Children with older fathers are more susceptible to mental health disorders an international study led by QBI has found.

Led by Professor John McGrath, the team used Danish health registers to examine the maternal and paternal age of 2,894,688 offspring at birth.

“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 McGrath said.

“Recent genetic studies have confirmed that the offspring of older fathers have more de novo (or new) mutations.

“Our new studies suggest that age-related mutations from the father may impact on the mental health of the offspring.” he said.

In short, the biological clock ticks for men, as well as women.

“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,” Professor McGrath said.

“De novo mutations in the developing sperm cell may contribute to an increased risk for a surprisingly wide range of mental health disorders, including schizophrenia, autism and mental retardation.”

When analysing the data, the team also confirmed a link between the offspring of younger mothers and substance abuse disorders, hyperkinetic disorders and mental retardation.

“For the broad range of neurotic and stress related disorders, the offspring of teenage mothers were at the highest risk,” Professor McGrath said.

The study demonstrates a more complex and nuanced pattern of association between maternal and paternal ages and the risk for mental disorders in their offspring.

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