Study Exams Autism’s Link To Antidepressants
Is There a Link Between Women Taking Antidepressants While Pregnant and Autism?
Wall Street Journal
By SHIRLEY S. WANG
A preliminary but provocative new study finds women who take antidepressants during pregnancy have a moderately higher risk of having a child with autism, according to a paper published in the Archives of General Psychiatry.
Another study, published in the same issue of the journal and examining autism in pairs of identical and fraternal twins, finds that environmental factors play a greater role than previously believed in the development of autism, underscoring the need to understand nongenetic causes of autism.
The research on antidepressants and autism is thought to be the first to look for and identify such a link. Results indicated a doubling in risk of autism if the mother filled a prescription for antidepressants at any point in the year before delivery. The risk tripled if she filled the prescription during the first trimester of pregnancy.
The findings don't speak to whether antidepressants cause autism, and the work needs to be replicated, the authors cautioned. The data, though, do indicate that the drugs have "possible adverse outcomes in children" and deserve further study, said Lisa Croen, first author on the study and an epidemiologist in the research division of Kaiser Permanente Northern California, the big managed-health plan.
"A lot of people might get a little worried about these findings and change something they're doing—which they shouldn't. It indicates to us that there's more to look at," said Dr. Croen, who also is an author on the twins study.
The researchers, sifting through medical records, identified 298 children diagnosed with autism or a similar disorder and looked back in time to the characteristics of the mothers. These children and mothers were compared with 1,507 children without autism and their mothers.
The relationship between autism in the child and the mother's use of antidepressants—predominantly the category known as selective serotonin reuptake inhibitors, or SSRIs—remained even after researchers statistically accounted for the effects of other factors that might be related to either condition, such as maternal age, ethnicity and education, as well as baby birth weight and where the baby was born. In the twins study, a team including researchers from the University of California San Francisco Institute for Human Genetics, Kaiser Permanente and the California Department of Public Health identified sets of twins born in California between 1987 and 2004 in which at least one twin was diagnosed with autism or a related disorder. They conducted genetic testing on 192 twin pairs to determine whether they were identical or fraternal and recorded whether each individual qualified for an autism diagnosis.
Then they compared autism rates in fraternal twins versus identical twins, when one twin had it and also when both twins had it. If autism were a completely genetic disorder, both twins in each identical-twin pair would have it, the researchers figured. And if it were caused completely by environmental factors, the autism rates in fraternal twin pairs and identical twin pairs would be the same.
The results indicate that roughly half the risk of autism was accounted for by environmental factors—far more than detected in previous studies, according to Joachim Hallmayer, psychiatry professor at Stanford University School of Medicine and first author on the study. It "shows clearly that we have to take both environment and genes seriously, and we have to study much more the interactions between genes and environment," Dr. Hallmayer said. Environmental factors shared by twins, particularly during the prenatal period and right after birth, may contribute to autism, he said.
In the antidepressant study, researchers tried teasing apart whether the mother's mental state or the antidepressants were linked with autism. The results indicated an association with the treatment, not with the mother's mental state.
If the pattern can be replicated in a broader population of children, the findings "will add to the growing list of cautions about exposing children and adolescents to medications without a very clear demonstrated need," said John March, director of neurosciences medicine at the Duke Clinical Research Institute, who wasn't involved in the study. Because of limited information in the medical records, researchers weren't able to look at other important factors that might also affect fetal development such as ultrasounds and pain medicines, he added.
Previous research has shown that people with autism have female relatives with a greater likelihood of depression or anxiety. So what looks like a link between antidepressants and autism could actually be a genetic predisposition to this cluster of conditions, said Fred Volkmar, director of Yale University's Child Study Center, who wasn't involved in the current study.
Doctors and patients must weigh the risk of taking antidepressants in pregnancy against risks to the unborn child of untreated depression in the mother. A woman who is depressed may not eat regularly or keep prenatal checkups—possibly putting her baby at more risk than if she took antidepressants, said Mason Turner, Kaiser Permanente San Francisco's chief of psychiatry.
Medicated Moms
Use of prescription drugs in the first trimester of pregnancy:
- Antidepressant use grew to about 7.5% of pregnant women in the 2006-2008 period, up from 5% in 2000-2002.
- Until 1990, less than 1% of pregnant women used antidepressants in the first trimester.
- Since 1976, use of all types of prescription drugs among pregnant women more than doubled.
- About half of women reported that they took at least one prescription drug during pregnancy.
Source: Allen Mitchell, Slone Epidemiology Center at Boston University and colleagues; American Journal of Obstetrics and Gynecology.
Write to Shirley Wang at shirley.wang@wsj.com
South Korean Study Sends Autism Rates Skyrocketing
By Bruce Bower, Science News
South Korea just sent autism prevalence rates surging north. Autism spectrum disorders affect an estimated 2.64 percent of the nation’s schoolchildren, or about 1 in 38 youngsters, a new study finds.
That’s a considerably higher figure than has been reported in the United States, England and elsewhere, where prevalence estimates range between 0.07 percent and 1.8 percent. A 2006 report from the U.S. Centers for Disease Control and Prevention estimated that 1 in 110 children had an autism spectrum disorder, at that time considered a surprisingly high rate.
South Korea doesn’t have an unusually high number of autism cases, says Yale University psychiatrist and study director Young-Shin Kim. Previous studies generated prevalence estimates from medical records of children who had been diagnosed with or showed signs of autism spectrum disorders. Her investigation, published online May 9 in the American Journal of Psychiatry, screened a representative sample of more than 23,000 South Korean 7- to 12-year-olds regardless of whether they had any record of symptoms.
“It seems that many children with autism spectrum disorders have been here all along but haven’t been counted in previous studies,” Kim says.
Prevalence estimates for any ailment based on population surveys are higher and more accurate than those based on data from people already known to have relevant symptoms, says anthropologist and study coauthor Richard Grinker of George Washington University in Washington, D.C.
About two-thirds of South Korean kids diagnosed with an autism spectrum disorder attended public schools where their condition had gone unrecognized and untreated in highly structured classrooms, Kim’s team concludes. Most of these children experienced disorders such as Asperger syndrome (SN: 8/12/06, p. 106) that primarily involve social difficulties. Boys received these diagnoses more than twice as often as girls. All kids with these conditions displayed social impairments severe enough to merit some type of intervention, adds Kim.
Autism, which includes social, intellectual and behavior problems, was the most common diagnosis among South Korean children in special education classes and with registered disabilities. This condition affected boys five times as often as girls.
Cultural factors, such as South Korean parents and clinicians having especially strict definitions of “normal” child behavior, might have influenced the results, remarks psychologist Catherine Lord, director the University of Michigan Autism & Communication Disorders Center in Ann Arbor. But Grinker says the study design addressed such cultural factors.
“This is a solid study and should motivate much further work,” Lord says.
Kim and her colleagues worked from 2005 to 2009 in the city of Goyang, near Seoul. Most participating children attended public schools and had never received special education or psychological services.
A U.S. population survey of autism spectrum disorders needs to be conducted, comments psychologist Geraldine Dawson, research director of Autism Speaks, a private research and advocacy organization in New York City that partly funded the $750,000 South Korea study. “Until then, we won’t know the true extent of these disorders here."