Posts Tagged ‘ environment ’

Why Is Autism So Common Now?

Monday, April 1st, 2013

Autism RibbonIn 1980, the rate of autism was typically quoted as 4 in 10,000. The most recent rate reported is 1 in 50. While it is difficult to get a precise estimate, it’s abundantly clear that rates of autism have increased dramatically since 1980 – and in fact over the last decade. So what has changed?

There are a number of factors that have brought the startling levels of autism to our attention. These include:

Better Awareness: In 1980, autism was first introduced as a separate diagnostic category in the third addition of the Diagnostic and Statistical Manual of Mental Disorders (DSM). Prior to that time, clinicians using the DSM applied other categories such as childhood schizophrenia. Since 1980, there has been extraordinary growth in awareness – both for professionals and parents alike. This is particularly so over the past decade. Advocacy groups have done an admirable job of helping us understand what autism is (and isn’t). Pediatricians now screen for early warning signs – as do parents. These actions have all led to a much greater awareness of the symptoms of autism which undoubtedly translates in more proper diagnoses being made. In addition, the increased awareness has permitted older kids to be diagnosed more properly when the signs earlier in life were not recognized as autism.

Expansion Of The Symptoms: In parallel with efforts to increase awareness, diagnostic changes that recognized autism as a spectrum – now referred to as Autism Spectrum Disorder (ASD) – helped capture the wide range of symptoms that go beyond “classic” autism. Including a much broader representation of social, communicative, and repetitive/stereotyped behaviors certainly helped recognize the disorder in many youth who would not have been diagnosed in past years. Of course, there is debate about how the changes in the upcoming DSM-5 may result in a reduction in the rate of diagnosed ASD in the future. But up until now, recognizing the variation in symptoms that can characterize ASD has certainly been a factor in understanding how common autism really is.

Changes In Etiological Factors: Less understood is the role of new causative factors that increase risk for ASD. Much attention is being given to a large number of potential environmental contributors. There is the suggestion that specific genetic mutations that may be linked to autism – and associated with paternal age – are more common in the population because of average increases in paternal age over the last few decades. Much of this work, though, is work in progress, as it is believed that ASD typically results from the combination of a number of environmental and genetic risk factors. But many researchers operate under the assumption that there are both environmental and genetic risk factors that may be increasing in the population, though they remain elusive.

So, since 1980, what we have learned? We know now that autism is very common, is best thought of as a spectrum that includes substantial variation in how symptoms are expressed, and may be influenced by increasing levels of risk factors that are not well understood at this time. For all these reasons, it is critical that we keep researching the causes of autism, and continue to promote awareness of the early signs and symptoms in order to support early diagnosis and intervention.

Image: Autism Awareness Ribbon via Shutterstock

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Same Genes, Different People: A Tale Of Two Twins

Friday, October 5th, 2012

I’ve been writing a lot about the complexities of determining how genes influence our behavior. The latest view from the genetics field is that the picture is getting more and more murky with increasing attention given to the multitude of ways in which DNA gets expressed. Despite that, we continue to get bombarded with suggestions that single genes are completely deterministic for highly complex human behaviors, like for example wanting to be a mom (click here for my take on the “mom gene”). The reality is that DNA is important and can be influential – but it is typically far from deterministic and all kinds of experiences can shape how DNA is expressed and have effects that go beyond what resides in an individual’s genome. There is no greater example of that than considering how identical twins can end being very different people even though they have the same DNA. To that end, blogger/editor Heather Morgan Shott (from High Chair Times, one of my personal favorite blogs out there) and her twin sister Erin Diebert graciously agreed to answer some questions on their experiences growing up as twins – and their recognition that they were, in fact, different people.

Note: Not Heather and Erin

1) Were you guys very similar when you were young? Did people confuse you? Were you dressed alike?

ERIN: Heather and I played together a lot before we entered elementary school. My mom dressed Heather and I exactly the same through first grade. After first grade, we chose to dress differently. Some people confused Heather and I.

HEATHER: We had very different personalities from birth. I was very impatient and wanted things the way I wanted them immediately, and Erin was more patient. I was the extrovert, she was the introvert. She worried a lot, and I was more carefree. As we grew older, some similarities did emerge; I suspect it’s a nature vs. nurture thing. Our differences as babies and toddlers were our natural personalities, whereas traits emerged as we got older based on how we were parented. We’re both worrywarts who try too hard to please other people (our mom is impossible to please and very highly strung).  We’re both ambitious (we were raised by a single mother who worked two jobs to support the family).

Our mom did dress us alike until first grade—that’s when we started Catholic school and were forced to wear uniforms. I suspect that she just decided to let us wear what we wanted when we weren’t in the classroom. And indeed we developed our own styles. Erin dresses for comfort, I dress for style.

People have confused us and excessively compared us. In college, we have totally different majors (and therefore different classes) and it wasn’t unusual for a professor to mistake one for the other out on campus. (We went to the same college.) The comparisons started around puberty when Erin became the “chubby” twin. It was awful. She struggled with her weight for some reason, whereas I didn’t and people always brought it up.

2) Did your parents make a point of raising you differently? Did you have different teachers?

ERIN: When Heather and I entered Fourth grade, we were put in separate classes.

HEATHER: We also had very different interest emerge, and those led us in separate directions. I was super immersed in the tennis team and the school paper. Erin was more introverted and spent her time studying. I excelled in English, Erin was excellent at science and math. And frankly our parents were so steeped in marital troubles for most of our childhood, even beyond the time they divorced (we were 8) that I don’t think they gave much thought to the importance of raising us to be individuals.

3) When did you start to notice (or looking back see now) that you were different people (different interests, abilities)?

ERIN: Heather and I knew that we were different very young, however, we enjoyed playing together when we were young. We felt very fortunate to have an instant “play date.”

HEATHER: Our differences were very well defined by the time we hit middle school. I was perceived as the mischievous one (and, OK, I was) whereas Erin was the one who always followed along. For example, one time Erin and I were preparing to be spanked. I decided that we’d both put a book down our pants so that the whacks didn’t hurt. My mom took Erin to spank, my dad took me. Fortunately for me, my dad thought my little trick was hilarious and he removed the book and hugged me. Erin, on the other hand, got whacked twice as hard. I was also the one who was in charge of setting up all the social plans, while Erin followed along. Erin, on the other hand, made sure that we signed up for ACT prep classes, etc. She kept me on track academically—or, at least, much more on track than I would have been at that age left to my own devices. I just wanted to write, I didn’t care about most of the subjects in school!

4) Did you guys try to “deidentify” when you were young? Or during your teens? (Some twins deliberately try to carve out individual paths)

ERIN: We tried to deidentify from fourth grade and older.

HEATHER: Agreed—especially me. I was the rebellious twin.

5) Any other insights on why you are different?

ERIN: Heather is very outgoing and confident. She joined a sorority in college. I’m also outgoing, but can be introverted at times. Heather likes to stay up late. I usually go to bed earlier. I have a medium group of close knit friends. Heather has many friends, some  of which are close friends.

HEATHER: At this point, a lot of our differences have to do with nurture. Erin still lives in the town where we grew up (Columbus, Ohio); I’ve lived on the East Coast for over 14 years.  I like big city life, and she prefers a more quiet existence.

6) How do you think you are very similar?

ERIN: We are both very compassionate and have had to deal with some very difficult issues going up. Our parents got divorced when we were 8. Our father chose to be out of our lives starting when we were in our early pre-teen years.

HEATHER: Agreed, along with a couple of points that I made above.

Thanks to Heather and Erin for sharing their stories and insights! 

Image of identical twins (not Heather and Erin) via

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Better Environments And Less Drugs For Kids With ADHD?

Sunday, January 29th, 2012

A provocative essay published in the New York Times suggests that Ritalin (and other stimulant drugs) is essentially ineffective for treating ADHD when one looks at kids’ behavior over time – and that what’s missing (and what’s needed) is a much stronger focus on the psychosocial environment and not pharmaceuticals. 

There are two parts to this argument that I agree with and wish to expand on.

First, even though ADHD is believed to be highly heritable (based primarily on twin studies), this does not mean that kids with ADHD will not respond to changes in their environment – or that genetic or biological treatment is the only form of effective treatment. In fact, much of the most salient research on kids’ behavior problems conducted over the last decade has shown that “risk genes” are in fact highly responsive to the environment. Some studies have shown that psychosocial interventions work especially well for kids who have a “risk gene” (or more technically in these studies an allelic combination that confers the highest risk for a given disorder – such as two copies of the short arm of the serotonin transporter gene when examining depression). While this work has not been applied yet to ADHD it is becoming clear that genes and environment come together in specific and sometimes counterintuitive ways – and that kids who are at high risk genetically may also be highly likely to benefit from positive changes in their environment.

Second, perhaps the most important contribution of the essay is to point out that drug treatments for kids need to be evaluated over time and sometimes over years in order to understand how effective they really are. Through this lens I think it would be irresponsible to say that drug treatments alone produce the most beneficial developmental outcomes for kids with ADHD – modifying and structuring their environment is critically important.

While I appreciate the strong sentiment expressed in the essay, I do take a more balanced view in that I understand that some kids respond well to drugs such as Ritalin. But I see drug treatments for kids as a last step in a complex process that should start with, and focus heavily on, discovering what changes can be made in the psychosocial environment. This process ideally involves a partnership between clinicians, parents, and teachers. Once that is in place and executed over time, rational decisions can be made about the added value of considering drug treatment. In some cases introducing a drug into the mix may in fact make all the environmental changes that much more effective.

The bottom line is that it’s become necessary to champion the environment in an era of science and treatment that is infatuated with DNA and biology. Virtually all behavioral traits and disorders not only reflect genetic and environmental influences – much of the cutting edge research shows how the expression of genes are often dependent on the quality of the environment. And in the case of ADHD, it’s very important to reorient thinking about treatment to be sure that the essential and powerful role of environmental change is not forgotten.

Image of molecular ball and stick model via

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Nuture And Nature Both Shape Acting-Out Behaviors

Monday, May 23rd, 2011

Genetics gets more than it’s fair share of attention these days. This isn’t a bad thing — except that it seems like studies that focus on the environment don’t get the same play. So here’s one recent paper you should know about.

Drs. S. Alexandra Burt and colleagues studied acting-out behaviors in adoptive and biological adolescent sibling pairs. Siblings and their parents were videotaped while being asked to talk about two topics (one focused on the meaning of a Rorschach inkblot, the other on what to make of a moral dilemma). The idea was to see how teens behaved during conversations with their parents and their brother or sister, especially ones that could promote differences of opinion. Observers later viewed the videotapes and rated a number of acting-out behaviors for each adolescent, including things like getting angry, talking back, and whining.

The key thing about having adoptive and biological siblings is that it provided a method for inferring the role of genes and the role of environment. Here’s how it works. The researchers used a statistical method to see how similar each sibling pair was on the rated acting-out behaviors. In other words, if one sibling used a lot a acting-out behaviors, how likely was the other sibling to do the same?  If genetics was the only factor that influenced sibling similarity, then the adoptive siblings should, on average, not resemble each other very much (so that one sibling acting out a lot wouldn’t be associated with the other sibling doing the same). If genes did not play a role, then biological siblings should not be, on average, more similar in their acting-out behaviors than adoptive siblings.

Using this approach, Dr. Burt and colleagues found evidence that supported roles for both nature and nurture. Biological siblings were more similar than adoptive siblings, suggesting that genes do indeed make a contribution. However, adoptive siblings were also similar in their acting-out behaviors (at a statistically signifcant level), suggesting environmental influence independent of whatever role genetics may play.

These results are important for parents to consider because they remind us that although genes contribute to behavioral development, nature isn’t the only thing that matters. In my next post, I’ll discuss some of the environmental factors that may lead to acting-out behavior — and what parents can do about them.

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