Autism spectrum disorders and their treatment with psychotropic medications in a nationally representative outpatient sample: 1994-2009.

Purpose: No prior studies have assessed change in health care provider-coded rates of Autism spectrum disorder (ASD) diagnoses over time, and few have investigated sociodemographic factors associated with having an ASD diagnosis, having behavioral conditions comorbid with ASD, or using psychotropic medications for this group.

Methods: We used data from the 1994-2009 National (Hospital) Ambulatory Medical Care Surveys for children aged 2-18 years (n = 158,488).

Results: Rates of visits with coded-ASD per 100 outpatient medical visits increased from 0.04% to 0.82% from 1994 to 2009. Factors associated with an ASD diagnosis included male gender, lack of private insurance, white race, and later study period. The most frequent comorbid behavioral diagnoses were ADHD, anxiety, disruptive behavior, and mood disorders. Older age was linked to an increased likelihood of having a comorbid behavioral diagnosis and using psychotropic medications. Geographic region was also associated with having a comorbid behavioral diagnosis, and psychotropic use was linked to have a behavioral comorbidity. Comorbidities with the highest rates of psychotropic use were ADHD, mood, and anxiety disorders.

Conclusions: Pediatric outpatient visits with an ASD diagnosis have increased dramatically from 1994 to 2009. Further study is needed to determine the reasons for the observed sociodemographic disparities in ASD diagnosis.