The age of the parents at the time of a child's birth could be associated with the child's risk for developing psychiatric disorders, including mood disorders and schizophrenia, according to a new study.
The findings showed that risks are higher especially for the offspring of teen parents and older fathers.
Parental age may be tied to psychiatric disorders because of "de novo (or new) mutation in the developing sperm cell," study researcher John McGrath, a professor at the University of Queensland Brain Institute, said in a statement.
The JAMA Psychiatry study, which involved following 2,894,688 people from Danish health registers from 1955 to 2007, shows that children born to very young mothers (between ages 12 and 19) have a 51 percent increased risk for a psychiatric disorder, compared with children born to mothers between ages 25 and 29. However, there was no association between being born to an older mother (age 30 and older) and risk of a psychiatric disorder. However, the researchers did find an association between being born to a mother age 40 to 44 or a teenaged mother, and an increased risk of the offspring having intellectual disability.
As for dads, children born to teenage fathers had a 28 percent higher psychiatric disorder risk, and children born to older fathers (ages 45 and older) had a 34 percent increased psychiatric disorder risk, compared with fathers between ages 25 and 29.
"Teenaged parenthood has been associated with a broad range of adverse health, educational, social, and crime-related outcomes in the mothers and their offspring. However, ascribing these outcomes directly to the ages of the parents vs a wide range of confounding factors is difficult," the researchers wrote in the study. "As with many behaviors, young parenthood as a trait can be identified across several generations, further highlighting the complex and socially patterned web of causation that may link the variables of interest."
While researchers generally found that all psychiatric disorders seemed tied to parental age at the children's birth (with the exception of bipolar disorder, eating disorders and schizoaffective disorder), there were some disorders that seemed especially tied to parental age.
For instance, kids born to teen parents had a higher risk of disorders tied to substance abuse, as well as behavioral and emotional disorders and hyperkinetic disorder. Kids born to teen parents, as well as older fathers, also had a small, but significant, increase in risk for mood disorders.
Kids born to fathers age 45 and older had a higher risk of schizophrenia, personality disorders, and stress-related disorders.
The findings suggest that maternal age is not just a factor in childbirth -- paternal age may matter, too, researchers said.
"Our new studies suggest that age-related mutations from the father may impact on the mental health of the offspring," McGrath said in the statement.
In 2008, an Archives of General Psychiatry study showed that older fathers may have an increased risk of having a child with bipolar disorder. That study was based on data from 13,428 patients in Swedish health registers.