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Autism Prevalence: More Affected or More Detected?

29 Mar

Tom Insel, director of the U.S. National Institute of Mental Health and Chair of the Interagency Autism Coordinating Committee has published a blog article coinciding with the CDC announcement of 1 in 88 estimated prevalence.

As a government publication, I feel it is OK to copy it here in total, but you are encouraged to read it on the NIMH website: Autism Prevalence: More Affected or More Detected?

Autism is always surprising. Earlier today, the CDC released new numbers from their ongoing surveillance of autism prevalence, the Autism and Developmental Disability Monitoring (ADDM) Network. What was once considered a rare disorder is now reported as affecting 1 in 88 children, 1 in 54 boys. These new numbers, up 78 percent from 2002 and 23 percent from 2006, raise immediate questions. Are more children affected or more detected? Does the increase reflect a growing problem, or do these new numbers reflect an improvement in our ability to diagnose and serve those affected?

These new data do not answer these questions. The CDC surveillance project focuses on 8-year-olds identified in 2008; that is, children who were born in 2000. By definition, autism begins before age 3, so a focus on 8-year-olds should capture anyone who was identified and still has a diagnosis. The prevalence numbers are based on a standardized assessment of descriptions of behaviors culled from administrative or health records from select communities, not on standardized diagnostic interviews in the general population. The strength of this approach is its wide reach, allowing a comparison across 14 states. The CDC reports a four-fold variation across sites. These new results, as with those from other records-based surveillance systems, do not answer questions related to why the identified prevalence of autism has changed over time.

Other research suggests a complicated picture. A total population study of all 7–12-year-olds in a town in South Korea (more than 55,000 children) used standardized diagnostic instruments for children who screened positive and reported a prevalence of 2.64 percent.1 That is 1 in 38 children! There is no reason to expect that this prevalence is unique to this community. To be sure, two-thirds of these children had never received a diagnosis of autism spectrum disorder (ASD), meaning that the identified prevalence was closer to 1 percent or one in 100, roughly the same prevalence reported in the United States. From this perspective, the increase reported by the CDC might mean we are better at detecting children who meet criteria for ASD, but potentially we still are only halfway to the actual prevalence in the general population. Indeed, the biggest increase in the CDC surveillance report was in Hispanic and African American children, groups which previously had low rates of detection.

But can we be certain that more children are not affected? Data from the Developmental Disability Services registry in California demonstrates a 12-fold increase in the number of children receiving services for autism over the past 20 years, with a continuing rise recently. But these data, while dramatic, cannot rule out increased use of the diagnosis. Bearman and colleagues who have studied the California trends suggest that only about 26 percent of this increase can be explained by diagnostic substitution, especially for the most severe cases — children with intellectual deficits — which may not have been identified as autism in an earlier era. Another fraction can be attributed to better ascertainment or detection especially for children at the less severe end of the spectrum. Together these factors explain only a part of the linear increase observed in the California registry. In the absence of other explanations they and others suggest that a real increase is quite likely.2, 3, 4

Which makes a recent report from England especially surprising. In a careful epidemiological study based on a national sample (n = 7,461 adults) from 2007, Brugha and colleagues did careful diagnostic assessments based on standardized interviews. They found that familiar rate of about 1 percent in adults across the entire age range without a significant reduction in the older part of the sample as one would expect if the prevalence had increased in recent years.5

This takes us back to the central question: has the number of children with ASD increased or not? Total population epidemiological studies suggest much or all of the increase is due to better and wider detection. Studies of administrative and services data suggest that better detection cannot fully explain the profound and continuing increase. Are we seeing more affected or more detected? The question is vitally important, but there is not one, simple answer just as autism is not a single, simple disorder.

If there is an increase in the number affected, then we need to find the causal factors to bend the curve. Analogous increases in food allergies, asthma, and Type 1 diabetes have provoked an aggressive search for environmental causes. If the number of children with ASD has not changed, but we are diagnosing and serving 12-fold more of them over the past two decades, then we need to focus on better diagnosis and treatments rather than looking for new environmental factors driving the precipitous increase.

