Etiologie en psychiatrie: embrasser la réalité de la causalité poly-génétique-environnementale de la maladie mentale

Aperçu: G.M.

Les résultats intrigants sur la causalité génétique et environnementale suggèrent un besoin de recadrer l'étiologie des troubles mentaux.

La génétique moléculaire montre que des milliers de variantes génétiques communes et rares contribuent à la maladie mentale. Des études épidémiologiques ont identifié des dizaines d'expositions environnementales associées à la psychopathologie. 

Les analyses intégratives de la co-causalité, y compris l'interaction génique-environnement et les interactions environnement-environnement, permettent de découvrir des types et mécanismes de causalité susceptibles de générer de nouveaux outils préventifs et thérapeutiques. 

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World Psychiatry. 2017 Jun;16(2):121-129. doi: 10.1002/wps.20436.

Etiology in psychiatry: embracing the reality of poly-gene-environmental causation of mental illness

Uher R¹, Zwicker A¹.

Author information

1

Departments of Psychiatry and Pathology, Dalhousie University, Halifax, B3H 2E2, Nova Scotia, Canada.

Abstract

Intriguing findings on genetic and environmental causation suggest a need to reframe the etiology of mental disorders. Molecular genetics shows that thousands of common and rare genetic variants contribute to mental illness. Epidemiological studies have identified dozens of environmental exposures that are associated with psychopathology. The effect of environment is likely conditional on genetic factors, resulting in gene-environment interactions. The impact of environmental factors also depends on previous exposures, resulting in environment-environment interactions. Most known genetic and environmental factors are shared across multiple mental disorders. Schizophrenia, bipolar disorder and major depressive disorder, in particular, are closely causally linked. Synthesis of findings from twin studies, molecular genetics and epidemiological research suggests that joint consideration of multiple genetic and environmental factors has much greater explanatory power than separate studies of genetic or environmental causation. Multi-factorial gene-environment interactions are likely to be a generic mechanism involved in the majority of cases of mental illness, which is only partially tapped by existing gene-environment studies. Future research may cut across psychiatric disorders and address poly-causation by considering multiple genetic and environmental measures across the life course with a specific focus on the first two decades of life. Integrative analyses of poly-causation including gene-environment and environment-environment interactions can realize the potential for discovering causal types and mechanisms that are likely to generate new preventive and therapeutic tools.

© 2017 World Psychiatric Association.

PMID:28498595

PMCID:PMC5428165   [Available on 2017-06-01]

DOI:10.1002/wps.20436