[The value of re-evaluation and thorough family history taking for the diagnostic work-up of chorea]. / Het diagnostisch proces bij chorea: het belang van heroverwegen en de familieanamnese.

The differential diagnosis of chorea encompasses a broad range of disorders. In psychiatry, tardive dyskinesia may be difficult to discern from other causes, particularly when the family history is negative. A 59-year-old man with an unclear medical history had been using risperidone for over a decade when we first saw him. He presented with severe dyskinesia in all extremities. The family history for neuropsychiatric disorders was negative. We interpreted the movement disorder as tardive dyskinesia, but later he turned out to suffer from Huntington’s disease. To improve diagnostic accuracy, we should have more frequently re-evaluated the differential diagnosis and our family history should have been more thorough. We outline the diagnostic considerations in patients presenting with chorea. Finally, we highlight the value of diagnostic re-evaluation and thorough family history taking to optimize diagnostic accuracy in neuropsychiatry.

[Sustainability in Flemish and Dutch mental health care]. / Duurzaamheid in de Vlaamse en Nederlandse ggz.

BACKGROUND: The Flemish and Dutch (mental) health sectors cause greenhouse gas emissions and therefore will have to make an effort to reduce their climate impact. AIM: To assess whether differences can be found in the climate policies of Flemish and Dutch mental health institutions. METHOD: Descriptive research based on a sustainability questionnaire, in which concrete actions, objectives and ambitions in the field of sustainability were questioned at Flemish and Dutch mental health institutions. RESULTS: 59% and 38% of respectively the Flemish and Dutch institutions fully agreed that sustainability is a very important theme (with a main focus on sustainable energy transition and recycling in both regions). Statistically significant differences between both regions were only found with regard to fostering more sustainable commuting (stronger in Flanders; p < 0.0001). The climate impact of medicines and food, as well as investments in sustainable projects, received little attention. CONCLUSION: Although a substantial part of Flemish and Dutch mental health institutions consider sustainability (very) important, a systemic ‘transformation’ will be necessary to make them climate neutral.

[Towards personalized treatment with clozapine]. / Op naar een gepersonaliseerde clozapinebehandeling.

BACKGROUND: Clozapine is the most effective treatment for people with treatment-resistant schizophrenia. However, it is prescribed less often than guidelines indicate. AIM: To personalize clozapine treatment, we investigated the efficacy of clozapine as first- or second-line treatment and investigated whether there are factors that were associated with efficacy and side effects. METHOD: We collected a unique cohort of over 800 clozapine users diagnosed with a schizophrenia spectrum disorder. We meta-analyzed factors that were associated with response during clozapine treatment. Additionally, we conducted genetic association analyses to investigate the relations between side effects and symptom severity during clozapinetreatment. RESULTS: From our meta-analyses, we found that clozapine was more effective when used as a first- or second-line treatment. Furthermore, we found that younger age, less negative symptoms and the paranoid subtype of schizophreniawere associated with a better clozapine response. Several specific locations on genes (loci) were associated with clozapine-induced agranulocytosis and neutropenia, while polygenic risk scores were associated with symptom severity. CONCLUSION: We found that clozapine could be effective earlier in treatment and identified factors that could aid the prediction of< response to clozapine treatment in the future. These finding could contribute to the start of a personalized clozapine treatment.

Longitudinal associations between alcohol use, smoking, genetic risk scoring and symptoms of depression in the general population: a prospective 6-year cohort study.

BACKGROUND: Alcohol consumption, smoking and mood disorders are leading contributors to the global burden of disease and are highly comorbid. Yet, their interrelationships have remained elusive. The aim of this study was to examine the multi-cross-sectional and longitudinal associations between (change in) smoking and alcohol use and (change in) number of depressive symptoms. METHODS: In this prospective, longitudinal study, 6646 adults from the general population were included with follow-up measurements after 3 and 6 years. Linear mixed-effects models were used to test multi-cross-sectional and longitudinal associations, with smoking behaviour, alcohol use and genetic risk scores for smoking and alcohol use as independent variables and depressive symptoms as dependent variables. RESULTS: In the multi-cross-sectional analysis, smoking status and number of cigarettes per day were positively associated with depressive symptoms (p < 0.001). Moderate drinking was associated with less symptoms of depression compared to non-use (p = 0.011). Longitudinally, decreases in the numbers of cigarettes per day and alcoholic drinks per week as well as alcohol cessation were associated with a reduction of depressive symptoms (p = 0.001-0.028). Results of genetic risk score analyses aligned with these findings. CONCLUSIONS: While cross-sectionally smoking and moderate alcohol use show opposing associations with depressive symptoms, decreases in smoking behaviour as well as alcohol consumption are associated with improvements in depressive symptoms over time. Although we cannot infer causality, these results open avenues to further investigate interventions targeting smoking and alcohol behaviours in people suffering from depressive symptoms.

