Frequently Asked Questions on Genetics & Mental Illness
Can you inherit mental illness?
The causes of mental illness are complex and not completely understood. They involve an interplay of genes and environment, which includes the environment of the womb as a fetus develops, as well as biochemical changes during brain development. Genes certainly contribute to the development of mental illness, but it’s not likely that any single gene passed from parent to child is responsible. Rather, it appears that variations in many genes, combined with other factors, such as stress, work together to raise the risk of developing a brain and behavior disorder. However, even gene variations with the strongest links to mental illness only raise the risk by very small amounts.1
Forward-thinking research on the genetics of mental illness is continuing on many fronts. For example, scientists have demonstrated that a genetic component to schizophrenia involves “jumping genes” — bits of DNA that can move around and insert themselves into genes and disrupt their function. Jumping genes can either remain silent, doing nothing; they can churn out their own genetic products; or they can alter the activity of neighboring genes, sometimes with deleterious effects. This work, which is just one of many projects on the genetics of mental illness supported by NARSAD Grants, was led in part by two-time NARSAD Grantee, Tadafumi Kato, M.D., Ph.D., Senior Team Leader for Molecular Dynamics of Mental Disorders at RIKEN Brain Science Institute in Japan.2
Are there tests to find out if you have a genetic predisposition to mental illness?
There are tests on the market now that sequence all of a person’s genes, or “genome” for $1,000 — inexpensive, compared to the $400 million price tag just 10 years ago. Companies that sell these tests suggest they can provide information about a person’s risk of developing specific diseases, based on variations found in their genes. But according to Francis Collins, M.D., Ph.D., Director of the National Institutes of Health, “unless you’re dealing with a specific disease, these tests can be pretty hard to interpret.” Dr. Collins formerly led The Human Genome Project, a massive scientific project to map and sequence all of the human DNA and determine its function.3
Genetic research might make it possible, one day, to provide a more complete picture of whether a person will develop a particular kind of mental illness based on his or her genes. That day isn’t here yet, but progress is being made at research labs around the world every day. Some cutting edge research in this area is being led by two-time NARSAD Grantee Daniel R. Weinberger, M.D. at the Lieber Institute for Brain Development.4
Are there any genetic tests to determine the best treatment for someone with a mental illness?
Doctors call this “personalized psychiatry,” prescribing specific psychiatric treatments to patients based on their individual genetic makeup and biology. Currently, most psychiatrists prescribe treatments based on population-wide statistics, not individual profiles. Researchers are now focusing on identifying genetic biomarkers (biological predictors) for mental illness that will make the individualized tests possible. Oncologists already practice personalized medicine. For instance, in breast cancer, doctors can determine the specific tumor subtype a patient has by examining tissue from the tumor and prescribing effective “targeted” treatments based on their findings.
Of course, there is no way to obtain brain tissue samples from, say, a living child with autism. But research shows there is a way around this. Shinya Yamanaka, who won the 2012 Nobel Prize in Physiology or Medicine, has been reprogramming human skin cells to become stem cells and thus all kinds of other cells, including the cells of the nervous system. By taking skin cells from an autistic child and turning them into neurons, we might be able to understand what kind of autism the child has and what chemical fixes might help.5