Introduction to Special Issue ASD in Adulthood: Comorbidity and Intervention.

The intent of this special issue was to shine a spotlight on research examining the assessment and treatment of cooccurring problems among adults with ASD. As the number of adults with ASD has risen, the need for researchbased guidance on how to best meet this population’s needs has become apparent. This growing need is evident in the rate of scholarly productivity in this area. A cursory GoogleScholar search reflects the upsurge in scientific interest in this area. A search of ‘adult autism’ yields 21,000 results from 2014 to October 1, 2015. This doubles what was seen just a decade earlier (2004–2005), for which a search with the same search terms yields only 10,900 results. In the summer of 2014, we issued a call for submissions for this special issue on ASD in Adulthood, with a focus on Comorbidity and Intervention. We had many excellent submissions, and all were subjected to JADD’s standard masked peer review process. The ten articles comprising this special issue fall into four broad domains, which can serve as a blueprint for future research on some of the key issues our field faces. The first domain broadly relates to diagnostic evaluation of ASD in adults and diagnostic stability. Louwerse and colleagues examined the stability of ASD dimensionally, using the calibrated severity scores of the ADOS. They found that stability over a 7-year period was fairly high, from childhood (mean age 9 years) into adolescence (mean age 16 years). Consistent with prior research in this area, they found that although ASD is diagnostically stable, dimensionally there are fluctuations in severity of ASD over the life course. Additionally, most of the individuals who no longer met diagnostic criteria for ASD at the 7-year follow-up had other psychiatric disorders. Louwerse and colleagues did not, however, find evidence for a linear relationship between ASD severity and psychiatric comorbidity. The mechanistic relationship between ASD severity and the emergence or presence of other disorders is complex, and further work is needed at both the diagnostic and dimensional levels to better understand how ASD, and secondary symptoms, change developmentally. Using a large, well-characterized multi-site sample, Pugliese and colleagues conducted a replication of the Autism Diagnostic Observation Schedule (ADOS-2, Lord et al. 2012) revised diagnostic algorithm (Hus and Lord 2014). They found that the 2014 revised algorithm yielded increased sensitivity but lower specificity. Interesting group patterns in their sample emerged. For example, specificity was lowest for adults of average cognitive ability, and both sensitivity and specificity were higher among females relative to males. The authors concluded that best practice with adults, similar to that for children (Dunn 2000; Le Couteur et al. 2008), is use of the ADOS in conjunction with other methods of evaluation, to support accurate differential diagnosis. In the second domain, we have five articles pertaining to psychiatric comorbidity, including its expression, assessment, and relationship to core ASD symptom severity. Kreiser and White, in an analogue sample of healthy adults, found that ASD traits positively predicted likelihood of & Susan W. White sww@vt.edu