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A mother's age is often considered a genetic risk factor for offspring, but research is now pointing the finger at fathers, too—particularly when it comes to the mental health of their progeny. Males may have the advantage of lifelong fertility, but as they grow older, the rate of genetic mutations passed on via their sperm cells increases significantly—putting their children at increased risk for psychiatric disorders, especially autism and schizophrenia. Two recent studies support this link at least associatively, but experts remain uncertain if age is the cause of these problems.
The Malaysian Mental Health Survey (MMHS) results, which were published online in March 2011, for instance, revealed that people with older parents as well as those whose fathers were at least 11 years older than their mothers, were at increased risk for certain mental health disorders, including anxiety, depression, obsessive-compulsive disorder and phobias. Offspring whose fathers were 19 or younger when the child was born had just a 9 percent prevalence of mental health disorders. Regardless of paternal age, however, if the father was 11 years or older than the mother, that rate jumped to 24 percent. The greatest risk of mental health disorders—42 percent—was seen in the children of fathers aged 50 and older, with wives at least 11 years younger than their husbands.
The link between paternal age and increased risk of mental illness has long been recognized by practitioners, but researchers are beginning to unravel more details: "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," says Dolores Malaspina, a professor of psychiatry and environmental medicine at New York University and a leader in the field of paternal age-related schizophrenia (PARS).
Sperm gone bad?
Some researchers disagree about whether the connection between paternal age is purely based on internal genomic mechanisms related to the aging process, aka "sperm gone bad," or whether environmental and epigenetic factors also affect outcomes.
"The links between a father's age and mental outcomes is multifactorial. You have to take into consideration epigenetic, psychosocial and biological factors," says John McGrath, a professor of psychiatry of the Queensland Brain Institute at the University of Queensland in Australia.
The epigenetic approach is based on the theory that accumulated exposure to environmental toxins over time causes genetic expression alterations that are passed on to later generations and lead to disease in the children later in life. For example, children of Vietnam War veterans exposed to the herbicide agent orange have an increased risk for spina bifida due to epigenetic changes. And drinking and smoking can have epigenetic effects in offspring.
"We do know that there are operating mechanisms whereby paternal experience over a man's lifetime can shape the metabolic pathways of his children," Malaspina says. The question is whether these changes affect the long-term mental health of older men's children.
Likewise, a psychosocial approach focuses on external factors that might contribute to the expression of certain genes. "Delayed paternity does increase the risk of mental disorders, but genetic mutations may not be causative," MMSE researcher Kavitha Subramaniam said in a prepared statement. "They may behave more like susceptibility factors, so that children of older fathers may overreact and show phenotypic expression of certain diseases when they face environmental stimuli. Whereas those with no genetic liability may not develop mental health disorders."
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28 Comments
Add CommentThis is incredibly interesting, but I'm slightly curious about the effect of base rates on all of this. The prevalence rate for schizophrenia is approximately 1%, and I don't know the frequency distribution for age-at-birth but I'm fairly sure that the majority of parental couples don't involve an 11-year age gap or a father who was over 50 at the time of birth. So, that being said, it makes me wonder what terms like "4.4 times greater" really mean. Is this truly a significant risk, or do base rates and relative infrequencies in the population distort everything?
Reply | Report Abuse | Link to thisThere is some confusing/contradicting math in this article and it leads to ambiguity about the reported data. The author suggests "men aged 35 and older are 0.27 times more likely to have children who eventually develop schizophrenia, compared with men under 35." Does the author mean that such men are 1.27 times more likely or are they in fact less likely? ".27 times" would actually suggest a fraction of the likelihood of men under 35. But, you say .27 times "more likely", suggesting that you mean that men aged 35 and older are in fact 1.27 times more likely, while .27 times would suggest they are in fact less likely. For example, if the likelihood of men under 35 is 1, then .27 X 1 = .27. That would suggest men over 35 produce schizophrenic children 27% of the time that men under 35 do. So, 35+ men would be in fact less likely than men under 35 to produce children who have schizophrenia.
