As autism awareness continues to grow globally, a burgeoning research literature is emerging from countries in which previous studies and reports of ASD were limited. A review of literature within a specific country or region is an excellent way to synthesize often disjointed areas of work, and can serve as a useful tool for researchers both in that country and working in other areas. In contrast to many low and middle income countries, India has an extensive research literature on ASD dating back more than 50 years, and provides rich data for a literature review.
This study presents a comprehensive review of published literature related to India dating between 1944 and 2010, and provides a detailed protocol for researchers interested in using a similar approach in other areas of the world.
We performed a comprehensive review of all journal articles by researchers in India, appearing in Indian journals, or using an Indian population. In order to include articles that appeared in journals that were not indexed or that pre-dated indexing, four key Indian journals were manually reviewed at libraries in India from the beginning of their publication. Dimensions were developed for coding for salient characteristics of the publications, including the type of publication, origin of publication; authorship; type of study; characteristics of participants; terminology used; and process and criteria used to confirm diagnosis of ASD, among others. Interrater reliability was used to establish consistent coding for all dimensions that involved subjective judgment.
A total of 167 articles were identified for inclusion in this review. Publications appeared in 82 journals, 33% of which were based outside of India. The majority of publications (70%) involved participants, with sample sizes ranging from 1 to 150 people with ASD (M=27.1, SD=3). An additional 19% of publications were theoretical or overviews, and the remainder were letters or responses. Study types were varied, and included experimental designs, psychometric, genetic, epidemiological, descriptive and health systems research, among others. Studies frequently included participants spanning a broad age range, but more than half (54%) focused on children between 2-11 years old. Adult populations were virtually unstudied. Diagnostic criteria to confirm ASD were not reported in one third of the studies involving subjects. For studies reporting criteria, approximately 61% relied on the DSM, 30% on the ICD, and 40% on an ASD-specific tool (a third of studies used more than one tool). 20 different studies reported using the CARS, either alone or with other criteria.
These and related findings provide insight into the growth of ASD in a non-Western setting through the lens of research. As interest in conducting research in low and middle income countries increases, conducting a review of the literature in these areas is an invaluable resource prior to entering the field. Synthetic reviews help investigators build on existing information rather than replicate well documented findings. Moreover, information from this rich source of information can be used to expand our global clinical picture of autism in the absence of large population studies.
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