Genetic determinants of antidepressant and antipsychotic drug response.

Today, more than 90% of inpatients hospitalized with Major Depression or Schizophrenia are treated with psychotropic drugs. Since none of the treatment options is causal, response rates are modest and the course of recovery is very heterogeneous. Genetic studies on the etiology and pathogenesis of major psychiatric disorders over the past decades have been largely unsuccessful. Likewise, genetic studies to predict response to psychopharmacological treatment have also not been particularly successful. In this project we have recruited 902 inpatients with ICD-10 diagnoses of schizophrenic ("F2 patients") or depressive disorders ("F3 patients"). The study assessed today's acute inpatient treatment regimens with up to 8 repeated measurements regarding the time course of recovery and adverse side effects. The genotyping included 100 candidate genes with genotypic patterns computed from 549 Single Nucleotide Polymorphisms (SNPs). To predict response to psychopharmacological treatment, we relied on a multidimensional approach to analyzing genetic diversity in combination with multilayer Neural Nets (NNs). Central to this new method were the "gene vectors" that (1) assessed the multidimensional genotypic patterns observed with genes; and (2) evaluated the correlations between genes. By means of these methods, we searched for combinations of multidimensional genotypic patterns that were characteristic of treatment responders while being rare among non-responders. The chosen method of approach provided a powerful technique to detail the complex structures of SNP data that are not detectable by conventional association methods. Molecular-genetic NNs enabled correct classification of 100% "non-responders", along with 94.7% correctly classified "responders" among the F2 patients, and 82.6% correctly classified "responders" among the F3 patients. The F2 and F3 classifiers were not disjoint but showed an overlap of 29.6% and 35.7% between the diagnostic groups, thus indicating that clinical diagnoses may not constitute etiologic entities. Our results suggested that patients may have an unspecific physical-genetic disposition that enables, facilitates, impedes or prevents recovery from major psychiatric disorders by setting various thresholds for exogenous triggers that initiate improvement ("recovery disposition"). Even though this disposition is not causally linked to recovery, it can nonetheless be clinically used in the sense of a "surrogate". Indeed, clinicians are also interested in reliable tools that can "do the job", despite the fact that etiology and pathogenesis of the treated disorders remain unknown.

Contribution of Rare and Potentially Functionally Relevant Sequence Variants in Schizophrenia Risk-Locus Xq28,distal.

Duplications of the Xq28,distal locus have been described in male and female patients with schizophrenia (SCZ) or intellectual disability. The Xq28,distal locus spans eight protein-coding genes (F8, CMC4, MTCP1, BRCC3, VBP1, FUNDC2, CLIC2, and RAB39B) and is flanked by recurrent genomic breakpoints. Thus, the issue of which gene/s at this locus is/are relevant in terms of SCZ pathogenesis remains unclear. The aim of this study was to investigate the contribution of rare and potentially functionally relevant sequence variants within the Xq28,distal locus to SCZ risk using the single-molecule molecular inversion probes (smMIP) method. Targeted sequencing was performed in a cohort of 1935 patients with SCZ and 1905 controls of European ancestry. The consecutive statistical analysis addressed two main areas. On the level of the individual variants, allele counts in the patient and control cohort were systematically compared with a Fisher's exact test: (i) for the entire present study cohort; (ii) for patients and controls separated by sex; and (iii) in combination with data published by the Schizophrenia Exome Meta-Analysis (SCHEMA) consortium. On the gene-wise level, a burden analysis was performed using the X-chromosomal model of the Optimal Unified Sequence Kernel Association Test (SKAT-O), with adjustment for possible sex-specific effects. Targeted sequencing identified a total of 13 rare and potentially functional variants in four patients and 11 controls. However, neither at the level of individual rare and potentially functional variants nor at the level of the eight protein-coding genes at the Xq28,distal locus was a statistically significant enrichment in patients compared to controls observed. Although inconclusive, the present findings represent a step toward improved understanding of the contribution of X-chromosomal risk factors in neuropsychiatric disorder development, which is an underrepresented aspect of genetic studies in this field.

Prediction of clinical diagnosis of Alzheimer's disease, vascular, mixed, and all-cause dementia by a polygenic risk score and APOE status in a community-based cohort prospectively followed over 17 years.