Science can resolve this dilemma, but the methods to examine this question as well as the answers will be complex. While it is never possible to go back in time, longitudinal population based studies and even careful retrospective studies can determine if more children are affected and if the nature of the disorder is changing over time. The changes in prevalence of other developmental disorders, measured with biomarkers (Type 1 diabetes) or emergency room visits (food allergies), appear to be true increases in the number of children affected. As diagnostic changes and ascertainment fail to explain the majority of the increase in autism prevalence, it seems prudent to assume that there are indeed more children affected and continue an aggressive search for causes while striving to improve detection, treatments, and services. Our working assumption is that there are both more children affected and more detected.

References

1Kim YS, Leventhal BL, Koh YJ, Fombonne E, Laska E, Lim EC, Cheon KA, Kim SJ, Kim YK, Lee H, Song DH, Grinker RR. Prevalence of autism spectrum disorders in a total population sample. Am J Psychiatry. 2011 Sep;168(9):904-12. Epub 2011 May 9. PubMed PMID: 21558103.
2King M, Bearman P. Diagnostic change and the increased prevalence of autism. Int J Epidemiol. 2009 Oct;38(5):1224-34. Epub 2009 Sep 7. PubMed PMID: 19737791; PubMed Central PMCID: PMC2800781.
3Keyes KM, Susser E, Cheslack-Postava K, Fountain C, Liu K, Bearman PS. Cohort effects explain the increase in autism diagnosis among children born from 1992 to 2003 in California. Int J Epidemiol. 2011 Dec 7. [Epub ahead of print] PubMed PMID: 22253308.
4Bresnahan M, Li G, Susser E. Hidden in plain sight. Int J Epidemiol. 2009 Oct;38(5):1172-4. PubMed PMID: 19797336.
5Brugha TS, McManus S, Bankart J, Scott F, Purdon S, Smith J, Bebbington P, Jenkins R, Meltzer H. Epidemiology of autism spectrum disorders in adults in the community in England. Arch Gen Psychiatry. 2011 May;68(5):459-65. PubMed PMID: 21536975.

Vaccine-autism groups jump embargo on CDC prevalence

28 Mar

The CDC will soon release new autism prevalence estimates. This much has been discussed online for some time since Disability Scoop published CDC Set To Release New Autism Numbers on March 9.

The “Canary Party” has put out a couple of press releases. One “New CDC Autism Numbers Coming Soon; Rate Increase to Over 1 in 100 Expected by The Canary Party ” and another (which appears to be submitted twice) “The Canary Party Expects CDC to Announce New Autism Rate of 1 in 88, and Believes CDC Likely to Declare “No Public Health Emergency” and “No Epidemic”” The Canary Party is an offshoot of the autism-is-caused-by vaccine organizations like SafeMinds (whose Mark Blaxill is quoted in the press releases).

Also, A-Champ sent out an email alert along similar lines.

These groups appear to be vying for media attention. By getting their press releases out before the embargo is lifted, they might be in a position to get media organizations to contact them for quotes.

It is not the most ethical way to obtain media attention. It also isn’t really that effective. One can tell this because, it didn’t work last time. Yes, multiple groups broke the embargo for the 1% prevalence estimate which came out in the journal Pediatrics in 2009. This was discussed at length here at Left Brain/Right Brain in Autism rate of 1 percent, and the embargo that wasn’t. The media discussed not the talking points of these groups, but the broken embargo. See When News Breaks On Autism, Who Gets It Out First? and Autism news raises question: When is an embargo not an embargo?

Interestingly, the Canary Party press release doesn’t mention mercury, thimerosal or vaccines. Just “The only plausible explanation for these rapid increases is a change in the environment affecting millions of American children” Which ignores a great deal of work published in the last 10 years, especially that of Prof. Peter Bearman’s group at Columbia which has quantified some of the social factors behind the increases observed.

For those who haven’t heard of the “Canary Party”, you are not alone. It is a small (under 5,000 facebook “likes”. Compare that to over 315,000 for the Democratic Party, or over 1 million likes for Autism Speaks).

Autism News Beat has also discussed the broken embargo in Embargo? What embargo?

note: I edited this article after publishing to complete an incomplete sentence in the first paragraph.

