An overview of developments in research on persons with intellectual disabilities

Intellectual disabilities (ID) are one of the largest, most complex, and frequently studied of the mental health and medical specialty areas. Thousands of papers have been published dating back to the early work on IQ testing more than a century ago. Many reviews have been published on specific topics with the field of ID, but to date no papers have appeared providing an overview of trends in this vast literature. In this paper we looked at studies published in referred journals from 1979 to 2008. Fifty-six thousand, three hundred and twenty studies were identified using the terms mental retardation and ID. The number of papers published per year ranged from 1038 to 2075 with the fewest papers published in 1980 and the greatest number of studies appearing in 2005. Genetics was by far the most frequently studied topic. The implication of these and related trends in the literature are discussed.