The strongest genetic risk factor for Alzheimer's disease (AD) is the ε4 allele of Apolipoprotein E (APOE) and recent genome-wide association meta-analyses have confirmed additional associated genetic loci with smaller effects. The aim of this study was to investigate the ability of an AD polygenic risk score (PRS) and APOE status to predict clinical diagnosis of AD, vascular (VD), mixed (MD), and all-cause dementia in a community-based cohort prospectively followed over 17 years and secondarily across age, sex, and education strata. A PRS encompassing genetic variants reaching genome-wide significant associations to AD (excluding APOE) from the most recent genome-wide association meta-analysis data was calculated and APOE status was determined in 5203 participants. During follow-up, 103, 111, 58, and 359 participants were diagnosed with AD, VD, MD, and all-cause dementia, respectively. Prediction ability of AD, VD, MD, and all-cause dementia by the PRS and APOE was assessed by multiple logistic regression and receiver operating characteristic curve analyses. The PRS per standard deviation increase in score and APOE4 positivity (≥1 ε4 allele) were significantly associated with greater odds of AD (OR, 95% CI: PRS: 1.70, 1.45-1.99; APOE4: 3.34, 2.24-4.99) and AD prediction accuracy was significantly improved when adding the PRS to a base model of age, sex, and education (ASE) (c-statistics: ASE, 0.772; ASE + PRS, 0.810). The PRS enriched the ability of APOE to discern AD with stronger associations than to VD, MD, or all-cause dementia in a prospective community-based cohort.

Association of norepinephrine transporter methylation with in vivo NET expression and hyperactivity-impulsivity symptoms in ADHD measured with PET.

Attention deficit hyperactivity disorder (ADHD) is a common neurodevelopmental disorder with a robust genetic influence. The norepinephrine transporter (NET) is of particular interest as it is one of the main targets in treatment of the disorder. As ADHD is a complex and polygenetic condition, the possible regulation by epigenetic processes has received increased attention. We sought to determine possible differences in NET promoter DNA methylation between patients with ADHD and healthy controls. DNA methylation levels in the promoter region of the NET were determined in 23 adult patients with ADHD and 23 healthy controls. A subgroup of 18 patients with ADHD and 18 healthy controls underwent positron emission tomography (PET) with the radioligand (S,S)-[18F]FMeNER-D2 to quantify the NET in several brain areas in vivo. Analyses revealed significant differences in NET methylation levels at several cytosine-phosphate-guanine (CpG) sites between groups. A defined segment of the NET promoter ("region 1") was hypermethylated in patients in comparison with controls. In ADHD patients, a negative correlation between methylation of a CpG site in this region and NET distribution in the thalamus, locus coeruleus, and the raphe nuclei was detected. Furthermore, methylation of several sites in region 1 was negatively associated with the severity of hyperactivity-impulsivity symptoms. Our results point to an epigenetic dysregulation in ADHD, possibly due to a compensatory mechanisms or additional factors involved in transcriptional processing.

Genome-wide common and rare variant analysis provides novel insights into clozapine-associated neutropenia.

This corrects the article DOI: 10.1038/mp.2016.97.

Clinical factors predicting treatment resistant depression: affirmative results from the European multicenter study.

OBJECTIVES: Clinical variables were investigated in the 'treatment resistant depression (TRD)- III' sample to replicate earlier findings by the European research consortium 'Group for the Study of Resistant Depression' (GSRD) and enable cross-sample prediction of treatment outcome in TRD. EXPERIMENTAL PROCEDURES: TRD was defined by a Montgomery and Åsberg Depression Rating Scale (MADRS) score ≥22 after at least two antidepressive trials. Response was defined by a decline in MADRS score by ≥50% and below a threshold of 22. Logistic regression was applied to replicate predictors for TRD among 16 clinical variables in 916 patients. Elastic net regression was applied for prediction of treatment outcome. RESULTS: Symptom severity (odds ratio (OR) = 3.31), psychotic symptoms (OR = 2.52), suicidal risk (OR = 1.74), generalized anxiety disorder (OR = 1.68), inpatient status (OR = 1.65), higher number of antidepressants administered previously (OR = 1.23), and lifetime depressive episodes (OR = 1.15) as well as longer duration of the current episode (OR = 1.022) increased the risk of TRD. Prediction of TRD reached an accuracy of 0.86 in the independent validation set, TRD-I. CONCLUSION: Symptom severity, suicidal risk, higher number of lifetime depressive episodes, and comorbid anxiety disorder were replicated as the most prominent risk factors for TRD. Significant predictors in TRD-III enabled robust prediction of treatment outcome in TRD-I.

