One researcher has described the link as follows:
We found that paternal age explained over a quarter of the risk for schizophrenia in the population. At the time, people were skeptical. But the findings have been replicated many times now, and not a single study has failed to find this strong relationship between father's age and the risk for schizophrenia. And at this point, other explanations for the relationship have been ruled out, including social factors in the family, prenatal care, and parental psychiatric ailments. There simply seems to be a relationship between paternal age and schizophrenia risk.
Wow – one quarter of the risk for schizophrenia explained by paternal age? I’ll admit that these types of studies are not my area of expertise, but from my review of some of these studies, I’m willing to buy that paternal age is a significant risk. These findings have indeed been replicated on numerous occasions.
One of the main researchers in the area, Dolores Malaspina (quoted above), has said that findings such as this should not discourage parents from having children at whatever age they choose. I am not in agreement – older parents should be made aware of the risk and make an informed decision.
Why the effect? Here’s what seems to be a decent explanation…
"Every cell division makes a copy of DNA," [researcher] Gavrilova says. "And the same thing happens with the next division and this final copy is of less quality. This can introduce a slight risk of error in the genetic material of the new sperm. You can call it a kind of copy error.
The longer a man ages, the greater the chance of sperm mutations that could lead to schizophrenia or other problems in offspring.
There is also research linking autism to older fathers. It appears that such information is not widely known. I was certainly not familiar with it until recently. Consider the trends in Western societies – fathers having children at older ages is likely leading to a decent sized increase in rates of schizophrenia, autism, and perhaps other problems as well. While this is excellent news if one is in the antipsychotic business, is this really good news for everyone else?
Shouldn't this information be more widely discussed?
Hat Tip: Just Noticeable Differences.