Trends in autism spectrum disorder diagnoses: 1994-2007.

We analyzed predictors of parent-reported initial diagnosis (autistic disorder [AD], pervasive developmental disorder-not otherwise specified [PDD-NOS], pervasive developmental disorder ['PDD'] and autism spectrum disorder ['ASD'], and Asperger syndrome [AS]), among 6,176 individuals with autism spectrum disorders diagnosed from 1994 through 2007. Overall, distribution of diagnoses was influenced by a secular time trend factor; other significant factors included ethnicity, white race, geographic location, urbanicity, and initial evaluator. Since 2001, most initial diagnoses of AD and AS have remained steady while 'PDD' and PDD-NOS have decreased. 'ASD' diagnoses have increased, especially among school-based teams; AS diagnoses also increased uniquely among these evaluators. Findings from this study suggest that current diagnostic guidelines may not be meeting all community evaluator needs.