Associations between psychosis endophenotypes across brain functional, structural, and cognitive domains.

BACKGROUND: A range of endophenotypes characterise psychosis, however there has been limited work understanding if and how they are inter-related. METHODS: This multi-centre study includes 8754 participants: 2212 people with a psychotic disorder, 1487 unaffected relatives of probands, and 5055 healthy controls. We investigated cognition [digit span (N = 3127), block design (N = 5491), and the Rey Auditory Verbal Learning Test (N = 3543)], electrophysiology [P300 amplitude and latency (N = 1102)], and neuroanatomy [lateral ventricular volume (N = 1721)]. We used linear regression to assess the interrelationships between endophenotypes. RESULTS: The P300 amplitude and latency were not associated (regression coef. -0.06, 95% CI -0.12 to 0.01, p = 0.060), and P300 amplitude was positively associated with block design (coef. 0.19, 95% CI 0.10-0.28, p 0.38). All the cognitive endophenotypes were associated with each other in the expected directions (all p < 0.001). Lastly, the relationships between pairs of endophenotypes were consistent in all three participant groups, differing for some of the cognitive pairings only in the strengths of the relationships. CONCLUSIONS: The P300 amplitude and latency are independent endophenotypes; the former indexing spatial visualisation and working memory, and the latter is hypothesised to index basic processing speed. Individuals with psychotic illnesses, their unaffected relatives, and healthy controls all show similar patterns of associations between endophenotypes, endorsing the theory of a continuum of psychosis liability across the population.

Genome-wide common and rare variant analysis provides novel insights into clozapine-associated neutropenia.

The antipsychotic clozapine is uniquely effective in the management of schizophrenia; however, its use is limited by its potential to induce agranulocytosis. The causes of this, and of its precursor neutropenia, are largely unknown, although genetic factors have an important role. We sought risk alleles for clozapine-associated neutropenia in a sample of 66 cases and 5583 clozapine-treated controls, through a genome-wide association study (GWAS), imputed human leukocyte antigen (HLA) alleles, exome array and copy-number variation (CNV) analyses. We then combined associated variants in a meta-analysis with data from the Clozapine-Induced Agranulocytosis Consortium (up to 163 cases and 7970 controls). In the largest combined sample to date, we identified a novel association with rs149104283 (odds ratio (OR)=4.32, P=1.79 × 10-8), intronic to transcripts of SLCO1B3 and SLCO1B7, members of a family of hepatic transporter genes previously implicated in adverse drug reactions including simvastatin-induced myopathy and docetaxel-induced neutropenia. Exome array analysis identified gene-wide associations of uncommon non-synonymous variants within UBAP2 and STARD9. We additionally provide independent replication of a previously identified variant in HLA-DQB1 (OR=15.6, P=0.015, positive predictive value=35.1%). These results implicate biological pathways through which clozapine may act to cause this serious adverse effect.

Genome-wide common and rare variant analysis provides novel insights into clozapine-associated neutropenia.

This corrects the article DOI: 10.1038/mp.2016.97.

[Pharmacogenetics in psychiatry: state of the art]. / Pharmakogenetik in der Psychiatrie: eine Standortbestimmung.

In this article, the current literature on pharmacogenetics of antidepressants, antipsychotics and lithium are summarized by the section of Neurobiology and Genetics of the German Society of Psychiatry, Psychotherapy and Neurology (DGPPN). The publications of international expert groups and regulatory authorities are reviewed and discussed. In Germany, a statement on pharmacogenetics was also made by the gene diagnostics committee of the Ministry of Health. The DGPPN supports two recommendations: 1) to perform CYP2D6 genetic testing prior to prescription of tricyclic antidepressants and 2) to determine the HLA-B*1502 genotype in patients of Asian origin before using carbamazepine. The main obstacle for a broad application of pharmacogenetic tests in psychiatry remains the lack of large prospective studies, for both single gene-drug pair and cobinatorial pharmacogenetic tests, to evaluate the benefits of genetic testing. Psychiatrists, geneticists and funding agencies are encouraged to increase their efforts for the future benefit of psychiatric patients.