[Relating the history of genetics to the field of psychiatric genetics: the discovery, reading and writing of DNA]. / De geschiedenis van de (psychiatrische) genetica: ontdekken, lezen en schrijven van DNA.

BACKGROUND: The importance of genetics in psychiatry has been a topic of ongoing debate. The futile search for candidate genes underlying psychiatric disorders in the decades before 2007 resulted in overall disappointment. Since then, however, researchers and clinicians have witnessed the discovery of a plethora of common and rare genetic variants associated with psychiatric disorders.
AIM: To relate the history of general genetics to the history of psychiatric genetics, underlining how.
METHOD: Literature research.
RESULTS: The anatomical and physiological phases of this history have shaped the field of psychiatric genetics. We describe pivotal discoveries that have facilitated the uncovering, reading and writing of DNA. We then discuss several milestone discoveries in the field of psychiatric genetics. We end with an outlook on where the field of psychiatric genetics may be heading in the decades to come, arguing that a ‘clinical phase’ of psychiatric genetics may be ahead of us.
CONCLUSION: The research with a focus on polygenic risk scores (PRS) could be translated into clinical practice in the coming years and we expect more attention to the question of how genetic variants cause psychiatric disorders. We look to future developments with some optimism.
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[Genetic risk of mental illness: what do we know and how do we communicate this?] / Genetisch risico van psychiatrische ziekten: wat weten we en hoe communiceren we dat?

BACKGROUND: Insights from psychiatric genetics research and large international psychiatric genetics consortia are promising but still remain outside the realm of clinical practice.
AIM: To provide an overview of developments in the field of psychiatric genetics; and to offer guidance for health professionals how to assess and manage clinical implications of these developments.
METHOD: In this review, we address: recent developments in psychiatric genetics, with a focus on polygenic risk scores (PRS); ethical dilemmas associated with clinical application of PRS; and basic principles of genetic counseling for psychiatric disorders.
RESULTS: PRS are not yet ready for implementation in clinical practice because of limited predictive value and poor generalizability. In addition, it is still unclear how genetic risk and PRS can be communicated clearly to patients and families.
CONCLUSION: Advances in psychiatric genetics and increased availability of genetic risk scores may lead to questions from patients and families coping with psychiatric illness. These questions may be best addressed using psychiatric genetic counseling techniques. We recommend that psychiatrists have some basic knowledge of psychiatric genetics and know how to refer their patients to a clinical geneticist. Implementing a psychiatric genetics theme in training and education may be helpful.
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[Guidelines on genetic testing in psychiatry: an overview]. / Leidraad genetisch testen in de psychiatrie.

BACKGROUND: In recent years, technological advances have led to the identification of numerous genetic variations that are associated with psychiatric symptoms. Establishing a genetic cause may provide patients and family members with an explanation for the problems and in specific cases allows targeted treatment of psychiatric and somatic (co)morbidity. At present, patients with psychiatric disorders are rarely referred for genetic testing. AIM: To provide an overview of literature and (inter)national guidelines in the field of genetic testing for patients with psychiatric disorder, and to present guidance on indications for genetic testing in clinical practice. METHOD: A systematic search was conducted in PubMed and Embase focusing on articles with recommendations on genetic testing in psychiatric disorders. In addition, national and international guidelines on genetic testing in psychiatry were studied. The main findings were summarized in an infographic. RESULTS: Based on the current literature and (inter)national guidelines, patients with (comorbid) intellectual disability should always be referred to a clinical geneticist. Psychiatrists should consider genetic testing in patients with other psychiatric disorders if there are ‘red flags’ such as a positive family history, congenital abnormalities, developmental delay, dysmorphic features, movement disorders or cognitive decline. Psychiatrists may request genetic testing themselves or refer patients to clinical geneticists. CONCLUSION: Psychiatric disorders may be underpinned by a genetic anomaly, particularly in patients presenting with psychiatric as well as somatic symptomatology. Psychiatrists should recognize symptoms and warning signs indicative of an underlying genetic abnormality, and know when to refer their patients for genetic testing.

