What are the trends in autism research?
Funding of autism research
According to the National Institutes of Health (NIH) Research Portfolio Online Reporting Tools (RePORT), the total NIH funding allocated to autism research in 2007 was $93 million. NIH funding for autism research has increased every year since then and is expected to be $163 million in 2012 (Figure 1). In the past 5 years, there has been an overall increase of 75% in the total NIH funding allocated to autism research. This increase is significantly larger than the corresponding growth in the total NIH budget and in funding for other related research fields (Figure 2). These data reflect the recognition by NIH policy makers of the value of advancing autism research in the United States.
Figure 1. Histogram of the total NIH funding of autism research since 2007.
Figure 2. Percent change since 2007 in total NIH budget, NIH funding for autism research, and funding for nine other related research fields.
Autism in the scientific literature
Two important trends are seen in the scientific literature about autism research in the past 30 years:
(1) In the last two decades of the 20th century (1981–2000), there was a marginal growth in autism-related publications, with an average of 9 new papers per year with “autism” in the title and 16.5 new papers per year with “autism” in the title or abstract (Figure 3).
Figure 3. Histogram of the number of new publications per year on autism in PubMed between 1981 and 2010. Red bars indicate the number of publications with “autism” in the title, and blue bars indicate the number of publications with “autism” in the title or abstract
(2) In the first decade of the 21st century, there was an exponential increase in autism-related publications, with an average of 97 new papers per year with “autism” in the title and 163 new papers per year with “autism” in the title or abstract. This “explosion” in the scientific literature is unique to autism and is not seen in other related research fields (Figure 4).
Figure 4. The number of publications with “autism” (in units), “schizophrenia” (in tens), and “cancer” (in hundreds) in the title, as a ratio of the total number of publications in PubMed (in thousands) between 1981 and 2010, are shown in red, green, and blue, respectively.
Autism susceptibility genes
In 1992, the first gene associated with Autism Spectrum Disorder (ASD) was discovered (GLO1). In the next four years, four additional autism susceptibility genes were discovered (one every year until 1996). In the late 1990s and the early 21st century, new high-throughput genomic technologies have emerged, leading to an increase in discoveries of new genes associated with ASD (Figure 5). A total of 268 genes have been associated with ASD in the past 20 years.
Figure 5. The number of new ASD-associated genes discovered per year (red bars, left vertical axis) and the cumulative number of known ASD-associated genes (dotted line, right vertical axis).