High loading of polygenic risk in cases with chronic schizophrenia.

Genomic risk profile scores (GRPSs) have been shown to predict case-control status of schizophrenia (SCZ), albeit with varying sensitivity and specificity. The extent to which this variability in prediction accuracy is related to differences in sampling strategies is unknown. Danish population-based registers and Neonatal Biobanks were used to identify two independent incident data sets (denoted target and replication) comprising together 1861 cases with SCZ and 1706 controls. A third data set was a German prevalent sample with diagnoses assigned to 1773 SCZ cases and 2161 controls based on clinical interviews. GRPSs were calculated based on the genome-wide association results from the largest SCZ meta-analysis yet conducted. As measures of genetic risk prediction, Nagelkerke pseudo-R(2) and variance explained on the liability scale were calculated. GRPS for SCZ showed positive correlations with the number of psychiatric admissions across all P-value thresholds in both the incident and prevalent samples. In permutation-based test, Nagelkerke pseudo-R(2) values derived from samples enriched for frequently admitted cases were found to be significantly higher than for the full data sets (Ptarget=0.017, Preplication=0.04). Oversampling of frequently admitted cases further resulted in a higher proportion of variance explained on the liability scale (improvementtarget= 50%; improvementreplication= 162%). GRPSs are significantly correlated with chronicity of SCZ. Oversampling of cases with a high number of admissions significantly increased the amount of variance in liability explained by GRPS. This suggests that at least part of the effect of common single-nucleotide polymorphisms is on the deteriorative course of illness.

Genome-wide autozygosity is associated with lower general cognitive ability.

Inbreeding depression refers to lower fitness among offspring of genetic relatives. This reduced fitness is caused by the inheritance of two identical chromosomal segments (autozygosity) across the genome, which may expose the effects of (partially) recessive deleterious mutations. Even among outbred populations, autozygosity can occur to varying degrees due to cryptic relatedness between parents. Using dense genome-wide single-nucleotide polymorphism (SNP) data, we examined the degree to which autozygosity associated with measured cognitive ability in an unselected sample of 4854 participants of European ancestry. We used runs of homozygosity-multiple homozygous SNPs in a row-to estimate autozygous tracts across the genome. We found that increased levels of autozygosity predicted lower general cognitive ability, and estimate a drop of 0.6 s.d. among the offspring of first cousins (P=0.003-0.02 depending on the model). This effect came predominantly from long and rare autozygous tracts, which theory predicts as more likely to be deleterious than short and common tracts. Association mapping of autozygous tracts did not reveal any specific regions that were predictive beyond chance after correcting for multiple testing genome wide. The observed effect size is consistent with studies of cognitive decline among offspring of known consanguineous relationships. These findings suggest a role for multiple recessive or partially recessive alleles in general cognitive ability, and that alleles decreasing general cognitive ability have been selected against over evolutionary time.

[Search for risk genes in schizophrenia]. / Suche nach Risikogenen bei Schizophrenie.

BACKGROUND: Schizophrenia is a severe psychiatric disease affecting approximately 0.5-1% of the general population. The relative contribution of genetic factors has been estimated to be 64-81%. OBJECTIVE: This review summarizes recent efforts to identify genetic variants associated with schizophrenia. METHODS: Relevant linkage and candidate genes as well as genome wide association studies, studies on copy number variants and next generation sequencing are presented and discussed. RESULTS: The latest and worldwide largest study on the genetics of schizophrenia found 128 genome wide significant single nucleotide polymorphisms (SNP) and 108 genome wide loci. The most obvious association is with genetic variations in the major histocompatibility complex (MHC). Besides polymorphisms, structural variants in the form of copy number variants (CNV), such as microdeletions and microduplications have a very high impact in a subgroup of patients. These CNVs are mainly microdeletions on 1q21.1, 2p16.3, 3q29, 15q13.3 and 16p11.2 as well as a large deletion on 22q11.21 and a microduplication on 16p11.2. CONCLUSION: A large new body of evidence on the genetics of schizophrenia is expected through next generation sequencing approaches. Future studies will particularly address the functional characterization of genetic variants.

