The shock of the new: progress in schizophrenia genomics

Psychiatric Genomics and Mental Health Treatment: Setting the Ethical Agenda

Realizing the benefits of translating psychiatric genomics research into mental health care is not straightforward. The translation process gives rise to ethical challenges that are distinctive from challenges posed within psychiatric genomics research itself, or that form part of the delivery of clinical psychiatric genetics services. This article outlines and considers three distinct ethical concerns posed by the process of translating genomic research into frontline psychiatric practice and policy making. First, the genetic essentialism that is commonly associated with the genomics revolution in health care might inadvertently exacerbate stigma towards people with mental disorders. Secondly, the promises of genomic medicine advance a narrative of individual empowerment. This narrative could promote a fatalism towards patients' biology in ways that function in practice to undermine patients' agency and autonomy, or, alternatively, a heightened sense of subjective genetic responsibility could become embedded within mental health services that leads to psychosocial therapeutic approaches and the clinician-patient therapeutic alliance being undermined. Finally, adopting a genomics-focused approach to public mental health risks shifting attention away from the complex causal relationships between inequitable socio-economic, political, and cultural structures and negative mental health outcomes. The article concludes by outlining a number of potential pathways for future ethics research that emphasizes the importance of examining appropriate translation mechanisms, the complementarity between genetic and psychosocial models of mental disorder, the implications of genomic information for the clinician-patient relationship, and funding priorities and resource allocation decision making in mental health.

Application of fatty acid and lipid measurements in neuropsychiatry

The importance of lipids in the understanding of disease states is constantly increasing. Whilst the link between metabolic disorders and lipids seems to be clear, interpreting lipid regulation in the context of neuropsychiatric disorders is a new approach. Mental disorders account for almost 15% of the total global disease burden with Alzheimer’s disease, depression or schizophrenia being amongst the most widespread mental disorders in the general population. For this reason rapid and early diagnosis is crucial and finding the right biomarkers is of great importance. Lipids appear to be essential in learning the aetiopathology of neuropsychiatric diseases as well as in biomarker research as they are most abundantly present in the brain. This study discusses recent findings in neuropsychiatry in the context of lipid analysis.

Psychosis in adulthood is associated with high rates of ADHD and CD problems during childhood

BACKGROUND

Patients diagnosed with schizophrenia display poor premorbid adjustment (PPA) in half of the cases. Attention deficit/hyperactivity disorder (ADHD) and conduct disorder (CD) are common child psychiatric disorders. These two facts have not previously been linked in the literature.

AIMS

To determine the prevalence of ADHD/CD problems retrospectively among patients with psychoses, and whether and to what extent the high frequency of substance abuse problems among such patients may be linked to ADHD/CD problems.

METHOD

ADHD and CD problems/diagnoses were retrospectively recorded in one forensic (n = 149) and two non-forensic samples (n = 98 and n = 231) of patients with a psychotic illness: schizophrenia, bipolar or other, excluding drug-induced psychoses.

RESULTS

ADHD and CD were much more common among the patients than in the general population-the odds ratio was estimated to be greater than 5. There was no significant difference in this respect between forensic and non-forensic patients. Substance abuse was common, but substantially more common among patients with premorbid ADHD/CD problems.

CONCLUSIONS

Previous views regarding PPA among patients with a psychotic illness may reflect an association between childhood ADHD/CD and later psychosis. The nature of this association remains uncertain: two disorders sharing some generative mechanisms or one disorder with two main clinical manifestations. Childhood ADHD and particularly CD problems contribute to the high frequency of substance abuse in such groups.

Genome-wide association studies of suicidal behaviors: a review

Suicidal behaviors represent a fatal dimension of mental ill-health, involving both environmental and heritable (genetic) influences. The putative genetic components of suicidal behaviors have until recent years been mainly investigated by hypothesis-driven research (of "candidate genes"). But technological progress in genotyping has opened the possibilities towards (hypothesis-generating) genomic screens and novel opportunities to explore polygenetic perspectives, now spanning a wide array of possible analyses falling under the term Genome-Wide Association Study (GWAS). Here we introduce and discuss broadly some apparent limitations but also certain developing opportunities of GWAS. We summarize the results from all the eight GWAS conducted up to date focused on suicidality outcomes; treatment emergent suicidal ideation (3 studies), suicide attempts (4 studies) and completed suicides (1 study). Clearly, there are few (if any) genome-wide significant and reproducible findings yet to be demonstrated. We then discuss and pinpoint certain future considerations in relation to sample sizes, the units of genetic associations used, study designs and outcome definitions, psychiatric diagnoses or biological measures, as well as the use of genomic sequencing. We conclude that GWAS should have a lot more potential to show in the case of suicidal outcomes, than what has yet been realized.

Aetiology of schizophrenia and implications for nursing practice: a literature review

Schizophrenia is recognised as a major mental illness and is prevalent in approximately 1% of the global population. This paper reviewed literature published between 2001 and 2013 to explore the aetiology of schizophrenia and discuss implications for mental health nursing practice. Although the causes of schizophrenia are largely unknown, there is a strong correlation between identified physiological and environmental markers and the development of the disease. With this knowledge, mental health nurses can potentially contribute to the development of strategies and approaches to complement current treatments, and therefore ensure improved outcomes for mental health clients.

Genetic dissection of the psychotomimetic effects of cannabinoid exposure

Cannabis use is an established risk factor for the development of schizophrenia and related psychotic disorders. Factors that may mediate susceptibility to the psychosis-inducing effects of cannabis include the age at onset of first cannabis use, genetic predisposition, as well as interaction with other environmental risk variables. Clinical and preclinical genetic studies provide increasing evidence that, in particular, genes encoding proteins implicated in dopamine signalling are implicated in the cannabis-psychosis association. In the present review, we focus on both human and animal studies which have focused on identifying the neuronal basis of these interactions. We conclude that further studies are required to provide greater mechanistic insight into the long-term and neurodevelopmental effects of cannabis use, with implications for improved understanding of the cannabis-psychosis relationship.

