Older Dads May Increase Risk of Mental Illness in Kids

According to The Malaysian Mental Health Survey (MMHS), an older father may increase the risk of his child being diagnosed with a mental illness.

It has been well known for some time that a woman’s age matters greatly when it comes to giving birth to a child. Every year a woman ages, chromosomal abnormalities increase in her eggs. As a result, a woman who is 30-years-old has only a 1 in 1,000 chance of giving birth to a baby with Down syndrome, but the risk climbs every year she ages—by age 35 it’s 1 in 400, and by age 40 it’s 1 in 100—until age 50, when the risk is its highest, 1 in 10.

Numerous studies have been conducted in the past with the intent to find a similar link between older fathers and their offspring, but thus far, no definitive links have been made, only suggestions.

“We have known that the children of older men have higher susceptibility to sporadic disease since the 1970s, but there has been an explosion of research in this area," reported Dolores Malaspina, professor of psychiatry and environmental medicine at New York University, leader in the field of paternal age-related schizophrenia (PARS).

Recently, the MMHS concluded that children suffered only a 9% risk of mental health disorders (such as obsessive-compulsive disorder, depression, various phobias, and anxiety) when the father was 19-years-old or younger at the time of conception. However, the percentage increased to 42% if the father was 50 years or older at the time of conception and the mother was at least 11 years younger.

The reasoning is not very clear, as many experts argue over whether it’s a natural aging process or connected to exposure to toxins in the environment, but the increase in risk may be connected to the gradual accumulation of mutations in the father's sperm.

A woman is born with all the eggs she will carry for her life already in her ovaries, but sperm multiplies throughout a man’s life. "By the time a man is 40, his sperm cells have undergone 660 cell divisions, and 800 cell divisions by age 50," said John McGrath, professor of psychiatry of the Queensland Brain Institute at the University of Queensland in Australia. With so many cell divisions, it’s inevitable that mutations will occur every so often, and then accumulate with time.

Still, some researchers theorize that accumulated exposure to environmental toxins over time can lead to genetic alterations which are handed down to later generations, causing disease in the children later in life. Children of Vietnam War veterans who were exposed to the herbicide agent orange, for instance, were at an increased risk of spina bifida, and it is no secret that drinking and smoking can affect a person’s offspring.

"The links between a father's age and mental outcomes is multifactorial. You have to take into consideration epigenetic, psychosocial and biological factors," said McGrath.