Why the next CDC autism rates spells bad news for the mercury hypothesis

22 Mar

A recent article on Disability Scoop discussed an upcoming CDC autism report. The MMWR’s(Morbidity and Mortality Weekly Reports) from the CDC have been one of the standards for autism prevalence for years. Each CDC prevalence estimate is calculated for a group of 8 year olds born in a certain year. For example, the last estimate was “Prevalence of Autism Spectrum Disorders — Autism and Developmental Disabilities Monitoring Network, United States, 2006” for children born in 1998.

Every time a new CDC autism MMWR has come out, the prevalence estimates are higher. Every timer there are groups that point to the rising number of vaccines and mercury exposure from those vaccines. People point out that there is a correlation between mercury exposure (thimerosal) and the autism rates. The MMWR’s so far have been all for children born in the 1990’s, a period when the number of vaccines and the thimerosal exposure from those vaccines was increasing.

Here are the autism prevalence estimates from recent CDC reports:

2006 (birth year 1998) 9 per 1000
2004 (birth year 1996) 8 per 1000
2002 (birth year 1994) 6.6 per 1000
2000 (birth year 1992) 6.7 per 1000

Following this trend, the next report will be for children born in 2000, age 8 in 2008. From the perspective of testing the vaccine hypothesis, in particular the mercury/thimerosal hypothesis, this is the start of a new era. In 1999 the AAP recommended that thimerosal be removed from vaccines. By 2001, all infant vaccines with the exception of influenza were produced only in thimerosal-free versions. This means that children born in 2000, the cohort the CDC will likely report upon, received, on average, a lower exposure to thimersal than the previous groups.

If the mercury hypothesis were correct (and there already a great deal of evidence to say that it is *not* correct) the autism rate should go down. At the very least, it should stay the same as the group before–about 0.9%.

Of course we will hear claims like “but not all the thimerosal containing vaccines were gone for this group” and “but what about the influenza vaccine?” and more obvious excuses in case (at it seems likely) the prevalence goes up again.

All of these avoid the fact that the average thimerosal exposure will be much lower for this group than the previous (1998 birth year) group. The excuses amount to…well…how about a visual?

With thanks to Reuters for the image I am using.

Yes, goal posts will move. Nice idea putting them on wheels. Could save a lot of effort, but those promoting the mercury idea are already used to moving goalposts.

And what if the CDC also reports on birth year 2002 (they have reported two birth cohorts at the same time in the past)? Those goalposts might to have to move quite a bit.

Now consider a different perspective. Consider that each CDC report has been an undercount. They don’t do a “whole population” survey like was done in Korea recently. They don’t test all children, they rely upon records already in existance. The last CDC report found that about 23% of the children identified as autistic in the study did not have a diagnosis before the study. Clearly the United States has not been identifying all the autistics in the population. Given this, the rising autism prevalence estimates (and, yes, they are *estimates*) could be seen as an accomplishment. This is a position put forth by Prof. Richard Grinker. The rising prevalence estimates reflect a the U.S. getting better at identifying the autistic students in our schools.

CDC Set To Release New Autism Numbers

16 Mar

Disability Scoop has an article: CDC Set To Release New Autism Numbers. This was posted last week, and it starts:

The Centers for Disease Control and Prevention are expected to unveil a new autism prevalence estimate as early as this month.

The agency currently says that 1 in 110 children have autism, a figure first released in late 2009. Now, less than three years later, the CDC is set for an update.

I had heard rumors that the next prevalence estimate would be much higher. Not higher than the Korean prevalence numbers, but a significant jump. But–I heard these rumors together with the prediction that the estimate would come out last year. So, rumors are worth what you pay for them.

