while patients with AN displayed higher ghrelin and LEAP-2 concentrations before than after refeeding (p = 0.043). After 6 months follow-up, patients with unstable weight gain (n = 17) had significantly decreased LEAP-2 concentrations after refeeding (p = 0.044), in contrast to patients with stable weight gain (n = 12). We provide evidence that the ghrelin/LEAP-2 system is not regulated according to the nutritional status in AN, in contrast to what is physiologically expected when coping with food restriction.