Men who are stressed can pass on anxiety and depression to their children and grandchildren, scientists in Australia have found, in a study which indicates parental advice has been “disproportionately” focused on the health and diet of women.
The study, based on mice which were fed stress hormones, examined the behaviour of the first and second generations of offspring. It found that the later generations – that had no contact with their fathers – showed signs of increased anxiety and depression and that such behaviour may be passed on via molecules called “microRNAs” which affected genetic outcomes.
“People have assumed that apart from passing on half his genome, a father’s job is done,” Professor Anthony Hannan, from Melbourne’s Florey Institute of Neuroscience and Mental Health, told The Herald Sun.
“But … the experience of the father before conception can directly influence the genetic information in the developing embryo.
“High levels of chronic stress have increased in our society, particular in recent decades, so we’re potentially setting up an epidemic of mental health problems in the next generation.”
The study measured stress levels by examining the behaviour of the mice in a range of situations, including putting them in a maze, forcing them to swim in a beaker and depriving them of food. In the maze, for instance, the stressed mice tended to spend more time in the darker side of the apparatus.
“They’re nocturnal so they actually prefer the dark side, and so a more anxious mouse will spend most of its time in the dark chamber,” Professor Hannan said.
“Or you can put them in another chamber where they can go out on an open ledge or they can stay in the more protected part of the maze, and again that’s just another test of anxiety and in both these tests, the offspring showed a disposition to be more anxious in those tests.”
The study, published in the journal Translational Psychiatry, suggested further research was required to explore the effects of a father’s stress and to improve parental health advice.
“At present, peri-conceptual health advice is disproportionately focused on healthy lifestyle and diet in women,” the study said.
“This now appears insufficient, as there is equivocal potential for the male to directly influence the health outcomes of the child.”
Professor Hannan said a study of children of Holocaust survivors found that traits were passed on but further human research was required, such as examining children of people suffering post traumatic stress disorder from car accidents or war experiences.
“This work is difficult to perform in humans however as it’s hard to separate the environment that the children were reared in from the genetic component inherited from their parents, except in adoption studies,” he said.