[Interplay between genetic background and environmental factors in psychiatry: current situation and future prospects]. / Samenspel tussen genetische achtergrond en omgevingsfactoren in de psychiatrie: stand van zaken en toekomstperspectief.

BACKGROUND: The hypothesis that etiopathogeneses of psychiatric disorders are determined by interplay between genetic background and environmental factors, as well their interactions can increasingly be put to direct scientific test, based on a wave of methodological, technological and knowledge developments.
AIM: To provide insight into and to provide perspective on some important scientific developments and facilitate challenges in this area.
METHOD: Narrative overview of the scientific literature and formulation of a concept and future perspective.
RESULTS: The overview points to concrete progress in the fields of genetic epidemiology, environmental analyses, gene-environment interactions and epigenetics in psychiatry. For example, recent studies have provided evidence for the existence of interactions and correlations between genetic and environmental factors, interdependence of risk-influencing effects of environmental factors, and translational neurobiological studies have identified biological processes that influence the impact of (or the response to) environmental influences on individuals mediate. These important steps to translate epidemiological research into testable biological hypotheses are facilitated by new techniques and the availability of large and relevant clinical and biological datasets.
CONCLUSION: Scientific progress on the interplay between genetic background and environmental factors enriches the conceptual framework of the etiopathogenesis of mental disorders and provides a future perspective in which we are likely to receive answers to a number of clinically relevant questions in the coming decade.
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Genome-wide association analyses of symptom severity among clozapine-treated patients with schizophrenia spectrum disorders.

Clozapine is the most effective antipsychotic for patients with treatment-resistant schizophrenia. However, response is highly variable and possible genetic underpinnings of this variability remain unknown. Here, we performed polygenic risk score (PRS) analyses to estimate the amount of variance in symptom severity among clozapine-treated patients explained by PRSs (R2) and examined the association between symptom severity and genotype-predicted CYP1A2, CYP2D6, and CYP2C19 enzyme activity. Genome-wide association (GWA) analyses were performed to explore loci associated with symptom severity. A multicenter cohort of 804 patients (after quality control N = 684) with schizophrenia spectrum disorder treated with clozapine were cross-sectionally assessed using the Positive and Negative Syndrome Scale and/or the Clinical Global Impression-Severity (CGI-S) scale. GWA and PRS regression analyses were conducted. Genotype-predicted CYP1A2, CYP2D6, and CYP2C19 enzyme activities were calculated. Schizophrenia-PRS was most significantly and positively associated with low symptom severity (p = 1.03 × 10-3; R2 = 1.85). Cross-disorder-PRS was also positively associated with lower CGI-S score (p = 0.01; R2 = 0.81). Compared to the lowest tertile, patients in the highest schizophrenia-PRS tertile had 1.94 times (p = 6.84×10-4) increased probability of low symptom severity. Higher genotype-predicted CYP2C19 enzyme activity was independently associated with lower symptom severity (p = 8.44×10-3). While no locus surpassed the genome-wide significance threshold, rs1923778 within NFIB showed a suggestive association (p = 3.78×10-7) with symptom severity. We show that high schizophrenia-PRS and genotype-predicted CYP2C19 enzyme activity are independently associated with lower symptom severity among individuals treated with clozapine. Our findings open avenues for future pharmacogenomic projects investigating the potential of PRS and genotype-predicted CYP-activity in schizophrenia.

Comprehensive analyses of RNA-seq and genome-wide data point to enrichment of neuronal cell type subsets in neuropsychiatric disorders.