Autism recurrence in half siblings: strong support for genetic mechanisms of transmission in ASD

5 Mar

Autism recurrence in half siblings: strong support for genetic mechanisms of transmission in ASD comes out of Dan Geschwind’s group at UCLA. They used the Interactive Autism Network database. Here is the abstract:

Current estimates of the heritability of autism spectrum disorders (ASD) derived from existing clinical twin studies1, 2, 3, 4 are potentially confounded by a number of factors, including low sample size, inconsistency in case definition and the role of de novo mutation (currently estimated to contribute to some 20% of cases), and the possibility that heritable causes of ASD in a twin could result in environmentally engendered affectation of a non-identical co-twin in utero, especially if mediated by humoral or immune mechanisms. To minimize these confounds, we compared autism recurrence in half siblings versus that in full siblings, using data (6 June 2011) from over five thousand families enrolled in the Interactive Autism Network (IAN), a national volunteer register for ASD, detailed characteristics of which have been previously described by our group. Recurrence rate among full siblings was observed to be approximately twice that among half siblings, providing strong evidence of genetic transmission of ASD.

The recurrence risk is the chance that a sibling has autism if another sibling does. The authors found the recurrence risk to be twice as high for full siblings, which is consistent with a primarily genetic model of autism risk.

This follows on a number of recent twin studies (here, here and here) have shown a lower concordance than previously estimated and the baby siblings study which showed a 19% recurrence risk for autism.

I wonder at how many half-siblings there are in the cohort. A small subpopulation could mean large error bars.

Differences in White Matter Fiber Tract Development Present From 6 to 24 Months in Infants With Autism

23 Feb

If you watch for autism related news stories you likely have seen multiple stories on a paper out Friday in the American Journal of Psychiatry: Differences in White Matter Fiber Tract Development Present From 6 to 24 Months in Infants With Autism (full paper available online). The researchers studied brain structure in children and compared those who went on to be diagnosed with autism to those who did not. They found differences in white matter between the two groups. In particular fiber tracks were different.

Here’s figure 1 (click to enlarge) from the paper to give you an idea of what they mean by fiber tracks. Check the brain cartoons on the right. Then check the actual data in the graphs. These are “significantly different” trajectories for these measurements. They are not clear differences that could lead to a diagnostic tool.

Here is the abstract:

Objective:

Evidence from prospective studies of high-risk infants suggests that early symptoms of autism usually emerge late in the first or early in the second year of life after a period of relatively typical development. The authors prospectively examined white matter fiber tract organization from 6 to 24 months in high-risk infants who developed autism spectrum disorders (ASDs) by 24 months.
Method:

The participants were 92 high-risk infant siblings from an ongoing imaging study of autism. All participants had diffusion tensor imaging at 6 months and behavioral assessments at 24 months; a majority contributed additional imaging data at 12 and/or 24 months. At 24 months, 28 infants met criteria for ASDs and 64 infants did not. Microstructural properties of white matter fiber tracts reported to be associated with ASDs or related behaviors were characterized by fractional anisotropy and radial and axial diffusivity.
Results:

The fractional anisotropy trajectories for 12 of 15 fiber tracts differed significantly between the infants who developed ASDs and those who did not. Development for most fiber tracts in the infants with ASDs was characterized by higher fractional anisotropy values at 6 months followed by slower change over time relative to infants without ASDs. Thus, by 24 months of age, those with ASDs had lower values.
Conclusions:

These results suggest that aberrant development of white matter pathways may precede the manifestation of autistic symptoms in the first year of life. Longitudinal data are critical to characterizing the dynamic age-related brain and behavior changes underlying this neurodevelopmental disorder.

If the idea of differences in fiber tracks seems somewhat famiiliar, last year Eric Courchesne at UCSD reported at IMFAR about
Abnormally Accelerated Development of Higher-Order Long-Distance Cerebral Tracts In ASD Infants and Toddlers. The paper was highlighted at the IMFAR press conference (and discussedhere at Left Brain/Right Brain.

At the press conference David Amaral mentioned similar work at the IMFAR press conference last year.

At 51:20 in the video above, Prof. Amaral speaks on the work that precocious brain growth at 4-6 months of age in infants and is most prominently present in children with regression.

“..despite the fact that the regression, the behavioral regression, takes place at 18 months or 24 months, the brain changes actually started taking place at 4 to 6 months. So it actually casts a doubt on the idea that a vaccine, the MMR vaccine for example that’s taken at 12 to 18 months, would be actually the precipitating factor because things were starting much much earlier than that.”

The talk that Prof. Amaral was speaking about was Total Cerebral Volume Is Associated with Onset Status In Preschool Age Children with Autism.

