Gandal, Haney, J. R., Parikshak, N. N., Leppa, V., Ramaswami, G., Hartl, C., Schork, A. J., Appadurai, V., Buil, A., Werge, T. M., Liu, C., White, K. P., Horvath, S., & Geschwind, D. H. (2018). Shared molecular neuropathology across major psychiatric disorders parallels polygenic overlap. Science (American Association for the Advancement of Science), 359(6376), 693–697. https://doi.org/10.1126/science.aad6469

(examines genetic basis of autism, bipolar, depressive disorder, schizo, alcoholism. Data from over 700 postmortem brain.

Gandal and their associates, in this article, argue that there is a significant correlation between molecular pathways in different psychiatric disorders. This suggests that there are common underlying causes between the disorders. In this article, the authors examine the genetic basis of autism, bipolar disorder, depressive disorder, schizophrenia, and alcoholism by testing samples from 700 postmortem brains. As a result, they have found that these disorders share dysregulation in genes involved in signaling in the immune system, function of the synapses, and neuron signaling. Keeping these results in mind, the authors have come to the conclusion that there may be and likely are common genetic factors behind these psychiatric disorders.

This text is useful to my argument that genetics play an important role in mental/psychiatric disorders and that genetics may directly cause them because it provides molecular-level evidence of the genetic commonalities between autism, bipolar, depressive disorder, schizophrenia, and alcoholism. The results of the study show that the same genetic pathways and mechanisms are found in the aforementioned disorders, showing the importance of genetic factors in the appearance of these disorders in people.

“a substantial proportion of the genetic risk for psychiatric disorders is attributable to common genetic variation” (p. 693).

“the results suggest that there are important overlaps in the genetic and molecular mechanisms underlying seemingly distinct psychiatric disorders” (Gandal et al., 2018, p. 693).
“These findings support the notion that many psychiatric disorders are genetically related and suggest that current nosology does not accurately reflect the true nature of underlying pathophysiology.” (p. 693)

“the gene expression patterns of ASD, SCZ, and BD [bipolar disorder] brains are more similar to each other than to controls” (p. 695)

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SULLIVAN, DALY, M. J., & O’DONOVAN, M. (2012). Genetic architectures of psychiatric disorders: the emerging picture and its implications. Nature Reviews. Genetics, 13(8), 537–551. https://doi.org/10.1038/nrg3240

(examines genetic architecture of psychiatric disorders)

In this article, Sullivan and O’Donovan discuss the genetic basis of major psychiatric disorders such as schizophrenia, bipolar disorder, and major depressive disorder. They suggest that these disorders, like many others, have complex genetic structures. This means that these disorders are caused by multiple genetic codes and variants that interact with each other and the environment people find themselves in. The authors say that up to 80% of the chance of heritability of these disorders is explained by genetics. This indicates that genetics plays a significant role in these disorders. Additionally, other studies have identified many common genetic variants found in these disorders, and that the expression of the disorders also depends on the combination and interaction of genetic and environmental factors, such as exposure to stress and drugs.

This source is important to my argument about genetics’ role in mental disorders because it shows that there is a significant chance that genetics play a potentially major role in the expression of disorders like schizophrenia, bipolar disorder, and major depressive disorder. The fact that these disorders are estimated to be highly heritable indicates that genetic factors are very influential in the development of these disorders in people. The identification of common and rare genetic variants in people with these disorders through genetic studies also supports the role of genetics in these disorders. Overall, this article proves my argument about genetics and mental disorders, and will be used as evidence to confirm this.

“heritability estimates suggest that genetics explains between 30% and 80% of the variance in liability to major psychiatric disorders” (p. 538).

“the picture emerging from genetic studies is one of highly polygenic disorders, with many common alleles of small effect contributing to risk” (Sullivan et al., 2012, p. 538).

