The prevalence of ASD is relatively low in both rural and urban India, according to a recent meta-analysis of published studies.
The study, titled ‘Prevalence of Autism Spectrum Disorder in Indian Children: A Systematic Review and Meta-Analysis’, is a review of four studies that included diagnostic screening of 130,599 children belonging to the southern Indian site of Kerala, Kolkata from eastern India and Himachal Pradesh, northern India.
The analysis found that ASD prevalence in rural settings was 0.11% in the age range of 1–18 years, as per the data provided by one of the four included studies. The other three studies found the rates to be slightly lower in the urban population at 0.09% in the age range of 0–15 years.
The pooled estimate of autism varied from the rural to the urban population from 14/10,000 to 12/10,000. These figures are relatively lower than those reported from the US and UK, notes the authors, who belong to the Indian Council of Medical Research Advanced Centre for Evidence Based Child Health, Department of Pediatrics, Advanced Pediatrics Centre, Postgraduate Institute of Medical Education and Research, Chandigarh.
In the UK, the pooled estimated prevalence of ASD was 14.6 per 1,000 (1 in 68) children aged 8 years and the weighted prevalence of ASD in adults was 9.8/1,000.
All the four studies included in the systematic review have used a varied spectrum of diagnostic tools for the screening of autism. Some studies have used a single diagnostic tool and others have used more than one tool to detect autism.
Two of the studies used the Diagnostic and Statistical Manual of Mental Disorders – Fourth edition (DSM-IV) for the clinical evaluation of screened children. DSM is published by the American Psychiatric Association which serves as the principal authority for psychiatric diagnoses in the US. While one study used the Indian Scale for Assessment of Autism (ISAA), a locally developed standardised tool useful for the diagnosis of ASD, which includes screening questions pertaining to social relationship and reciprocity, emotional responsiveness, speech, language and communication, behavioural patterns, and has sensory and cognitive components.
There is a need for such large population-based epidemiological surveys, which will be helpful in estimating the exact burden of ASD in India, note the authors of the study published in the Neurology India journal March 2020.
Currently, no published data is available on the prevalence of autism in adults.
Socio-cultural factors play a major role in early identification, diagnosis and management of ASD.