Reply | Report Abuse | Link to thisHere is the full paragraph: "The researchers found that fathers aged 40 and above are 3.3 times more likely than under-40 fathers to have children with autism spectrum disorder, whereas men aged 35 and older are 0.27 times more likely to have children who eventually develop schizophrenia, compared with men under 35. The study did not show any connection between paternal age and bipolar disorder. In the case of depression, the rate was higher not only in the children of men over 40, but also in fathers aged 20 and younger—so it appears that there are different biological and psychosocial mechanisms that influence risk of affective disorders versus risk for autism spectrum disorder and schizophrenia."
Of course, with all this talk of mental illness, there is no mention of the worst mental illness of all -- normalcy. Plus, of course, genetic change is how evolution works, and not something to be avoided at all costs.
Reply | Report Abuse | Link to thisThanks for the math lesson.
Reply | Report Abuse | Link to thisHere's another: Sometimes, less is more.
Rhodinsthinker
Reply | Report Abuse | Link to thisEvolution does work via genetic change but for evolution to occur it must make the person (in this case) better "fit". Schizophrenia and autism spectrum disorders are not noted for their reproductive success but rather the opposite. It's not a matter of avoiding evolution (that is unavoidable) but rather dealing with the genetic change that isn't passed on to the benefit of our species. In the case of schizophrenia and ASD, they have a lot of challenges to their personal survival let alone passing on any genes they possess.
It's amazing the lengths the scientific community will go to to explain an epidemic now affecting one percent of children and almost 2 percent of boys. Blaming the exponential increase in autism on older dads, genetic mutation, and accumulated toxins hardly explains why tens of thousands of parents report that their child was born healthy and was developing normally until they received certain routine vaccinations---vaccinations containing a host of untested toxins like mercury, aluminum, formaldehyde and more. Suddenly these children come down with things like diarrhea, seizures and sleep disorders. Many stop talking and lose learned skills, eventually ending up with a diagnosis of autism.
Reply | Report Abuse | Link to thisMany of us in the autism community question why a neuro-developmental disorder like autism fits under the description of "psychiatric diagnoses" and "mental illness." For decades, experts claimed autism was a solely genetic disorder that children were born with. We were assured that there was no real increase--it was all just better diagnosing by doctors. Suddenly we're hearing that scientists believe there are environmental factors. There are a number of candidates from pesticides, older moms, older dads, too much TV watching, living too close to freeways, having siblings too close together among others. It seems that experts will continue to guess at autism and allow another generation to become its victims.
Anne Dachel, Media editor: Age of Autism
How to publish a dubious article. Start with your conclusion. Gather information. Diddle with the numbers until you get something "statistically meaningful." If for example you get nothing with 45-year olds, try forty-five year olds with blue eyes or forty-five year olds married to 34 year olds. Begin by saying it's a complicated issue; end by announcing more research should be done. Fifteen such articles may get you promoted to Associate Professor of Whatever.
Reply | Report Abuse | Link to this@amdachel: Your pseudoscience has been overwhelmingly debunked by decades of science and countless studies. Every major medical group (CDC, AMA, World Health Org, American Academy of Pediatrics, etc) and 98% of doctors accept that there is no link between vaccines and autism and recommend people get the regular schedule of vaccines. One of the few things known for sure about autism is that vaccines don't cause it. Anti-vaxxerism is a New Age cult/religion, nothing more. Go peddle your nonsense elsewhere, people here at Sciam are too intelligent and informed to buy into it.
Reply | Report Abuse | Link to thisA corollation between factors A and B suggests 3 possibilities. A=>B, B=>A, or C=>A and B, where => means 'causes.' Well I have a couple C=>A and B possibilities in mind. I wonder if this/these study/studies controlled for mental health problems in the father since mental health problems might have delayed their finding a mate. Was this study longitudinal because a snapshot might be clouded by generational differences like willingness to have an abortion in less than optimal circumstances, or to seek a medical diagnosis of mental illness in their children? Of course there are many other possibilities, but these are two that come to mind.
Reply | Report Abuse | Link to thisThe casual use of the term "weird dad" in this article is incredibly discriminatory.
Reply | Report Abuse | Link to thisIt amazes me how people who would otherwise think of themselves as enlightened and against other forms of discrimination will, when it comes to mental illness, use discriminatory terms without a thought. This can even include scientists and journalists.
I struggled with social anxiety disorder for more than 15 years. Finally, after many years, I was able to make significant progress and overcome much of my phobia. Now, at 50, I have a loving girlfriend and hope to marry and have children.