[Guideline-conform psychiatric psychotherapeutic treatment for patients with schizophrenia : A normative evaluation of necessary personnel requirements]. / Leitlinienkonforme psychiatrisch-psychotherapeutische Behandlung für Patienten mit Schizophrenie : Eine normative Berechnung des benötigten Personalbedarfs.

BACKGROUND: Although national treatment guidelines and current publications of the German Federal Joint Committee (Gemeinsamer Bundesausschuss) recommend cognitive behavior therapy for all patients with schizophrenia, the implementation of these recommendations in current inpatient and outpatient treatment is only rudimentary. OBJECTIVES: The aim of this study was to systematically search randomized controlled studies (RCTs), meta-analyses and the guidelines of the German Association for Psychiatry and Psychotherapy, Psychosomatics and Neurology (DGPPN) and the British National Institute for Health and Clinical Excellence (NICE) in order to assess the number of personnel necessary for psychiatric and therapeutic inpatient treatment in line with present guidelines. Moreover, the number of staff required was compared with the personnel resources designated by the German psychiatry personnel regulations (Psych-PV). METHODS: The German and NICE guidelines, RCTs and meta-analyses were analyzed and an adequate weekly treatment plan for an inpatient unit was developed. Moreover, the number of personnel necessary to realize the treatment plan was calculated. RESULTS: In order to realize adequate inpatient treatment approximately 107 min extra for medical psychotherapeutic personnel per patient and week (of which 72 min for psychotherapy) and another 60 min for nursing staff per patient and week are required in addition to the current Psych-PV regulations. Thus, implementation in an open ward with 20 inpatients would require 3.62 positions for physicians, 0.7 positions in psychology and 12.85 positions for nursing staff (including management positions and night shifts). DISCUSSION: These evidence-based recommendations for precise specifications of inpatient treatment should lead to improved inpatient treatment in line with present guidelines. Moreover, outpatients and day patients could be included in this treatment model. The results should be considered in the construction of the future prospective payment system for inpatient psychiatric healthcare in Germany.

Genome-wide association study of alcohol dependence:significant findings in African- and European-Americans including novel risk loci.

We report a GWAS of alcohol dependence (AD) in European-American (EA) and African-American (AA) populations, with replication in independent samples of EAs, AAs and Germans. Our sample for discovery and replication was 16 087 subjects, the largest sample for AD GWAS to date. Numerous genome-wide significant (GWS) associations were identified, many novel. Most associations were population specific, but in several cases were GWS in EAs and AAs for different SNPs at the same locus,showing biological convergence across populations. We confirmed well-known risk loci mapped to alcohol-metabolizing enzyme genes, notably ADH1B (EAs: Arg48His, P=1.17 × 10(-31); AAs: Arg369Cys, P=6.33 × 10(-17)) and ADH1C in AAs (Thr151Thr, P=4.94 × 10(-10)), and identified novel risk loci mapping to the ADH gene cluster on chromosome 4 and extending centromerically beyond it to include GWS associations at LOC100507053 in AAs (P=2.63 × 10(-11)), PDLIM5 in EAs (P=2.01 × 10(-8)), and METAP in AAs (P=3.35 × 10(-8)). We also identified a novel GWS association (1.17 × 10(-10)) mapped to chromosome 2 at rs1437396, between MTIF2 and CCDC88A, across all of the EA and AA cohorts, with supportive gene expression evidence, and population-specific GWS for markers on chromosomes 5, 9 and 19. Several of the novel associations implicate direct involvement of, or interaction with, genes previously identified as schizophrenia risk loci. Confirmation of known AD risk loci supports the overall validity of the study; the novel loci are worthy of genetic and biological follow-up. The findings support a convergence of risk genes (but not necessarily risk alleles) between populations, and, to a lesser extent, between psychiatric traits.

Molecular genetic evidence for overlap between general cognitive ability and risk for schizophrenia: a report from the Cognitive Genomics consorTium (COGENT).