Neurological and psychiatric disorders, including substance use disorders, share a range of symptoms, which could be the result of shared genetic background. Many genetic loci have been identified for these disorders using genome-wide association studies, but conclusive evidence about cell types wherein these loci are active is lacking. We aimed to uncover implicated brain cell types in neuropsychiatric traits and to assess consistency in results across RNA datasets and methods. We therefore comprehensively employed cell type enrichment methods by integrating single-cell transcriptomic data from mouse brain regions with an unprecedented dataset of 42 human genome-wide association study results of neuropsychiatric, substance use and behavioral/quantitative brain-related traits (n = 12,544,007 individuals). Single-cell transcriptomic datasets from the Karolinska Institute and 10x Genomics were used. Cell type enrichment was determined using Linkage Disequilibrium Score Regression, Multi-marker Analysis of GenoMic Annotation, and Data-driven Expression Prioritized Integration for Complex Traits. We found the largest degree of consistency across methods for implication of pyramidal cells in schizophrenia and cognitive performance. For other phenotypes, such as bipolar disorder, two methods implicated the same cell types, i.e., medium spiny neurons and pyramidal cells. For autism spectrum disorders and anorexia nervosa, no consistency in implicated cell types was observed across methods. We found no evidence for astrocytes being consistently implicated in neuropsychiatric traits. In conclusion, we provide comprehensive evidence for a subset of neuronal cell types being consistently implicated in several, but not all psychiatric disorders, while non-neuronal cell types seem less implicated.

[Validation of the Dutch Glasgow Anti- psychotic Side-Effect Scale for Clozapine]. / Glasgow Antipsychotica Bijwerkingen Schaal voor Clozapine; validatie van de Nederlandstalige versie.

BACKGROUND: To monitor the unique side effect pattern of clozapine, the Glasgow Antipsychotic Side-effect Scale for Clozapine (GASS-C) was developed in English and validated. This questionnaire was previously translated to Dutch, and revised, but not yet validated. AIM: The current study concerns the validation of the second revision of the GASS-C-NL-R2 for the Dutch language. METHOD: Two Spearman correlation tests were conducted to compare GASS-C-NL-R2 with the Dutch version of the Liverpool University Neuroleptic Side-Effect Rating Scale (LUNSERS) at two time p´oints. There was one week between these two time points. The test-retest reliability was determined using a Spearman correlation test and Cronbach's alpha on the GASS-C-NL-R2 between the two time points. In addition, a factor analysis was performed. RESULTS: Spearman's correlation coefficient between the GASS-C-NL-R2 and the LUNSERS was 0.830 (p < 0.001, n = 72) at the first time point and 0.684 (p < 0.001, n = 50) at the second time point. GASS-C-NL-R2 also had a strong test-retest reliability: Spearman's correlation coefficient was 0.680 (p < 0.001; n = 46), and Cronbach's alpha was 0.847, n = 78. Factor analysis showed that all questions were relevant. CONCLUSION: The current study shows that GASS-C-NL-R2 is a valid and reliable questionnaire to monitor side effects related to clozapine with a relatively high prevalence. Future studies should focus on the practical utility of GASS-C-NL-R2 with a larger sample size.

The genetic basis of major depression.

Major depressive disorder (MDD) is a common, debilitating, phenotypically heterogeneous disorder with heritability ranges from 30% to 50%. Compared to other psychiatric disorders, its high prevalence, moderate heritability, and strong polygenicity have posed major challenges for gene-mapping in MDD. Studies of common genetic variation in MDD, driven by large international collaborations such as the Psychiatric Genomics Consortium, have confirmed the highly polygenic nature of the disorder and implicated over 100 genetic risk loci to date. Rare copy number variants associated with MDD risk were also recently identified. The goal of this review is to present a broad picture of our current understanding of the epidemiology, genetic epidemiology, molecular genetics, and gene-environment interplay in MDD. Insights into the impact of genetic factors on the aetiology of this complex disorder hold great promise for improving clinical care.

Polygenic risk scores for genetic counseling in psychiatry: Lessons learned from other fields of medicine.

