New research from the University of Edinburgh suggests that children whose grandmothers were stressed during pregnancy have a greater chance of developing mental-health disorders later in life.
Through a study done on rats at Edinburgh’s Roslin Institute, depression and anxiety has now been linked to genes.
Whilst it was previously known that stress during pregnancy could affect first generation offspring, the researchers discovered that prenatal stress can affect brain development and behavior in future generations.
Speaking to The Student, the principal investigator of the study Dr Paula Brunton described a few of the many tests they used to investigate their hypothesis.
Dr Brunton described one such test as “the sucrose preference test”. Brunton said: “This test measures anhedonia, which is one of the (many) symptoms of depression. Here rats are given the option of drinking normal water or a sugar solution, the idea being that the sugar is pleasurable and rewarding.
“Typically rats show a major preference for drinking sugar over water, so if we see rats where this preference is lower or even absent, this is an indicator of anhedonia and interpreted as a depressive-like behaviour – again these types of tests have been previously validated in rats using anti-depressants. However in our study, the rats from control and stressed grandmothers showed similar responses.”
Dr Brunton continued: “This is the first study to show that stress during pregnancy can be transmitted to the second generation offspring (e.g. the grand-offspring) without further intervention in the daughters.
“It indicates that some mental health disorders may have early life origins. For example, an adverse environment in the womb- as a result of exposure to maternal stress hormones for example – may predispose the unborn child to mood disorders in later life (there are also changes in gene expression in the brain), but moreover the grand-offspring also seem to be affected (with similar changes in gene expression in their brains).”
The UK Mental Health Foundation estimates “about a quarter of the population will experience some kind of mental health problem in the course of a year,” and says depression affects 1 in 5 older people. In addition, “about 10 percent of children have a mental health problem at any one time.” Their figures also reveal that “self-harm statistics for the UK show one of the highest rates in Europe: 400 per 100,000 population.”
The studies being executed at the Roslin Institute have provided an insight into one possible cause for such high rates of mental-health disorders, and will help address possible solutions and treatment to certain cases.
Dr Bruton discussed further investigation to be taken in the study, telling The Student: “Next, we would like to understand the mechanisms responsible for maternal stress affecting gene expression in the offspring’s brain and how this effect is transmitted across generations. Also we want to investigate whether the negative effects of stress on the offspring can be prevented or reversed.”
Image: Il-Young Ko