Why must I read, in a scientific magazine, terms like "weird dad" when I had a clinical mental illness that was never my fault in the first place? And why do I have to be labeled in this way when I worked so hard for so many years to over come my problem?
This magazine is not the only place where I have encountered such discriminatory language. I learned the hard way long ago to be very careful about who I reveal my own personal struggle to. Coworkers, managers, even family members are often quick to label and discriminate against people with mental illness, even those who would never otherwise think of discriminating against any other group and who imagine themselves to be forward thinking people.
People that go to enemy doctors are either suicidal or homicidal. Depending who they intend to give the medication.
Reply | Report Abuse | Link to thisDoctors tend to make up diseases to cover up medical incompetence . An example of this is mad cow disease. There is strong evidence that mad cows happened as a result of toxic chemicals used for insecticides. The government made up the feed disorder to cover up the disaster.
Reply | Report Abuse | Link to thisWhere is the strong evidence located? Where are the sources? For an accusation so strong, you need to have the data and sources to back it up.
Reply | Report Abuse | Link to thisSorry but you are pounding on the wrong door with this article. To begin with, although some misinformed persons have located autism in the DSM, autism is NOT a mental disorder. Therefore this artilce holds little
Reply | Report Abuse | Link to thisinfluence, actually none. Autism(for those who don't yet know) is a metabolic disorder affecting every organ in the body. Children with autism suffer from oxidative stress, immune dysfunction, encephalopathy, inflammatory bowel disease etc . Of course since 80 percent of the immune system lies in the gut-the brain will also be affected as it also is an organ in the body. The old man theory(if it were true which it's not) wouldn't suddenly in the last 2 decades present
hundreds of thousands of mutations when years prior to early 1990's -autism was so rare and yet I am sure older men were having babies for years prior to that. Of course, I know some doctors, scientists, psychologists would like to wear the glory of solving the "so-called" autism epidemic(a kind of modern day Galileo) and make some money in the study, but we do not have the answer here. I know-Let's have that never done fully vaccinated vs fully unvaccinated study of children and see the results. There are thousands of unvaccinated children in the US that can be used for the study. Meanwhile, even the silly freeway theory trumps this one.
Maurine Meleck SC
The reader is expected to accept the premise that the results of mental health surveys conducted using populations of Malaysians, Swedes and Dutch can be indiscriminately applied to all other populations?
Reply | Report Abuse | Link to thisPersonally, I reject the assertion that cultural, economic and many other conditions varying for distinct national populations are not factors that influence the results of such studies.
For example, I have to wonder what effects might have been imparted by dismissing respondents in the Malaysian study who did not know the age of their parents...
Since there is a correspondence between the exposure to light and depression, might not Northern European populations possibly be affected by the naturally depressing, very long winter nights?
How can any responsible analysis assert that the results of these studies also apply directly to a cross section of the U.S. and all other populations? IMO - Nonsense!
Actually, "maurinemeleck," there is no evidence that ASD is a metabolic disorder, although certain metabolic disorders are associated with ASD-like symptoms. Also, the vax/non-vax issue has been looked into repeatedly -- there is no connection, although once again there are certain rare metabolic disorders which may be triggered by the fever that sometimes occurs after vaccinations -- or any disease that causes fever. (Anti-vaxers fawn over these cases, since they represent the majority of payouts for "vaccine injury" even though the underlying genetic abnormality eventually would have shown itself in any case) And the idea that "80% of the immune system lies in the gut" has no scientific support whatever.
Reply | Report Abuse | Link to thisAs a child fifty years ago I had symptoms that would easily qualify me for an ASD diagnosis today, including language regression, sensory issues, so-called "stimming" behavior, and so forth. Fortunately I was verbal enough to not be labelled "MR," and eventually, despite extreme social awkwardness and lack of academic success, I worked things out with help from my parents -- who were challenged and a bit confused, but were always supportive and didn't play the blame game I see parents with ASD kids doing today.
Diagnostic substitution, institutional pressure to label "problem children," obsessive parenting and increased pressure for children to conform -- there's your "epidemic." As someone who was "on the spectrum" back before we were even supposed to exist, I have a message for you: we've always been here.
The theory look true at least in my case. I suffer from bipolar disorder and am a son of older age father
Reply | Report Abuse | Link to this@Openeyes999 although your conclusion is right that a lot of myth are debunked; my experience tells me that it is real hard to get good information to the public. Even doctors and patient organizations suffer from a lack of up to dateness.