It has long been recognized that generalized deficits in cognitive ability represent a core component of schizophrenia (SCZ), evident before full illness onset and independent of medication. The possibility of genetic overlap between risk for SCZ and cognitive phenotypes has been suggested by the presence of cognitive deficits in first-degree relatives of patients with SCZ; however, until recently, molecular genetic approaches to test this overlap have been lacking. Within the last few years, large-scale genome-wide association studies (GWAS) of SCZ have demonstrated that a substantial proportion of the heritability of the disorder is explained by a polygenic component consisting of many common single-nucleotide polymorphisms (SNPs) of extremely small effect. Similar results have been reported in GWAS of general cognitive ability. The primary aim of the present study is to provide the first molecular genetic test of the classic endophenotype hypothesis, which states that alleles associated with reduced cognitive ability should also serve to increase risk for SCZ. We tested the endophenotype hypothesis by applying polygenic SNP scores derived from a large-scale cognitive GWAS meta-analysis (~5000 individuals from nine nonclinical cohorts comprising the Cognitive Genomics consorTium (COGENT)) to four SCZ case-control cohorts. As predicted, cases had significantly lower cognitive polygenic scores compared to controls. In parallel, polygenic risk scores for SCZ were associated with lower general cognitive ability. In addition, using our large cognitive meta-analytic data set, we identified nominally significant cognitive associations for several SNPs that have previously been robustly associated with SCZ susceptibility. Results provide molecular confirmation of the genetic overlap between SCZ and general cognitive ability, and may provide additional insight into pathophysiology of the disorder.

Analysis of genetic diversity in patients with major psychiatric disorders versus healthy controls: A molecular-genetic study of 1698 subjects genotyped for 100 candidate genes (549 SNPs).

BACKGROUND: This study analyzed the extent to which irregularities in genetic diversity separate psychiatric patients from healthy controls. METHODS: Genetic diversity was quantified through multidimensional "gene vectors" assembled from 4 to 8 polymorphic SNPs located within each of 100 candidate genes. The number of different genotypic patterns observed per gene was called the gene's "diversity index". RESULTS: The diversity indices were found to be only weakly correlated with their constituent number of SNPs (20.5 % explained variance), thus suggesting that genetic diversity is an intrinsic gene property that has evolved over the course of evolution. Significant deviations from "normal" diversity values were found for (1) major depression; (2) Alzheimer's disease; and (3) schizoaffective disorders. Almost one third of the genes were correlated with each other, with correlations ranging from 0.0303 to 0.7245. The central finding of this study was the discovery of "singular genes" characterized by distinctive genotypic patterns that appeared exclusively in patients but not in healthy controls. Neural Nets yielded nonlinear classifiers that correctly identified up to 90 % of patients. Overlaps between diagnostic subgroups on the genotype level suggested that (1) diagnoses-crossing vulnerabilities are likely involved in the pathogenesis of major psychiatric disorders; (2) clinically defined diagnoses may not constitute etiological entities. CONCLUSION: Detailed analyses of the variation of genotypic patterns in genes along with the correlation between genes lead to nonlinear classifiers that enable very robust separation between psychiatric patients and healthy controls on the genotype level.

Morphological correlates of anxiety-related experiences during a ketamine infusion.

OBJECTIVES: Ketamine exerts rapid antidepressant effects by enhancing neuroplasticity, particularly in the amygdala and hippocampus-regions involved in fear processing and learning. While the role of ketamine's dissociative effects in its antidepressant response is debated, anxiety experienced during infusion has been negatively correlated with treatment outcomes. METHODS: In this single-blind, placebo-controlled study, a subset of 17 healthy volunteers (6 males, 23.12 ± 1.9 years) received intravenously a placebo in the first and 0.5 mg/kg racemic ketamine in the second session. Anxiety-related experiences were assessed by the 5D-ASC score obtained post-infusion, structural magnetic resonance imaging scans were acquired 4 h post-infusion. An anxiety-score was obtained from the 5D-ASC. Relation between post-placebo amygdala volume, hippocampal volume, and its subfields with the anxiety-score were assessed using linear regression models. RESULTS: Results showed a statistically significant negative relation between hippocampal head volume and the anxiety score (ß = -0.733, p = 0.006), with trending negative association for each subfield's head and the score. CONCLUSION: These findings suggest that anxiety-related experiences during ketamine infusion may be mediated by the hippocampus, with smaller hippocampal volumes leading to more anxiety-related experiences. Thus, hippocampal subfield volumes may be used as a predictor for anxiety-related events during ketamine use and might predict treatment outcome in future approaches.