Genetically modified mice related to schizophrenia and other psychoses: seeking phenotypic insights into the pathobiology and treatment of negative symptoms

Modelling negative symptoms in any animal model, particularly in mice mutant for genes related to schizophrenia, is complicated by the absence of the following key elements that might assist in developing validation criteria: clinical clarity surrounding this symptom constellation; any clear association between negative symptoms and pathological signature(s) in the brain; and therapeutic strategies with material clinical efficacy against these symptoms. In this review, the application of mutant mouse models to the study of negative symptoms is subjected to critical evaluation, focussing on the following challenges: (a) conceptual issues relating to negative symptoms and their evaluation in mutant models; (b) measurement of negative symptoms in mice, in terms of social behaviour, motivational deficits/avolition and anhedonia; (c) studies in mutants with disruption of genes either regulating aspects of neurotransmission implicated in schizophrenia or associated with risk for psychotic illness; (d) the disaggregation of behavioural phenotypes into underlying pathobiological processes, as a key to the development of new therapeutic strategies for negative symptoms. Advances in genetic and molecular technologies are facilitating these processes, such that more accurate models of putative schizophrenia-linked genetic abnormalities are becoming feasible. This progress in terms of mimicking the genetic contribution to distinct domains of psychopathology associated with psychotic illness must be matched by advances in conceptual/clinical relevance and sensitivity/specificity of phenotypic assessments at the level of behaviour.

Patch-clamp recordings and calcium imaging followed by single-cell PCR reveal the developmental profile of 13 genes in iPSC-derived human neurons

Molecular genetic studies are typically performed on homogenized biological samples, resulting in contamination from non-neuronal cells. To improve expression profiling of neurons we combined patch recordings with single-cell PCR. Two iPSC lines (healthy subject and 22q11.2 deletion) were differentiated into neurons. Patch electrode recordings were performed on 229 human cells from Day-13 to Day-88, followed by capture and single-cell PCR for 13 genes: ACTB, HPRT, vGLUT1, βTUBIII, COMT, DISC1, GAD1, PAX6, DTNBP1, ERBB4, FOXP1, FOXP2, and GIRK2. Neurons derived from both iPSC lines expressed βTUBIII, fired action potentials, and experienced spontaneous depolarizations (UP states) ~2 weeks before vGLUT1, GAD1 and GIRK2 appeared. Multisite calcium imaging revealed that these UP states were not synchronized among hESC-H9-derived neurons. The expression of FOXP1, FOXP2 and vGLUT1 was lost after 50 days in culture, in contrast to other continuously expressed genes. When gene expression was combined with electrophysiology, two subsets of genes were apparent; those irrelevant to spontaneous depolarizations (including vGLUT1, GIRK2, FOXP2 and DISC1) and those associated with spontaneous depolarizations (GAD1 and ERBB4). The results demonstrate that in the earliest stages of neuron development, it is useful to combine genetic analysis with physiological characterizations, on a cell-to-cell basis.

Combined deletion of two Condensin II system genes (NCAPG2 and MCPH1) in a case of severe microcephaly and mental deficiency

7qter deletion syndrome includes prenatal and/or postnatal growth retardation, microcephaly, psychomotor delay or mental retardation and a characteristic dysmorphism. If clinical features are well described, the molecular mechanisms underlying the 7qter deletion syndrome remain unknown. Those deletions usually arise de novo. Here, we describe a young boy with an abnormal phenotype consistent with a 7qter deletion syndrome. High resolution genomic analysis (Affymetrix Human Genome Wide SNP 6.0) revealed a 7q36.3 deletion encompassing NCAPG2, ESYT2, WDR60 and VIPR2, inherited from his asymptomatic father and paternal grandfather. In addition, the patient also harbored a MCPH1 deletion inherited from his healthy mother. Combined NCAPG2 and MCPH1 deletions were correlated with low mRNA levels and protein expression in the patient. MCPH1 and NCAPG2 proteins interaction is known to control chromosome structure and we thus propose that double heterozygosity for null mutations of those two genes of the Condensin II system contribute to mental deficiency with severe microcephaly phenotype.

ENCODE and a new landscape for psychiatric genetics

Despite rigorous research into the genetics of neuropsychiatric disorders, the mechanism by which polygenic risk leads to complex clinical phenotypes remains unclear. The Encyclopedia of DNA Elements (ENCODE) project gives us new insight into gene regulation, and gene-gene and gene-environment interaction. Better understanding of these key genomic mechanisms may provide the answers we have been searching for.

Genetic models of schizophrenia and related psychotic disorders: progress and pitfalls across the methodological "minefield"

The challenge of modelling a complex and multifaceted disorder such as schizophrenia is epitomised by the considerable degree of phenotypic variability described in patients and by the absence of specific and consistent neuropathological biomarkers. The pattern and severity of a range of clinical features, including florid psychotic symptoms such as hallucinations and delusions, negative symptoms and cognitive dysfunction, together with age at onset, course of illness and other indices, can vary greatly between individual patients. The undefined nature of the relationship between diagnosis and underlying aetiology has complicated research in the field of clinical and preclinical neuroscience, thereby making it difficult to generate or evaluate appropriate disease models of schizophrenia. In the present review, we explore those conceptual and practical issues that relate specifically to the genetic modelling of schizophrenia and related disorders in rodents. Practical issues that impact on the robustness of endophenotypic findings and their translational relevance are discussed with reference to evidence from selective genetic models of candidate risk genes and copy number variants implicated in schizophrenia.