Polygenic risk scores (PRS) may aid in the identification of individuals at-risk for psychiatric disorders, treatment optimization, and increase in prognostic accuracy. PRS may also add significant value to genetic counseling. Thus far, integration of PRSs in genetic counseling sessions remains problematic because of uncertainties in risk prediction and other concerns. Here, we review the current utility of PRSs in the context of clinical psychiatry. By comprehensively appraising the literature in other fields of medicine including breast cancer, Alzheimer's Disease, and cardiovascular disease, we outline several lessons learned that could be applied to future studies and may thus benefit the incorporation of PRS in psychiatric genetic counseling. These include integrating PRS with environmental factors (e.g. lifestyle), setting up large-scale studies, and applying reproducible methods allowing for cross-validation between cohorts. We conclude that psychiatry may benefit from experiences in these fields. PRS may in future have a role in genetic counseling in clinical psychiatric practice, by advancing prevention strategies and treatment decision-making, thus promoting quality of life for (potentially) affected individuals.

Examining the independent and joint effects of genomic and exposomic liabilities for schizophrenia across the psychosis spectrum.

AIMS: Psychosis spectrum disorder has a complex pathoetiology characterised by interacting environmental and genetic vulnerabilities. The present study aims to investigate the role of gene-environment interaction using aggregate scores of genetic (polygenic risk score for schizophrenia (PRS-SCZ)) and environment liability for schizophrenia (exposome score for schizophrenia (ES-SCZ)) across the psychosis continuum. METHODS: The sample consisted of 1699 patients, 1753 unaffected siblings, and 1542 healthy comparison participants. The Structured Interview for Schizotypy-Revised (SIS-R) was administered to analyse scores of total, positive, and negative schizotypy in siblings and healthy comparison participants. The PRS-SCZ was trained using the Psychiatric Genomics Consortiums results and the ES-SCZ was calculated guided by the approach validated in a previous report in the current data set. Regression models were applied to test the independent and joint effects of PRS-SCZ and ES-SCZ (adjusted for age, sex, and ancestry using 10 principal components). RESULTS: Both genetic and environmental vulnerability were associated with case-control status. Furthermore, there was evidence for additive interaction between binary modes of PRS-SCZ and ES-SCZ (above 75% of the control distribution) increasing the odds for schizophrenia spectrum diagnosis (relative excess risk due to interaction = 6.79, [95% confidential interval (CI) 3.32, 10.26], p < 0.001). Sensitivity analyses using continuous PRS-SCZ and ES-SCZ confirmed gene-environment interaction (relative excess risk due to interaction = 1.80 [95% CI 1.01, 3.32], p = 0.004). In siblings and healthy comparison participants, PRS-SCZ and ES-SCZ were associated with all SIS-R dimensions and evidence was found for an interaction between PRS-SCZ and ES-SCZ on the total (B = 0.006 [95% CI 0.003, 0.009], p < 0.001), positive (B = 0.006 [95% CI, 0.002, 0.009], p = 0.002), and negative (B = 0.006, [95% CI 0.004, 0.009], p < 0.001) schizotypy dimensions. CONCLUSIONS: The interplay between exposome load and schizophrenia genetic liability contributing to psychosis across the spectrum of expression provide further empirical support to the notion of aetiological continuity underlying an extended psychosis phenotype.

Isolated nausea and vomiting as the cardinal presenting symptoms of clozapine-induced myocarditis: a case report.

BACKGROUND: Clozapine is an atypical antipsychotic proven to be superior in the treatment of treatment-resistant schizophrenia. Myocarditis is a rare, but well-known complication of treatment with clozapine. Only few cases have been reported in which nausea and vomiting were prominent symptoms. This is the first described report in which nausea and vomiting were the only presenting symptoms of clozapine-induced myocarditis. CASE PRESENTATION: We report a case of a 58-year-old woman, suffering from schizoaffective disorder, who is being treated with clozapine. Two weeks after initiation of clozapine, she developed nausea and vomiting, in absence of any other clinical symptoms. Laboratory examination and magnetic resonance imaging confirmed the diagnosis of clozapine-induced myocarditis. Clozapine was discontinued and the patient recovered fully. CONCLUSIONS: This case emphasizes the importance of recognizing myocarditis as a cause of isolated nausea and vomiting in patients treated with clozapine. Early recognition improves clinical outcome and reduces mortality.