C. W. Nordahl1, A. Lee1, M. D. Shen1, T. J. Simon1, S. J. Rogers1, S. Ozonoff2 and D. G. Amaral1, (1)Psychiatry and Behavioral Sciences, UC Davis M.I.N.D. Institute, Sacramento, CA, (2)Psychiatry and Behavioral Sciences, M.I.N.D. Institute, UC Davis, Sacramento, CA
Background: Autism is a heterogeneous disorder, and multiple behavioral and biological phenotypes likely exist. One well-characterized behavioral phenotype is onset status. While some children with autism exhibit symptoms very early in life, others experience a regression or loss of previously acquired skills. There is currently very little known about the neural substrates associated with these two different behavioral trajectories in autism.

Objectives: We examined the relationship between total brain volume and onset status in a large sample of 2-4 year old children with autism spectrum disorder (ASD) (n = 48, early onset, n = 58, regression) and a comparison group of age-matched typically developing children (TD) (n = 55).

Methods: Diagnoses and autism severity were based on ADOS and ADI-R scores and clinical judgment by trained, experienced psychologists. Developmental quotients (DQ), verbal quotients (VQ) and nonverbal quotients (NVQ) were based on the Mullen Scales. Onset status was categorized based on parent reports from related ADI-R questions. Total cerebral volume was compared between autism onset groups as well as relative to age-matched typically developing controls. Autism severity and DQ were also evaluated in relation to brain volume and onset status.

Results: Children who exhibited regression had significantly larger total brain volumes than children with early onset autism (p = .004). Total brain volume in the early onset ASD group did not differ from the TD group, whereas total brain volume was significantly larger in the children with regression. Moreover, children with regression had significantly lower VQ (p = .03) and higher (i.e. more severe) ADOS social and communication scores (p = .02). Total brain enlargement remained significant even after controlling for these variables. There were no significant correlations between total brain volume and VQ or ADOS scores.

Conclusions: Total brain enlargement has been reported in children with autism under the age of five. However, behavioral associations with abnormal brain enlargement have not been fully explored. Our findings suggest that abnormal brain enlargement in autism is associated with a parent-reported regressive pattern of onset and more severe symptoms involving both developmental impairment and ASD severity.

The idea that autism, even regressive autism, has signs as early as 6 months is challenging to some groups on two levels. First the idea that autism involves physical differences in the brain. Second that these differences are present well before regression, or well before vaccines which are sometimes proposed as precipitating events.

The study itself has limitations, one being generalizability. It makes a lot of sense to monitor siblings of autistics since the recurrence risk is high and the chances of collecting data on autistics is higher than in the general populaiton. However, this leaves us with the question: are the types of autism found in siblings (familial autism) representative of all forms of autism?

Apply for IMFAR Travel Grant from the Autism Science Foundation

23 Feb

Are you interested in attending IMFAR (the International Meeting for Autism Research)? The 2012 conference will be held in Toronto, May 17 – May 19. I attended last year in San Diego with the assistance of the Autism Science Foundation (ASF) through a travel grant. If it was possible, I would go this year as well even without the grant.

Applications are open for this year’s ASF travel grants but the deadline (February 29) is coming very quickly. If you are thinking of applying, now is the time.


Here is the announcement from the Autism Science Foundation. I’ll highlight this section:

Applicants should send a letter to grants@autismsciencefoundation.org describing why they want to attend IMFAR and explaining how they would share what they learned with the broader autism community.

Below is the announcement in full:

We are now accepting applications for travel grants to send a limited number of parents of children with autism, individuals with autism, special education teachers, and other stakeholders to attend the International Meeting for Autism Research (IMFAR). This year the conference will be held in Toronto, Canada from May 17-19.

The awards cover up to $1,000 of expenses to be used for registration, travel, accommodations, meals and other directly related expenses, including childcare or special accommodations to enable individuals with autism to participate. Grantees are responsible for obtaining international travel documents.

Applications must be received by February 29, 2012.

