Predictors of the age of autism spectrum disorder diagnosis: A North Carolina Cohort

Background and aims: This study investigated timing of diagnosis for African American = 50) and European American (n = 118) children with autism spectrum disorder in a North Carolina sample. Methods: Using survey methods, a total of 168 North Carolina families were recruited. Results: The two racially diverse groups did not differ significantly in the age at diagnosis of autism spectrum disorder (African American: M = 49.72, SD = 25.83; European American: M = 43.78, SD = 20.16; t(75) = 1.45, p=.15, 95% CI [-I4.10, 2.22], d=.27; BF10 = .582). Exploratory analyses revealed that within the African American sample, the age of diagnosis was positively correlated with parental ratings of Social Motivation from the Social Responsiveness Scale (r=.30, p <0.05). This correlation was non-significant and close to zero (r= -0.03, p>0.05) for the European American sample. Additionally, children who received another initial diagnostic label had a later age of diagnosis for autism spectrum disorder. This finding had a larger effect size in the African-American group. Conclusions: The differential findings for the two groups may reflect variable interpretations of autism spectrum disorder symptoms, or a greater impact of later diagnosis on symptom severity in certain populations.