Children of Older Dads have High Risk of Mental Illness

Children of older fathers have a higher risk of mental illness, according to a new Australian study.

The study, conducted by researchers at Queensland Brain Institute (QBI), was based on data from over two million people.

"The study followed people with a broad range of mental disorders including schizophrenia, mood disorders, neurotic, stress-related, eating disorders, personality disorders and a range of developmental and childhood disorders born from 1955 to 2007, for the equivalent of 42.7 million person years," Professor John McGrath, lead author of the study, said in a news release.

"We found that the overall risk for psychiatric disorders, in particular mental retardation, autism and schizophrenia, increased for those born to a father over the age of 29 years," he added.

Researchers also found that children of young mothers had a higher risk of neurotic and stress related disorders.

Previous research has shown that older dads are more likely to pass on autism-linked genetic mutation to their children. There was another recent study that claimed men who became dads at an older age had higher chances of having a grandkid with autism.

According to McGrath and colleagues, de novo or new mutations in the sperm might be associated with some of the conditions. De novo mutations mean that the changes in genes aren't inherited.

In other words, the biological reproductive clock doesn't just tick for women, but also for men.

McGrath and team added that parental age and mental illness in the children might be affected by several other factors.

The study A Comprehensive Assessment of Parental Age and Psychiatric Disorders, is published in JAMA Psychiatry.