Autism is a condition characterized by impairments in communication, social interaction, and stereotyped or repetitive behaviors. No one knows with certainty what has caused autism prevalence--which has increased roughly ten-fold in the past forty years--to increase so precipitously. Our group is devoted to learning why there has been such an increase.
Although we do not know all of the answers, we know a few things for certain. The first is that the reasons for increased prevalence are numerous and complex. No single causal agent is responsible. We also know that to make sense of the autism epidemic we have to make sense of the role of time and space. Our work focuses on analyzing birth cohorts. The problem we are interested in is why children born in different years are at different risk for autism. We also focus on where children are born, where they live, and where they were diagnosed with autism. This is because we know that environments in which children live play a critical role in their later experiences, one of which may be a diagnosis for autism.
To date, our work has focused on trying to understand how temporality influences the patterns of concordance for autism amongst twins and siblings; how changes in diagnostic criteria have influenced the measured prevalence of autism; how children with autism are distributed across different neighborhoods (and why); how information that diffuses from parent to parent about autism helps parents secure diagnoses for their children; how modeling developmental trajectories can influence our understanding of the heterogeneity of autism; how the institutional and political climate shapes diagnoses for those of Hispanic origin; and how to make sense of the role that parental age plays in the increased prevalence of autism. All of this work is reflected in articles that are (or will shortly be) available on this website.
We are also working on a range of new projects that we hope will shed more light on why autism prevalence has increased. So far our work has focused on California and on the analysis of large-scale administrative data. We are now anxious to develop a better understanding of the national picture, and also the experiences of parents and children. We believe that this will allow us to see things we have not yet seen, and maybe, to test hypotheses we have not yet considered. The Life Histories project is designed to help us with that goal.
Right now we believe we understand approximately half of the increase. That leaves another half unexplained. Whether one sees the glass as half full or half empty , there is still a lot of work to do.