Navigation Links
Study supports theory that rise in autism is related to changes in diagnosis

Research funded by the Wellcome Trust suggests that many children diagnosed with severe language disorders in the 1980s and 1990s would today be diagnosed as having autism. The research supports the theory that the rise in the number of cases of autism may be related to changes in how it is diagnosed.

Professor Dorothy Bishop, a Wellcome Trust Principal Research Fellow at the University of Oxford, led a study which revisited 38 adults, aged between 15-31, who had been diagnosed with having developmental language disorders as children rather than being autistic. Professor Bishop and colleagues looked at whether they now met current diagnostic criteria for autistic spectrum disorders, either through reports of their childhood behaviour or on the basis of their current behaviour. The results are published this month in the journal Developmental Medicine & Child Neurology(1).

Developmental language disorders, which include specific language impairment, are diagnosed when a child has unusual difficulty in his or her grasp of the spoken language, despite normal development in other areas. This may range from a child who has very limited ability to produce or understand spoken sentences, to one who does speak in long and complex utterances, but nevertheless has problem communicating effectively because of problems in conveying a point or grasping what others mean.

Autistic spectrum disorders, which include autism and Asperger syndrome, are developmental disorders affecting how a person communicates with and relates to other people and how they make sense of the world around them.

Participants in the study were drawn from a pool of children who had participated in a series of studies of developmental language disorder conducted during the period 1986 to 2003 and about whose conditions detailed information was known. All attended special schools or classes for children with language impairments, and would have been diagnosed by educational psychologists, paediatricians or speech therapists as having developmental language disorders and none had previously been diagnosed as autistic. However, when reassessed by Professor Bishop and colleagues using current criteria, around a quarter were identified as having autistic spectrum disorder.

In recent years, the criteria for diagnosing developmental language disorders and autism have changed. This has coincided with a marked rise in the rates of diagnosis of autism. According to the Special Needs and Autism Project(2), the figure until the 1990s was widely accepted as being about 5 people per 10,000; even using the narrowest definition of autism, this rose to almost 40 in 10,000 by 2006

There are two main hypotheses to explain this rise: the "autism epidemic" hypothesis and the "diagnostic substitution" hypothesis. Whilst the former says that the rise is genuine, the latter maintains that the true prevalence of the disorder is constant but that changes in diagnostic criteria mean that more children are being diagnosed as autistic. The latter theory is supported by a UK study(3) using the General Practice Research Database, which found that the rise in autism was mirrored by a decline in frequency of language disorders, and now by Professor Bishop's study.

"Our study shows pretty direct evidence to support the theory that changes in diagnosis may contribute towards the rise in autism," says Professor Bishop. "These were children that people were saying were not autistic in the 1980s, but when we talk to their parents now about what they were like as children, it's clear that they would be classified as autistic now.

"Criteria for diagnosing autism were much more stringent in the 1980s than nowadays and a child wouldn't be classed as autistic unless he or she was very severe. Now, children are being identified who have more subtle characteristics and who could in the past easily have been missed."

However, Professor Bishop cautions against using the results to suggest that the prevalence of autism is not genuinely rising.

"We can't say that genuine cases of autism are not on the increase as the numbers in our study are very small," she says. "However, this is the only study to date where direct evidence has been found of people who would have had a different diagnosis today than they were given fifteen or twenty years ago."


Contact: Craig Brierley
Wellcome Trust

Related medicine news :

1. New Study Shows the Use of MEDIHONEY(TM) Wound & Burn Dressing is Associated With Reduction in Wound Size
2. Study Shows the Personal Touch Is Key to Maintaining Weight Loss
3. Medical errors cost US $8.8B, result in 238,337 potentially preventable deaths: HealthGrades study
4. ASCRS to participate in and co-fund study on post-lasik quality of life with US FDA
5. New study finds adverse effects of estrogen replacement therapy are related to the dose
6. Geisinger study: Use of digital health records improve health of the elderly
7. Occupational therapists use Wii for Parkinsons study
8. Preliminary Data From Pitt County Memorial Hospital Study Show Benefit of Active Surveillance on Reducing MRSA VAP Rates in Surgical ICU
9. Animal Study Links Social Standing With Drug Use Risk
10. Study Shows Anger Has Its Uses
11. 1st US study -- gymnastics lands thousands in ER
Post Your Comments:
(Date:11/25/2015)... , ... November 25, 2015 , ... On November 10, ... States District Court of Connecticut on behalf of a home health care worker who ... current or former home health care workers employed by Humana, Inc., Humana at Home, ...
(Date:11/25/2015)... ... , ... On November 25, 2015, officials of Narconon Arrowhead , the ... of a new cutting edge recovery program that has been 50 years in the ... alcohol-addicted individuals with the purpose to free addicts from the symptoms and negative behaviors ...
(Date:11/25/2015)... ... , ... SCOTTSDALE, AZ) - Today, Dr. Todd C. ... and non-surgical treatments, announced the expansion of his private practice capabilities with the ... Highly trained and nationally recognized for his natural approach, Dr. Todd Hobgood serves ...
(Date:11/25/2015)... (PRWEB) , ... November 25, 2015 , ... Today, ... on our nation’s roadways has dropped below 10,000 for the first time since 2011. ... in 2013. , According to data released by the National Highway Traffic Safety Administration ...
(Date:11/25/2015)... , ... November 25, 2015 , ... ... of philanthropic seniors, is resulting in a way for homeless people to have ... Schaumburg have launched a new initiative whereby they are repurposing plastic bags into ...
Breaking Medicine News(10 mins):
(Date:11/24/2015)... , November 25, 2015 ... due to repeated failure of IVF cycles. After failure ... was totally dejected and had lost all hopes that she would be able ... Indian miracle child conceived after failure of over 15 ... abroad (UK) before they decided to take one last attempt with ...
(Date:11/24/2015)... SAN CARLOS, Calif. , Nov. 24, ... ), a leader in non-invasive genetic testing ... today announced that it will present at ... Conference in New York on Wednesday, December 2, 2015 at 1:00 p.m. ... discuss the Company,s financial results, business activities ...
(Date:11/24/2015)... /PRNewswire/ - ESSA Pharma Inc. ("ESSA" or the "Company") ... the first patient has been enrolled in ESSA,s Phase ... metastatic castration-resistant prostate cancer ("mCRPC"). the ... the United States and Canada.  ... trial, ESSA intends to demonstrate the safety, tolerability, maximum ...
Breaking Medicine Technology: