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School survey in India reveals low autism prevalence

by  /  12 July 2017
School figures: Scientists screened children at this childcare center in Kolkata for features of autism.

This article has been updated to include comments from two researchers not involved in the work.

Roughly 23 of every 10,000 children in India have autism, according to the first rigorous estimate of the country’s autism prevalence1.

This rate, about 0.23 percent, is far less than the 1.47 percent in the United States.

“The received wisdom is one percent of the world’s population has autism,” says lead researcher Bhismadev Chakrabarti, research director of the Centre for Autism at the University of Reading in the United Kingdom. The new finding, he says, challenges that notion: “We should not think that the one percent figure is really universal and has no cultural variability.”

Even though autism prevalence is low in India, the condition still represents a significant problem, he says. “When we are talking about 0.23 percent of 1.2 billion people, that’s a large number.”

Chakrabarti and his colleagues looked at autism features in more than 11,000 children in Kolkata, a metropolis in eastern India. They relied on a series of questionnaires completed by parents and teachers. They then clinically assessed a small proportion of the children, and found six who meet the criteria for autism. The findings were published 25 May in Autism Research.

“It’s a small sample, but it’s a very well-done study,” says Eric Fombonne, professor of psychiatry at Oregon Health and Science University in Portland, who was not involved in the work. “It’s the first benchmark for this country.”

The figure could be an underestimate, however, because nearly 20 percent of children in the city do not attend school. Autism prevalence among those children could be higher, Chakrabarti says, because children with severe autism may be less likely to go to school.

Prevalence puzzle:

Estimates of autism prevalence for many countries have relied on medical records. But when Chakrabarti’s team contacted 15 hospitals and clinics in India, they found only 1 that recorded autism diagnoses. So they decided to screen and diagnose children themselves.

The team did so in three stages, modeling their school-based screening on a 2009 study in the United Kingdom2. They first translated the questionnaires into Bengali and Hindi, the predominant languages spoken in Kolkata, and validated them for use in India.

In the first stage of the study, teachers at 27 mainstream schools and 1 special-needs school filled out a 12-item questionnaire. Altogether, they assessed the social skills and communication abilities of 11,849 students between 3 and 8 years of age.

The researchers also sent copies of the screen, called the Social Communication Disorder Checklist, home with all of the children. Parents of 5,947 children completed the assessment. Based on this, 1,247 children scored as having social and communication difficulties, core features of autism.

The researchers asked these parents to fill out a 40-item survey of autism traits called the Social Communication Questionnaire. They received completed surveys from 882 parents. Among these, 124 children scored above the cutoff for autism risk.

Manageable pool:

Chakrabarti’s team invited the 124 children for a full diagnostic evaluation. Of the 116 children who underwent the exam, 6 meet the diagnostic criteria for autism.

“It’s a very clever way to do the screening phase,” Fombonne says. “First they use a broad screen that is easy to use, then they narrow down on more autism-specific symptoms and end up with a smaller, more manageable pool of children that they assess more intensively.”

All six of the children diagnosed are boys. “That’s remarkable,” Fombonne says. Chakrabarti says the screening tools his team used may miss autism features in girls.

The researchers then extrapolated their findings from these 28 schools to all school-age children in Kolkata. (They used the teachers’ responses from the first phase of the study to account for the children whose parents did not participate.) They arrived at a prevalence of 0.23 percent.

“This is the first systematic, well-conducted study in India that has looked at such large numbers of children in schools,” says Koyeli Sengupta, director of Autism Intervention Services at the Ummeed Child Development Center in Mumbai, who was not involved in the study. Sengupta says it is likely to encourage others in India to do similar work.

Still, the estimate of prevalence should be considered preliminary, says Prathibha Karanth, director of the Communication DEALL Trust, an early-intervention program for children with autism in Bangalore. The children in the study were about 6 years old on average, but “children of this age with more severe disorders are highly unlikely to be enrolled in these schools,” says Karanth, who was not involved in the study. Future work should include younger children and use broader criteria to identify children with autism, she says.

Chakrabarti’s team is developing an app to screen for autism features in children. The app would also capture the children’s behaviors. Chakrabarti says nonspecialist workers could use the app to screen children in India for autism in their homes.