Grant Requirements:

Grantees must submit the original receipts for reimbursement and are expected to submit completed travel expense forms within 15 days of return from IMFAR.
Grantees are asked to participate in ASF related activities at IMFAR including a group photo and social media promotion. Full details will be shared closer to the event.
After attending the conference, grantees are asked to share what they learned in their own communities to further spread the knowledge gained within 6 months of attending IMFAR. Grantees are asked to send a short write-up plus photos or a video of their activity for use by ASF.

To apply:

Open to autism stakeholders: individuals with autism, parents of children with autism, special education teachers, graduate and undergraduate students, journalists, and others.
Grants are awarded to US residents only, over 18 years of age.
Applicants should send a letter to grants@autismsciencefoundation.org describing why they want to attend IMFAR and explaining how they would share what they learned with the broader autism community.
Letters should be sent as Microsoft Word attachments of no more than 2 pages, 12-point type, “Arial” font, with standard margins.
In the email subject line please write: IMFAR Grant.
Letters must be received by February 29, 2012.

Recipients will be announced in late March.

Severe Influenza Among Children and Young Adults with Neurologic and Neurodevelopmental Conditions — Ohio, 2011

17 Feb

Children with neurologic and neurodevelopmental conditions are at increased risk for severe outcomes from influenza, including death. Those aren’t my words. They are the first sentence in a new report by the CDC: Severe Influenza Among Children and Young Adults with Neurologic and Neurodevelopmental Conditions — Ohio, 2011.

Individuals with developmental disabilities are at a higher risk of harm or death from infectious diseases. They are also often more difficult to diagnose due to many factors including difficulties with communication.

The residents included a high percentage of individuals with great challenges. For example, of those with severe infections, nine had “do not resuscitate” orders (the reasons for this is not given).

All 13 residents with severe influenza had severe to profound neurologic and neurodevelopmental disabilities, including physical limitations (e.g., scoliosis, hemiplegia or quadriplegia, or cerebral palsy) (Table 1), and nine had “do not resuscitate” orders.

The story from this Ohio facility is bad on many fronts. An outbreak of influenza swept through the facility. 130 residents total. 76 residents had acute onset of respiratory illness. 13 were severely ill. 10 were hospitalized, and seven died.

All of those severely ill had the influenza vaccine. However, during the investigation it was found that the refrigerator that stored the vaccines was 27 degrees F. If the same temperature was in effect while the vaccines were stored, the low temperature could have inactivated the vaccine.

In other words, these individuals were given vaccines but they could have been rendered useless by the storage conditions.

Here is the abstract:

Children with neurologic and neurodevelopmental conditions are at increased risk for severe outcomes from influenza, including death. In April 2011, the Ohio Department of Health and CDC investigated an influenza outbreak that began in February 2011 in a residential facility for 130 children and young adults with neurologic and neurodevelopmental conditions. This report summarizes the characteristics and clinical courses of 13 severely ill residents with suspected or confirmed influenza; 10 were hospitalized, and seven died. Diagnosis is challenging in this population, and clinicians should consider influenza in patients with neurologic and neurodevelopmental conditions who have respiratory illness or a decline in baseline medical status when influenza is circulating in the community. Prompt testing, early and aggressive antiviral treatment, and antiviral chemoprophylaxis are important for these patients. When influenza is suspected, antiviral treatment should be given as soon as possible after symptom onset, ideally within 48 hours. Treatment should not wait for laboratory confirmation of influenza. During outbreaks, antiviral chemoprophylaxis should be provided to all residents of institutional facilities (e.g., nursing homes and long-term- care facilities), regardless of vaccination status. Residential facilities for patients with neurologic and neurodevelopmental conditions are encouraged to vaccinate all eligible residents and staff members against influenza.

The story notes the relatively low efficacy of the influenza vaccine (about 60%). If the vaccines were compromised by low temperature storage, 60% efficacy could have saved 4 of the seven people. So called “vaccine safety” groups should be calling for more effective vaccines, not downplaying the need for vaccines using the 60% figure.

What are the take-away messages from this? For one, influenza *is* a serious disease. Especially to many in the disability community.

Yale Daily News: Redefinition of autism sparks concerns

3 Feb

The proposed changes to the way autism is diagnosed with the DSM 5 has sparked a lot of discussion in the online autism communities and elsewhere. A surge in the discussion came in response to a New York Times article New Definition of Autism Will Exclude Many, Study Suggests, in which the Times discussed preliminary results of a study by Prof. Volkmar of Yale.

