What the research says.
Much of scientific literature seeks to address heritability and genetic links to certain mental health disorders. To start, it is important to understand what is meant by heritable. The Merriam Webster Dictionary defines the word as meaning “the proportion of observed variation in a particular trait (such as height) that can be attributed to inherited genetic factors in contrast to environmental ones” (2022).
A 2017 twin study found schizophrenia to be 79% heritable (aligned with findings of previous research), and when expanding illness outcomes to schizophrenia spectrum disorders, the heritability estimate was 73% (Hilker et al., 2017). A study conducted in 2018 explored the potential multigenerational transference of psychiatric disorders, specifically honing in on bipolar disorder; the study found that out of a sample size of nearly 1,000, the illnesses seen in prior generations were associated with the same type of illness in offspring of a bipolar patient, including depression, alcohol and substance use, and bipolar disorder (Post et al., 2018). Further, there was an impact across multiple generations such that depression in grandparents and/or great grandparents increased the risk of depression symptomatology in the offspring from 12.6% to 41.4% (Post et al., 2018).
With this being said, certain environmental factors may combine with heritable traits to catalyze and elicit mental health disorders. These could be stress, trauma, sleep deprivation, substance use, exposure to toxins, along with a multitude of other environmental factors that may influence the development of mental health disorders. Prenatal exposure to certain substances and hormones also fall under this category, as the womb is an environment in and of itself.
Though mental illness runs in families, it is important to note that this doesn’t mean that you or someone else in your family will surely be diagnosed with a mental health disorder. Rather, it may serve to inform us of the importance of attending to mental health concerns as well as investing time and energy into our own mental health as a preventative measure.
Good Mental Health Practices.
It is important to be cognizant of our family’s mental health history in order to develop an understanding of how we can better care for our own mental health. Exercising, leaning on a strong support network, getting good sleep, practicing gratitude, practicing optimism, and utilizing mindfulness are all practices that have been studied to contribute to better mental health outcomes. Another recommended mental health practice is seeking professional help when we need extra support. Psychiatrists can prescribe psychotropic medications to address symptoms we struggle with and psychotherapists can work with us to develop coping skills to better navigate our mental health challenges.
References
Hilker R, Helenius D, Fagerlund B, Skytthe A, Christensen K, Werge TM, Nordentoft M, Glenthøj B. Heritability of Schizophrenia and Schizophrenia Spectrum Based on the Nationwide Danish Twin Register. Biol Psychiatry. 2018 Mar 15;83(6):492-498. doi: 10.1016/j.biopsych.2017.08.017. Epub 2017 Sep 1. PMID: 28987712.
Merriam-Webster. (2022). Heritability definition & meaning. Merriam-Webster. Retrieved January 29, 2022, from https://www.merriam-webster.com/dictionary/heritability
Post, R. M., Altshuler, L. L., Kupka, R., & McElroy, S. L. (2018). Multigenerational transmission of liability to psychiatric illness in offspring of parents with bipolar disorder. U.S. National Library of Medicine. Retrieved January 29, 2022, from https://pubmed.ncbi.nlm.nih.gov/29926532/