  1. Rudra A. et al. Autism Res. Epub ahead of print (2017) PubMed
  2. Baron-Cohen S. et al. Br. J. Psychiatry 194, 500-509 (2009) PubMed

4 responses to “School survey in India reveals low autism prevalence”

  1. Seth Bittker says:

    This is an important finding. What people ought to be asking next is why is it that a rigorous ASD screen in India finds 1 in 400 have ASD, while a rigorous ASD screen in the USA or UK finds that 1 in 100 have ASD? I believe the traditional view of this discrepancy is that cases are missed in societies where screening and medical care are less widely available. An alternative view is that some environmental factors are significantly increasing ASD risk in some societies.

    • One and only Dada says:

      First of all, surveying in schools in itself a wrong measure, because in India almost all mainstream schools do not cater to autistic children at all. So why did he choose schools as a research base, the researcher only knows. Maximum children end up in special schools. Autism is still a thing to hide in this country. There is very little help from government and all effort and cost is borne by the hapless parents. Secondly in India , Kolkata is least aware about Autism than other major cities. The available service is also very less. For getting the true numbers, one must ask the preschools as well as the paeditricians, the national institutes for disability, apex NGO’s like Action for Autism e.t.c. This research does not at all look conclusive.

      • Claire Cameron says:

        From the lead researcher Bhismadev Chakrabarti:

        “We agree that it would be very informative to measure the prevalence rate of autism from outpatient department of child psychiatry units/ paediatric clinics/ special schools.

        Our decision to go with schools was based on four factors:
        1) All but one of the outpatient departments that we contacted did not maintain systematic patient records to provide this data. A second problem with a OPD/clinic-based strategy to obtain the numbers is the determination of the catchment area. Given the dearth of specialist clinics, people often travel from faraway places to get ASD diagnoses in specialist clinics. It therefore becomes difficult to determine the true denominator to use in calculating the prevalence ratio.
        2) The schools based strategy provides a somewhat tighter (though not perfect) boundary on the catchment area. In our study we included government, private, and NGO-run schools from 3 boroughs, as well as a special school that fell within that area (please see table 1 in the paper).
        3) We have collaborated closely with the apex NGO suggested by the commentator, Action for Autism (please see Rudra et al., 2014, Autism Research) for this research. Unfortunately there is no systematic nationwide estimate of the numbers of people with ASD held by the central bodies, to the best of our knowledge.
        4) While OPD/clinic based surveys are likely to pick up on the more severe end of the spectrum, many of the less severely affected children might remain un-noticed, and often face difficulties when placed in mainstream schools. Our school-based strategy allowed for the detection of all such cases, as it was not dependent on finding children with an existing clinical diagnosis.

        We acknowledge the point that our estimate is likely to represent the lower bound since many of the severely affected children with ASD are unlikely to attend schools. However, we would like to believe that this study is a first step toward large scale population-based studies.”

        • One and only Dada says:

          1. I did not get the first point because though people travel from faraway places to specialist clinics, all have to enter their address, so by sorting on their address , one could have got a fair idea about the actual locatio of the families coming for treatment.
          2. The number of schools involved in this survey is very less to make a sweeping statement such as “School survey in India reveals low autism prevalence” rather it would have been better to say that “School survey in India reveals low autism prevalence as most of the autistic children are out of the school system”. Please pardon me, but getting data from only one special school does not seem rigorous enough.
          3. “Unfortunately there is no systematic nationwide estimate of the numbers of people with ASD held by the central bodies” – This is the main problem as Autism is India is still shunned and in surveys people might not give the correct data.
          4. Let us not distinguish between severely affected and not so severely affected with regard to schooling as getting school exposure is a right for everybody. One of the major pain areas of being born with Autism in India is the indirect sentiment that if you have a mental disability, then school is not for you as you do not have the mental ability to study. Fact is that Autistic children can progress to a remarkable degree if proper resources and intention is there but that is sadly lacking in India and specially in West Bengal. There is very little awareness.
          Lastly it is very good that such sort of surveys are being done, but request is to widen the net of survey so that the actual picture comes out.
          Making statements like “Roughly 23 of every 10,000 children in India have autism, according to the first rigorous estimate of the country’s autism prevalence” actually brings down the morale of parents who are fighting a lone battle for bringing in more government help. Hope you understand!

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