The Times put the emphasis on reducing the “autism surge”, quoting Prof. Volkmar as saying “We would nip it in the bud”:

The new analysis, presented Thursday at a meeting of the Icelandic Medical Association, opens a debate about just how many people the proposed diagnosis would affect.

The changes would narrow the diagnosis so much that it could effectively end the autism surge, said Dr. Fred R. Volkmar, director of the Child Study Center at the Yale School of Medicine and an author of the new analysis of the proposal. “We would nip it in the bud.”

The Yale Daily News has an article “Redefinition of autism sparks concerns” where they sought more dicussion from Prof. Volkmar:

“I think [the proposed revision] is a mistake,” Volkmar said. “It changes people’s eligibility for key services, and a lot of people expressed concern.”

He said the change would not only affect autistic patients’ access to medication and medical services, but also impact their eligibility for special schools. Volkmar also questioned the scientific validity of the decision.

You can read more about this story on the Yale Daily News website.

Estimating the Prevalence of Autism Spectrum Conditions in Adults: Extending the 2007 Adult Psychiatric Morbidity Survey

1 Feb

You may recall that a couple of years ago a study came out looking at the prevalence of autism in adults in the United Kingdom. They found a prevalence of about 1%, the same as in children.

There’s now a follow up study. The press release is below. The study can be found here. I hope to have the time to go into this in more detail in the next couple of days.

University of Leicester researchers lead on new autism study published today
Britain’s first adult autism survey reveals previously ‘invisible’ group with autism

New research on autism in adults has shown that adults with a more severe learning disability have a greater likelihood of having autism.

This group, mostly living in private households, was previously ‘invisible’ in estimates of autism.

Dr Terry Brugha, Professor of Psychiatry at the University of Leicester, led research on behalf of the University for the report Estimating the Prevalence of Autism Spectrum Conditions in Adults: Extending the 2007 Adult Psychiatric Morbidity Survey, which has today been published by the NHS Information Centre.

The report involved a survey of adults from learning disability registers in Leicestershire, Lambeth and Sheffield between August 2010 and April 2011.

Today’s report presents findings from a new study based on a sample of people with learning disabilities living in private households and communal care establishments. The findings are combined with information from the Adult Psychiatric Morbidity Survey (APMS) 2007, previously published by the NHS Information Centre, which included research on autism also led by Dr Brugha.

Dr Brugha, also a consultant psychiatrist working in the NHS with the Leicestershire Partnership NHS Trust, said: “We were surprised by how many adults with moderate to profound learning disability had autism because previous estimates pointed to lower rates in this group. Because they form a very small part of the adult population, when we added these new findings to the rate we had previously found in adults living in private households, and able to take part in our national survey in 2007, the overall percentage of adults in England with autism did not increase significantly over our 2007 estimate of 1%.”

“Our finding that about 60% of men with profound learning disabilities and 43% of women with profound learning disabilities have autism has never been shown previously. It may also seem surprising how many live at home with parents or carers who provide 24 hour care and shoulder a considerable burden: 42% of men and 29% of women with severe learning disabilities living with family members and in other private households have autism. Taken together with the 2007 survey findings this means that most adults with autism live in private households, and before these two surveys they remained largely invisible”.

Dr Brugha added “This new information will be of particular importance for those who plan and provide services to support those with learning disabilities. In March 2010, the Government published a national strategy for autism and guidance for the condition, with the view to improving the quality of services provided to adults with autism in England. Such improvements can only be achieved if the number of people with recognised and unrecognised autism is quantified. The strategy gave special emphasis to the need to train staff who have responsibility for identifying people with autism and their care. It will be vital to repeat such studies in future years in order to make sure that the national strategy is working effectively.”

Sally-Ann Cooper, Professor of Learning Disabilities at the University of Glasgow, who also contributed to the latest study commented: “Until now routine statistics have not been gathered on the numbers of people with learning disabilities who also have autism leaving this as a hidden problem. Our study clearly shows that the more severe to profound an adult’s learning disability is, the more likely they will be found to have autism if actually assessed.”

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