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Smoller, J. W. (2016). The genetics of stress-related disorders: PTSD, depression, and anxiety disorders. Neuropsychopharmacology, 41(1), 297–319. https://doi.org/10.1038/npp.2015.266

In this article, the author is presenting an overview of the genetic factors in stress-related disorders such as PTSD, depression, and anxiety disorders. The author claims that genetic factors play an important role in the development of such psychiatric disorders, and to prove this, family and twin studies, as well as genome-wide association and animal studies are used. Such studies have helped locate several genetic genetic codes associated with such disorders. Smoller also notes that environmental factors can interact with genetic factors to influence the development of the disorders, which is consistent with other sources that I have chosen to use. One quote states that PTSD is, according to estimates, around 30-40% heritable, which suggests that genetics play a large role in the manifestation of the disorder in people. As such, it can be concluded that genetics play an important role in mental/psychiatric disorder.

This source is important to me and my topic of genetics in mental/psychiatric illness because it proves, based on scientific research, that such illnesses can be caused by genetic factors. The article and the author highlight that it is important to consider genetic and environmental factors in order to understand the cause behind the development of diseases and disorders that affect and harm many people in our society. I intend to use this source as another piece of evidence to prove my point, as it once again not only proves the role of genetics in mental illness, but also reinforces other side points, like that mental illness is also based on physical environment and other factors, like upbringing and experiences.

• “There is robust evidence for genetic contributions to these conditions, with heritability estimates ranging from 30% to 70%.” (p. 297)
• “There is growing evidence that genetic factors interact with environmental factors, including traumatic life events and stress, to increase risk for stress-related disorders.” (p. 299)
• “In summary, the genetics of stress-related disorders is complex, with multiple genetic risk factors contributing to risk in a polygenic and heterogeneous manner.” (p. 316)

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Lee, P. H., Anttila, V., Won, H., Feng, Y.-C. A., Rosenthal, J., Zhu, Z., Tucker-Drob, E. M., Nivard, M. G., Grotzinger, A. D., Wang, J. C., Patel, K., Muntané, G., Adams, M. J., Blanchard, M. M., Brown, A., Carlin, J. B., Chen, C.-Y., Chesi, A., … Dale, A. M. (2019). Genomic relationships, novel loci, and pleiotropic mechanisms across eight psychiatric disorders. Cell, 179(7), 1469–1482.e11. https://doi.org/10.1016/j.cell.2019.11.020

Lee and associated authors, in this source, have conducted a genome-wide association study across eight different psychiatric disorders (ADHD, autism spectrum disorder, bipolar disorder, major depressive disorder, OCD, schizophrenia, Tourette syndrome, and anorexia nervosa). The purpose of this study was to identify common genetic codes/loci to gain insight and understanding of the role of genetics in these disorders. In this study, the authors analyzed data from consortiums related to the study of genomics/genetics (such as Psychiatric Genomics Consortium and UK Biobank, from which they used data from over one million people, both with and without psychiatric/mental disorders. As a result of this study, many genetic codes/loci were located which were related to one or more of the disorders, and the authors were able to find significant genetic commonalities between the disorders, especially between schizophrenia, bipolar disorder, and depression.

This source is important to prove the role of genetics in psychiatric disorders because it provides evidence from a massive pool of test subjects and analyzes an array of the most common disorders. The study has revealed that there are common genetic codes shared by the disorders, proving the fact that there is genetic overlap between these disorders, and that there may be common genetic mechanisms that influence the expression of these disorders in people. This study is important also because it provides information which may aid in future research into the genetic component of psychiatric disorders, and may also influence the creations and research for treatment and prevention.

• “We report 109 independent genome-wide significant loci associated with at least one of the eight disorders” (p. 1469)
• “Our results provide support for the polygenic nature of psychiatric disorders, with substantial genetic overlap observed between disorders, particularly between schizophrenia, bipolar disorder, and depression” (p. 1480)
• “These results implicate pathways involved in neural development, synaptic function, and immune system regulation” (p. 1479)