Reply | Report Abuse | Link to thisThat having said I would rather seen that you invite the other person to possible information pages where science research can be found. I know it is for the die hards to wrestle through these complicated things, but it has to be done if you want to be a well informed citizen.
And science is not perfect per se. It is still done by people with their personal styles. So it would be nice if you kept your answer in the same style as 'too intelligent and well informed' people do; with style and good argumentation. Just because doctors and scientist have caused the problems of wrong conclusions in the first place, leaving the next generation scientist to clean up the mess.
The only reference to "weird Dad" was to prove YOUR point, precisely. Would you rather the topic not be addressed at all?
Reply | Report Abuse | Link to this"That's what I would call a systematic bias," he says. "The idea that dad is weird and the kids are going to get his weird genes has been around for some time, but the evidence suggests there is more going on."
The answer, my friends, lies in A Monty Python song :
Reply | Report Abuse | Link to this«Every sperm is sacred.
Every sperm is great.
If a sperm is wasted,
God gets quite irate.»
I'm a bit surprised this hasn't come up yet, though it's clear those who comment mostly are from a broad scientific community. It's refreshing to realise all Americans are not hard-core creationists...
As a father over 50, with a spouse more than 11 years my junior, is it just good luck that my son seems to be "normal"? And yet my dad didn't start his family until he was 50... and there's only 9 generations separating me from my ancestor who was born in 1670. In the words of the philosopher Hank Jr., it's a family tradition, with seemingly no ill effects (aside from a love of country music coupled with an inability to sing in tune).
Reply | Report Abuse | Link to thisDrawing conclusions pertaining to genetic damage from the underlying studies borders on junk science, no such connection can be correlated with any observed change in spermatozoa related to paternal age, compared to similar well-established correlations that can be shown with older ova in women (which corresponds to increased incidences of birth defects, Down's syndrome etc.) Moreover there are simply too many more likely confounding factors. For example it can probably be shown that older men have children with older women, a man in his 50's is probably more likely to father a child by a woman in her late thirties or early forties than in her twenties. Then there is the "weird" parent theory advanced in the article, that these genetically impaired of parents simply take longer to parent children. Or perhaps it is harder to grow up with an older father, or perhaps older/younger couples are weirder. All could be, but these and other confounding factors combined with the fact that spermatozoan changes can be correlated with increased incidence of psychiatric problems make it silly to attribute to aging sperm. You would also expect a greater provable correlation with incidence of psychiatric problems. The change in incidence of schizophrenia is almost negligible, while the incidence of autism is still relatively remote.
Reply | Report Abuse | Link to thisWhat would be better evidence would be a study limited to children borne by women at under age 30 and fathered by men over 50, and limit the conclusions to genetically-linked disease; this would greatly eliminate confounding factors.
From my limited understanding of general genetics, if you have several generations of children of older parents, you are helping to increase the over all life expectency of humanity via natural selection. The side effect will tend to be that those that don't adapt to older parent ages will tend to not reproduce as much.
Reply | Report Abuse | Link to thisAs a weird dad, I don't find the term weird dad to be insulting at all. I'm not an older dad and had my children in the "prime" age range with a woman within a year or two of my own age. Never the less, I'm pretty darned strange.
Reply | Report Abuse | Link to thisAs for the autism/vaccine thing - Kill 75 out of every 100 children or have 1 or 2 out of every 100 have a mental issue. Not a hard decision to make. When your unvaccinated child dies from a disease you chose to not protect them from, just remember it was your fault and you killed them.
well this research can easily disproved. If the study is done on children who already suffer from autism in US and finding the age of the father. If you find even couple of cases of fathers in their 20's whose offspring has autism. the whole theory falls apart.
Reply | Report Abuse | Link to thisyou dont have to go to mice to do the research just examine the current autism childrens and find the age of the fathers.
Older Dads have more mercury fillings and mercury vaccines cause autism. Obviously , mercury is the villain and doctors are the mediator.
Reply | Report Abuse | Link to thisand WT7 fell because of small fires.
Reply | Report Abuse | Link to thisMost mental conditions are treatable . Not by pharma.
Reply | Report Abuse | Link to this