Psychometric Evaluation of Two Adult Autism Screening Tools in Brazil

Despite increasing rates of autism spectrum disorder (ASD) in many countries, substantial evidence suggests persistent underdiagnosis of ASD in many low and middle-income countries, such as Brazil. Underdiagnosis or misdiagnosis may be particularly prevalent among women who often present subtler social and behavioral characteristics, engage in camouflaging strategies, and exhibit different symptom expressions compared to men. This study evaluates two new instruments to improve screening for ASD among adults in Brazil: the Screening for Autism in Adults (SfA-A) and the Screening for Autism in Females (SfA-F). A sample of 3302 Brazilian adults (mean age = 37.55 ± 11.34 years) completed the SfA-A, while 7738 Brazilian adult women (mean age = 38.77 ± 10.28 years) completed the SfA-F. Exploratory Structural Equation Modeling was conducted. Reliability was assessed using Cronbach's alpha, McDonald's omega, and test-retest. Criterion validity was determined by the AQ-10 and two autism-related questions. Norms were established based on percentiles. Exploratory and confirmatory factor analyses indicated that the SfA-A and SfA-F exhibited strong model fit, high internal consistency (α > 0.8), and initial evidence of criterion-related validity. The SfA-A and SfA-F were developed to address critical gaps in ASD screening among adults in Brazil. These tools hold promise for identifying ASD symptoms and can be used to initiate formal ASD evaluation.